Device with through-hole interconnection and method for manufacturing the same

Mode of execution

With the below detailed description with reference to the example embodiment of the present invention. The described exemplary embodiment the purpose lies in the understanding of this invention, and is not intended to be limiting in any way the scope of the invention.

More specifically, Figure 1-3 described wherein use is made of an insulating base plate of the exemplary embodiment, and Figure 4 to 6 illustrates that the example of using the embodiment of the conductive base plate. Each graph diagrammatically shown according to the example embodiment of this invention the structure of the device, and some with floorplan in order to provide a more clear understanding.

Figure 1 is cross-sectional view of illustrative, of the present invention is described according to an example embodiment of the device, and a small hole (hole) is provided and the whole inner wall of the hole by the 2nd conductive region made of conductive material is totally covered. As used here, the term "the whole inner wall of the hole" includes the bottom of the hole (the back side of the namely pad) and the inner side wall of the hole.

As shown in Figure 1 the device 10 comprises an insulating material, such as glass, which is made of ceramic such as 1st base plate 11, functional element 12, such as the light-emitting device, is provided in the 1st base plate 11 of the 1st side (the upper side in the Figure) on the pad 13, electrically connected to the functional element 12 and pad 13 between 1st circuit (wiring) of 14, is electrically connected to the pad 13 interconnecting the through hole 15, and the conduction region 18. The through-hole interconnection 15 is from the 1st to the 2nd side of the side (the lower side in the Figure) inner surface of the bore 16 the at least one part of the [...] 1st conductive material filled in 17 and form. The conduction region 18 is different from the conductive material 1st 17 made of conductive material the 2nd. Here, of the interior surface of the aperture comprises limiting the pad 13 of the rear side (in the hole before the formation of the 1st base plate 11 contact side) of the bottom of the hole and the inner side wall of the hole. A reference digital 18a indication provided in the hole of the conductive area of the bottom of the part. A reference digital 18b indication provided in the hole of the inboard wall of the remaining portion of the conductive area.

As the pad 13 and 1st circuit 14 material, exhibits good conductive material is preferably used, for example aluminum (Al), copper (cu), aluminum-silicon (Al-Si) alloy, or aluminum silicon copper (Al-Si-Cu) alloy. However, these material is easy to be oxidized.

As a through-hole interconnection 15 of the 1st conductive material 17, in addition to metal if tin (Sn), gold-tin (Au-Sn)-based alloy and the like, a solder such as tin (Sn) based, lead (Pb) based, gold (Au) yl, indium (In) base, such as solder, and aluminum and the base (Al) is preferably used.

As the conduction region 18 of the 2nd conductive material, that exhibits conductivity and on the through-hole interconnection 15 1st of the excellent wettability of an electrically conductive material, oxidation resistant, and can prevent conductive material included in the 1st 17 in the diffusion of the elements of the material can be preferably used. Such a material include, for example, when using the single-layer of gold (Au), titanium (Ti), titanium-tungsten (TiW), and when using the stacked layer of gold (upper layer)/ copper (lower layer).

The conduction region 18 are disposed in the inner surface of the hole 16 the of [...] at least a portion of the inner surface, in order to make its performance its effectiveness.

Figure 2 is cross-sectional view of illustrative, note according to the present invention is provided with a base plate 21 of the device 20 of the embodiment of another example. In this Figure, the part of the said conductive portions 28 (hereinafter, referred to as " conductive the 28 [...]) is only provided in the pad 23 of the rear side of the bottom of the bore, its corresponding to the Figure 1 shown in the embodiment of the 18a. Via-in-pad 23 to provide the rear side of such a conductive region, the conductive area 28 for a long time to maintain the pad 23 is interconnected with the through-hole 25 the excellent conductivity between, because pad 23 oxidation can be prevented.

In fig. 2 in the structure shown, can improve the 1st conductive material 27 and the pad 23 the adhesion between is preferably used as the material of the conduction zone 28. Vitric tray bottom 23 and Cr cu having a double-layer structure made of a specific example is the gold-tin (Au-Sn)-based alloy as a 1st conductive material as conductive nickel (Ni) 27 and 28. Preferably, the Ni is formed by plating or sputtering method.

Figure 3 is cross-sectional view of illustrative, shows that the apparatus according to the present invention 30 of another example embodiment. In this Figure, part of the conductive regions 38 (hereinafter, referred to as " conductive the 38 [...]) is provided only on the side wall of the aperture, its corresponding to the Figure 1 shown in the embodiment of of 18b. Through to 1st base plate 31 to provide the conductive region in the hole, the through hole interconnection 35 and 1st base plate 31 between the lead to the weakening of the adhesion of the interconnect the through hole 35 a shift in the aperture, and the through-hole interconnection so that the 35 can be of the from the hole is prevented. As a result, through-hole interconnection 35 can be held for a long time to the pad 33 the excellent conductivity.

In Figure 3 in the structure shown, the conduction region 38 preferably has the conductive material contained in the 1st 37 to the 1st diffusion of elements in the base plate 31 in characteristic. As the material combination of the specific example, when the 1st conductive material 37 composed of gold-tin (Au-Sn)-base alloy and 1st base plate 31 is made of silicon, nickel (Ni) or titanium nitride (TiN) is used for the conduction region 38. Preferably, Ni is the use of the sputtering method or plating, and is TiN by a sputtering or chemical vapor deposition (CVD) method for forming.

The conduction region 18 can be disposed in the inner surface of the bore 16 the on the whole surface of [...] , as shown in Figure 1. Because in addition to the pad 13 and the through hole interconnection 17 between the outside of the long-term reliability of the conductivity of, the through-hole interconnection 17 the long-term reliability of the conductivity can be ensured also, the provision of the conduction region 18a and the conduction region 18b is preferred.

Furthermore, in fig. 1 in the structure shown, can improve the hole 16 the [...] and the inner surface of the pad 13 adhesion between the material is preferably used for the conductive region 18. As the material for improved adhesion of the specific examples of the combination, when the 1st conductive material 17 composed of gold-tin (Au-Sn) the based alloy, gold (Au) is used for the conduction region 18. In this situation, is preferably Au using plating or sputtering method is formed.

In Figure 1 in the structure shown, the conduction region 18 preferably has the conductive material contained in the 1st 17 to the 1st diffusion of elements in the substrate 11 of the in. As used for prevent material diffusion of the material combination example, when the 1st conductive material 17 composed of gold-tin (Au-Sn)-base alloy, nickel (Ni) is used for the conduction region 18. In this situation, is preferably Ni plating or sputtering method to form the.

In Figure 1 in, the pad 13 is shown in the layout of expounds the pad 13 interconnected with the through-hole 15 of the positional relation between the. The through-hole interconnection 15 and the pad 13 contact between the (that is, the hole 16 the [...] is defined by the perimeter of the through hole) is preferably the pad 13 and 1st base plate 11 having a rectangular periphery of the between the contact area. In this configuration, when the hole from the 1st base plate 11 of the 2nd side (the underside in the Figure) formed, can ensure that the through-hole interconnection 15 and the pad 13 in the whole contact area between the pad 13 and 1st base plate 11 in the contact zone between the. Therefore, pad 13 and 1st base plate 11 of the contact is established between.

In this structure, because the base plate 11 and the pad 13 no gap between, when the 1st conductive material 17 is filled into the holes in order to form the through-hole interconnection 15 is, 1st conductive material 17 is prevented from flowing to the 1st base plate 11 of the 1st side (the upper side in the Figure). Therefore, the already provided in the 1st base plate 11 to the circuit 14 and device 12 can be prevented from the adverse effects of. Therefore, it is possible to form a highly reliable electrical connection.

Figure 4-6 is a local illustrative cross-sectional diagram, according to the present invention described the other embodiments of the device, wherein the conductive material is the arsenide or galliumif silicon for 1st base plate.

Figure 4 is a local illustrative cross-sectional view, illustrates the device of this invention according to another example embodiment. In this Figure, the dielectric region made of insulating material 49 is provided in the internal side wall of the hole the 46 on [...] , and the inner wall as a whole (that is, dielectric region 49 and pad 43 the rear side) is made by the conductive area of 2nd conductive material 48 covering. As used for dielectric region 49 of the insulating material, for example silicon oxide (SiO₂), (SiN) silicon nitride, or silicon oxynitride (SiNO_x) can be used.

That is to say, when the 1st substrate 41 is composed of a conductive material, it is possible to through the base plate 1st 41 in sidewall of the hole of the 46 [...] are provided on a dielectric region made of insulating material 49 to define the above-mentioned structure. By the 2nd conductive region made of conductive material 48 to cover the dielectric region pad 49 and 43 in the rear side of fig. 4 is shown in the device for a long time to maintain pad 43 interconnected with the through-hole 45 of the conductive material in 46 the fine electrical connection between, as shown in Figure 4 is shown in. Pad 43 (wiring) through the 1st circuit 44 is electrically connected to the functional element 42.

Figure 5 is cross-sectional view of part of the illustrative, shows that the device according to the invention is another example of the embodiment. Similar to Figure 4 of an example embodiment, the device comprises a 1st base plate 51, functional element 52, circuit 1st-hole interconnection 54 and 55. In this Figure, only the side wall of the hole in the 56 by [...] dielectric region made of insulating material 59 is provided later, the conduction region made of conductive material 3rd 58a is provided in the dielectric region only 59 is. Subsequently, the conductive pad 58a and 53 the back side of the 2nd is made by the conductive material of conductive section 58b covering.

As shown in Figure 5 is shown in, the conduction region 58 has two-layer structure, and each layer has a different function. For example, the dielectric region to 59 contact the outer conductive region 58a 3rd conductive material of, the performance of the dielectric region 59 of the excellent adhesion material can be used. On the contrary, for the 1st is made of electrically conductive material of the through-hole interconnection 57 2nd contact of the conductive material, conductive material on the 1st 57 with fine wettable material is preferably used. For example, when the dielectric region 59 is formed by silicon dioxide (SiO₂) and conduction region 1st 57 (that is, through-hole interconnection) is composed of a gold-tin (Au-Sn) the alloy, chromium can be used for the conduction region 58a 3rd of conductive material, can be used and applied to the conduction region 58b of the 2nd conductive material.

In Figure 5 is shown in the example, the conduction region 58a only covers the dielectric region 59. Optionally, in the provision of the conductive area 58a in order to cover the dielectric region pad 59 and 53 after both the rear side of the, can provide the conduction region 58b in order to cover the whole conduction region 58a.

Figure 6 is cross-sectional view of part of the illustrative, shows that the device according to the invention is another example of the embodiment. Figure 6 of the device and the Figure 5 device is characterized in that the different electrical medium area and two said conductive portions of the opening from the bore to the 1st 2nd side of the base plate.

A dielectric portion 69, is composed of two layers of conduction region 68a and 68b form a conductive region 68 is similar to the Figure 5 device and provide in the hole in sidewall of the 66 in [...] , and this embodiment is characterized in that the opening of the from the bore 1st 2nd side of the base plate to the end of the extension of the 69 [...] , the 68a [...] and 68b the relative length of the [...]. More specifically, the dielectric portion 69 at the tail end of the 69 [...] can be the longest, and the conduction region 68a end 68a the conduction region [...] and 68b at the end of the the 68b can be [...] than the ends 69 the short [...]. According to this structure, because it can ensure that the dielectric portion 69 at the tail end of the 69 [...] is provided in the the 1st base plate made of conductive material 61 and the conductive area 68a the end of the the 68a [...] or conduction region 68b at the end of the the 68b between [...] , it is possible to prevent a 1st base plate 61 and the conductive area 68a or conduction region 68b short circuit between the.

In a hole of the above-mentioned structure, the 1st through the hole is filled with a conductive material 67 forming a through-hole interconnection 65, the through-hole interconnection 65 from the opening of the hole to the tail end of the to the outside (Figure 6 in the lower side of the of) extended, so as to define a semi-spherical end. The through-hole interconnection 65 of the hemispherical end of the 65 [...] is formed in order to make said semi-spherical end of the 65 [...] completely covers the conduction region 68b at the end of the the 68b [...].

The through-hole interconnection 65 of the semi-spherical end of the 65 [...] is preferred, because it can be used as a terminal, disposed on the substrate through the 1st function element on the side 62 may define the electrical contact with an external element. The function element through the 1st circuit 64 (wiring) is electrically connected to the pad 63.

Figure 7 is cross-sectional view of illustrative, shows that the apparatus according to the present invention 70 another example embodiment. It is assumed that the conductive material such as silicon or gallium arsenide is used as the 1st base plate 71, and insulating material such as glass or ceramic is used as the 2nd base plate 81, Figure 7 the characteristic of the device has the following:

(A) 2nd base plate 81 is coupled to the 1st base plate 71 of the 1st side (the upper side in the Figure) at least a portion of the.

(B) 2nd base plate 81 is positioned so that the 2nd base plate 81 covers the pad 73 at least a portion of the.

(C) from the hole 76 of the dielectric region extending 79 covering 1st base plate 71 of the 2nd side (the lower side in the Figure) the entire surface of, and is electrically connected to the conductive area and the through-hole interconnection of 78 the 2nd circuit 82 is provided. The through-hole interconnection 75 including 1st conductive material 77. Furthermore, the projection 83 can be offered in the 2nd circuit 82 is.

The 1st base plate 71 is provided in the (a) described in 2nd base plate 81, the device can be formed after the through-hole interconnection is used as a package, wherein said 1st provided with a functional element on the base plate 72, 1st circuit 74, pad 73 and the through-hole interconnection.

Specifically, such as (b) described in, the 2nd base plate 81 is positioned so that 2nd base plate 81 covers the pad 73 at least a portion of, the hole it is possible to prevent the 76 after the formation of the bat because the stress caused by the deformation or degradation of the strength of the pad.

Furthermore, very thin because of pad (for example approximately 1 the  m), from the related technology the 1st to 2nd side of the base plate in the process of forming a hole of the pad may be damaged or destroyed. In order to prevent damage or destruction of the pad, as shown in Figure 7 is shown in, 2nd base plate 81 is provided in order to make its contact 1st substrate 71 side of the 1st grips the pad of 73. In this configuration, if the pad 73 the rear side (the side of the substrate contact 1st) during the formation of the hole is subjected to a certain force, the contact pads 73 of the front side (the side of the substrate contact 2nd) 2nd base plate of the 81 support the pad 73. As a result, by the 2nd base plate 81 support the pad 73 is relatively less susceptible to the influence of the process of the formation of the hole, and the pad 73 damage or destruction can be prevented.

Furthermore, by providing such as (c) the 2nd in circuit 82 and the projection 83, it is possible to realize the chip level packaging. Therefore, can realize reduction of the size of the device. In particular, by changing the 2nd circuit 82 position, and the through-hole interconnection 83 interval between the can be changed to any value. For example, even if the interconnection hole when passes the spacing between the narrow (pitch), can still by appropriately setting circuit 2nd 82 and [...] 83 the distance between. Therefore, the device and the external element can be easily combined. Furthermore, because the 2nd circuit 82 allow the projection 83 is provided in the different from the through-hole interconnection 2 in the region of the area of the above, in the form a lug 83 of the process or to the projection 83 of the through hole in the course of the combination of the interconnection can be less affected by heat or mechanical forces. Therefore, the through-hole interconnection 83 the reliability of the electrical connection between the can be strengthened.

Figure 8 is cross-sectional view of illustrative, shows that the device according to the invention is another example of the embodiment. Figure 8 the device has the following features, and in addition, Figure 8 is similar to the described above the device of the fig. 7 structure of the device:

(D) has at least two layers of multi-layer circuit is provided in the 1st base plate 91 of the 2nd side (the lower side in the Figure) is, and the circuit of the interlayer is inserted into the insulating layer is made of a resin, for example, 111. In Figure 8 is shown in the example, circuit has a two-layer structure, with the same circuit 2nd 112 and 3rd circuit 114.

(E) 2nd circuit 112 and 3rd circuit 114 through the through-hole interconnection made of conductive material 113 is connected electrically.

(F) projection 115 is provided in the insulating layer 111 of the surface of 3rd circuit 114 is.

Similar to the Figure 7 device, which is provided with the through the functional element 92, circuit 94, the pad 93 and 1st of the through-hole interconnection substrate 91 to provide 2nd base plate 101, Figure 8 device 90 can be formed in the through-hole interconnection is used as a package. Also similar to that of Figure 7, Figure 8 device includes a hole 96, 1st conductive material 97, the conductive electric medium zone 98 and 99.

Furthermore, through such as (f) the in providing the projections 115 to electrically connect to the 2nd circuit 112, it is possible to realize the chip level packaging. Therefore, can realize the reduction of the size of the device. In particular, the fig. 8 device has multi-layer structure, in the 1st base plate 91 on the side of the 2nd has at least two layers, thus are useful as with the external element of the electric contact of the lug 115 flexibility for selecting the position of the can be further enhanced. For example, as shown in Figure 8 is shown in, it is possible more than the through-hole interconnection of providing the projections 115.

A method for manufacturing the apparatus according to the present invention method includes: step A, including 1st 1st and 2nd side of the side of the base plate, wherein the functional element is provided in the 1st 1st on the side of the base plate, the circuit is connected to the 1st function element, and is electrically connected through the 1st circuit pad of the functional element; and step B, from 2nd to 1st kong Zhi side of the base plate to the pad is exposed; step C, in the the inner surface of the hole is provided on at least a portion of the conduction region made of conductive material 2nd, 1st 2nd conductive material is different from the conductive material; step D, the 1st conductive material filled in the hole.

In this configuration, it is possible to effectively manufacture the inner surface of the hole having at least a portion of the device of the above-mentioned structure (i.e. including the different from the through-hole interconnection of the 1st conductive material the 2nd is made of an electrically conductive material of the conductive area of device is provided, as shown in Figure 1). Furthermore, since the front side of the pad in the hole is formed and immediately after the pad is exposed by the conductive cover (metal film), even if the pad is formed by easy oxidized metal, for example aluminum, the surface side of the mat can be stable 2nd is made of an electrically conductive material of the conductive area of protection. Therefore, the cushion can be through establishing said conductive portions 1st with the filling of the conductive material is electrically connected to the highly reliable.

The steps of the described above in B, deep reaction ion etching method (hereinafter referred to as "method for DRIE") can be used to form the hole. The DRIE method can make the hole is formed with high precision, the hole can be formed in the periphery of the pad.

In the below, will use the silicon wafer substrate is the 1st examples of steps of forming the hole in B program. A typical silicon wafer includes a substrate (Si) and the oxide layer formed thereon (SiO₂). The pad is made by aluminum (Al) set up in limit 1st 1st side of the base plate of the oxide layer (SiO₂) on, and in the following two steps (i) and in (ii), hole from 1st 2nd side of the base plate:

(I) of the substrate to be formed of hole (Si) side of the 2nd 1st part is exposed to the plasma, which is able to etch the substrate using a SF6 (Si) of the generated gas, and 1st.

Having a certain opening size of the hole is formed on the substrate in the side of the 2nd (Si), and the depth thereof is gradually increased. Because plasma etching oxide layer 1st (SiO₂) to silicon the etching rate compared with the etching rate is very small, when the oxide layer (SiO₂) is exposed to the etching reaction stop. Therefore, use of a 1st gas is completed. In other words, oxide layer (SiO₂) also plays the role of the etching stopper.

(Ii) subsequently, comprising CF4 use of the gas, and a 2nd 2nd plasma is irradiated onto the aperture. CF4 is able to etch oxide layer (SiO₂). Because plasma 2nd not etching the silicon (Si), is exposed to the bottom of the hole the oxide layer (SiO₂) is etched. The depth of the hole as the SiO₂ increase of removing. Because plasma 2nd not etching the pad (Al), vitric tray bottom is exposed (Al) stops the etching reaction. Therefore, use of a 2nd gas is completed. In other words, the pad (Al) also plays the role of the etching stopper.

In the above-mentioned two etching steps, the opening of the base plate of the 1st 2nd side and has the hole at the bottom of the defined the pad rear end is formed.

C in the above-mentioned step, the conduction region is formed in order to make it extend to the opening of the from hole 1st 2nd side of the base plate. Through the conduction region is so formed that it extends from the inboard wall of the hole into the hole in the vicinity of the opening of, 1st base plate formed on the rear side of the circuit is able to establish more reliable electrical connection and the adhesion can be further improved.

C in the above-mentioned step, the conducting region is made from a different material by stacking of two or more layers of the formed. The multilayer structure can be is composed of a 1st the 1st of the base plate is made of a material excellent in the adhesion, and using, for example, 2nd layer is continuously formed by the film deposition process. As a result, the efficiency of the production process can be improved.

In D the above-mentioned step, molten metal suction method is used for filling the 1st conductive material. Through the conduction region is formed on the inner wall of the hole, compared with the relevant technical field, it is possible to remarkably enhance the molten metal suction method for the filling of the molten metal (for a through-hole interconnection of conductive material 1st) between with the 1st the adhesion of the base plate.

C in the above-mentioned steps has already been formed by the 2nd of said conductive portions made of conductive material can be patterned by using a dry film resist. In the process of patterning wet slushing compound , liquid resist is typical to use, and because the resist may be flows to the aperture, in the rear thereof in the step of removing the is difficult. Within the bore of the remaining resist can adversely affect electrical characteristics of the through-hole interconnection. On the contrary, when the dry film resist is used, the opening of the resist covering the hole. Therefore, due to the use of dry film resist is not patterned of the remaining issues of the above-mentioned hole, and can be formed and demonstrated excellent electric characteristics of the through-hole interconnection.

The following, the reference picture 9A to 9F a detailed description of manufacturing according to an example embodiment of the present invention method of the device. Figure 9A to 9F is illustrative cross-sectional diagram, note for the production according to an example embodiment of the present invention in the device of the steps of the method of, and some with the floorplan in order to provide a clear understanding.

In Figure 9A in, a solid-state Image sensing device is shown. The device is used to make the manufacturing process of the related technology, and includes: a substrate made of silicon 171, includes a series of photoelectric diode and functional element of a set of micro-lenses 172, for providing with the external element of the connection of the pad 173, and electrically connected to the pad 173 and functional element 172 circuit between 174. In this example, silicon substrate 171 has 200 the thickness of   m, and pad 173 and circuit 174 is made of aluminum (Al). Pad 174 is the 100  m× 100 the square   m.

First of all as shown in Figure 9B shown in the, to penetrate the base plate 171 with the inner surface of the 176 [...] the hole 176 in the pad 173 (the upper side in the Figure) from the relative position of the functional element 172 is formed the side opposite side (the lower side in the Figure) is formed, until the rear side of the pad is exposed. In this step, the pad 173 of the underlying aperture 176 is the entire circumference of the inner wall of the pad 173 in the periphery of the. Through such, when the in the step of the conductive material is filled into the hole 176 in order to form the through-hole interconnection 175 is, the through-hole interconnection 175 and pad 173 is defined the contact zone between.

In this example, has the 80   m of the diameter of the hole 176 is through the use of dry etching and removing the base plate 171 of the silicon, then remove the SiO₂ made of the insulating layer and the like (not shown) and defined, the insulation layer typically is provided on the pad. In this example, deep reaction ion etching (DRIE) method is used for etching silicon. The DRIE method, through are alternately carried out in order to use the sulfur hexafluoride (SF₆) as the etching gas of a high density plasma etching and to the sidewall of the forming of the passivation film (Bosch process), with a high aspect ratio etch the silicon substrate. The use of carbon tetrafluoride (CF₄) the RIE (reactive ion etching) is used for etching SiO₂.

Furthermore, as shown in Figure 9C shown in the, insulating layer 179 is formed in the hole 176 is made of it by silicon and on the inner wall of the base plate 171 of the 2nd side (the lower side in the Figure) the upper. In other words, insulating layer 179 includes covering the hole 176 of the inner wall of part 179a and covers the base plate 171 of the side of the 2nd part 179b. Forming the insulating layer 179 after the the bore by the reference symbol 176a to indicate. In this case, comprises a silicon oxide (SiO₂) insulating layer made of 179, is to use tetra ethoxy silane (TEOS) as a source of a plasma CVD method.

Furthermore, as shown in Figure 9D shown, located in a bore 176a of the bottom of the by SiO₂ insulating layer made of 179 through a part of the etching method to remove for. Located in a bore 176a of the bottom of the by SiO₂ insulating layer made of 179 is contact pads of the portion 173 of the rear side of the region. In order to remove the located in a bore 176a of the bottom of the by SiO₂ insulating layer made of 179 of the part, as a resist in use to the base plate 71 on the side of the 2nd SiO₂ after the protection layer, performing an anisotropic etching process. In this example, the use of four carbon fluoride (CF4) the RIE (reactive ion etching) to etch the SiO₂. At the bottom of the hole in the etch SiO₂ after layer, pad 173 is exposed to the rear side of the hole by the reference symbol 176b expressed.

Next, as shown in Figure 9E shown, a conductive film 178 is formed on hole 176b at around the inner wall and the opening. In this example, the conductive film 178 has a two-layer structure, through the use of sputtering method, deposition of chromium (Cr) as layer 1st, and 2nd layer deposition gold formed as (Au). In this course, hole 176b the inner wall, defining the inner side wall of the hole by SiO₂ insulating layer made of 179, defining the bottom of the hole and the pad 173 is provided with a rear side of the two-layer structure conductive film 178 is covered. The obtained hole by the reference symbol 176c expressed.

Furthermore, as shown in Figure 9F shown, conductive material 177 is filled with inlet hole 176c in order to form electrically connected to the pad 173 the through-hole interconnection of 175. In this example, comprising 80% by weight of gold and 20% of the weight of the gold-tin of the tin (Au-Sn) alloy is used as the conductive material 177, and molten metal suction method for forming a through-hole interconnection 175.

It should be noted that, although in this example the pad 173 is a 100 the the  m× 100 square   m, actual pad 173 can be in addition to the square of the other shapes, including circular, oval, triangular, or rectangular. As long as the pad 173 is used as the circuit, then the pad 173 can have any size. Furthermore, although the pad 173 and circuit 174 is made of aluminum in this example, the invention is not limited to aluminum, can be used for any circuit material, including copper (cu), aluminum-silicon (Al-Si), or aluminum-silicon-copper (Al-Si-Cu).

Furthermore, in this example the hole 176 is a the periphery of the 80   m the diameter of the round. However, hole 176 is not limited to the size of the diameter, and as long as the pad 173 to the contact-in-pad 173 in the periphery of the, hole 176 may have any size. Furthermore, hole 176 can be round the periphery of the shape of the outside, including oval, square, triangular, or rectangular. And then, the holes 176 for DRIE method is not limited to, an aqueous solution of potassium hydroxide (KOH) and wet etching method can also be used.

In this example, by SiO₂ insulating layer made of 179 by a TEOS plasma CVD method to form the spring in the hole 176 and the inner wall of the base plate 171 of the two 2nd side. However, the invention is not limited to this example, and silane (SiH₄) makes the source can also be used. And then, the insulating layer 179 can be formed by using the insulating resin coating, instead of using a plasma CVD method to deposit SiO₂.

Furthermore, although in this example the conductive film 178 to chromium and is provided with a two-layer structure of the system, the invention is not limited to this kind of layer structure, but can use of different materials, as long as the material has improved and the filled conductive material and the characteristics of adhesion of the inner wall of the hole. The number of layers is not limited to two, and the multi-layer structure comprises three layers or more of the multi-layer is possible. Forming a conductive film 178 method is not limited to the sputtering, and other method, such as CVD or evaporation can also be used.

In the examples described above, containing 80% by weight of gold and 20% of the weight of the gold-tin of the tin (Au-Sn) alloy is used as the conductive material 177, but this invention is not limited to this example. For example, different components of a gold-tin alloy; tin-lead (Sn-Pb) alloy; metal, such as tin (Sn), or indium (In); or such as tin (Sn) based, lead (Pb) based, gold (Au) yl, indium (In) based, or aluminum (Al) base solder can be used.

Examples

The below described one specific example. However, although with reference to the following example to a detailed explanation of the invention, the invention should not be understood as limited to the following examples. It should be clearly understood, this example only has the purpose of description, not to limit the present invention in as one of the defining.

Example 1

In this example, as shown in Figure 2, the only used for limiting pad 23 on the bottom of the rear side of the hole provides a Au (thickness: 300 nm)/ Cr (thickness: 50 nm) laminate made of, as the conduction region 28. Au layer is the contact through-hole interconnection 27 of the upper, and the Cr layer is a contact pad 23 of the rear side of the lower layer. Furthermore, this sample is designated as sample A, and the sample did not provide the through-hole interconnection 27. In the sample is placed in the air A 240 hours later, auger electron spectrometer for from the gold layer surface detection limit the conduction region 28 of the oxygen content of the stack layers. Figure 10 is graph of note the results of the auger electron spectrometer. In Figure 10, , curve A A representative of the results of the sample. In the sample A, measuring from the conduction region 28 on one side of the implement, and the abscissa axis represents depth. The origin of the horizontal axis (value 0) to the many corresponding to the begin to measure the depth of aluminum. The amount of oxygen which represent the detected longitudinal axis, and the value 1 to the detection of many aluminum of the amount of depth.

Comparative example 1

In this comparative embodiment, in addition to the conductive area 28 be omitted the outer, prepared with the Figure 2 shows the same embodiment of a sample structure B, B for example and the example 1 assessment of the described in. In other words, there is no conductive sample B 28, and maintain open the inner surface of the hole, without forming a through-hole interconnection 27. Figure 10 in, curve B B representative of the results of the sample. In the sample B, HAWT representative depth, the depth from the aluminum etching time to calculated, and the origin of the horizontal axis (value 0) corresponding to the surface of the pad rear end (aluminum). The amount of oxygen which represent the detected longitudinal axis, and the value 1 corresponds to the observation to the oxygen content of the aluminum layer surface. Figure 10 shows that, at the surface of the oxygen content is one-half of the depth to the sample is the depth A to the sample "a" and "b" is the depth B. Furthermore, the depth "b" than depth "a" deep by more than three times, means that the sample is oxidized B A the depth of the three times greater than the sample.

In other words, the surface of the (aluminum) pad rear end keep open B in the sample, form an oxide layer on the back side of the thermos bottle, this is not ideal, because the oxide layer to be reduced in the future of the conductivity of the formed through-hole interconnection.

By contrast, the conduction region made of Au/Cr 28 is provided in the pad 23 the back side of the sample of the degree of oxidation of aluminum in A B one-third of the sample, this is preferred, because good electrical contact is established within the pad 23 and subsequent interconnect to be formed between the through hole. In other words, the conductive area 28 of gold in play the role of preventing oxidation of the aluminum.

Example 2

In this example, as shown in Figure 3, only the 1st is limited in the base plate 31 in the side wall of the hole provides a on Au (thickness: 300 nm)/ Cr (thickness: 50 nm) made of the conductive member as 38. Au layer is the contact through-hole interconnection 37 of the upper, and the Cr layer is the lower layer of the inner wall of the contact hole. Then will be provided with a through-hole interconnection 37 C designated as the sample of the sample. Furthermore, the example C (sample number: 100) implementation of the following three test item reliability test. In the reliability test front and rear, for measuring through hole interconnection 37 and pad 33 (resistance) resistance between, and will show the 50% or less of the rate of increase through the sample of the sample is determined. C reliability of sample test results in table 1 are listed in the.

In the reliability test, the sample is maintained at an elevated temperature (test 1st), or is kept in the high temperature and high-moisture (2nd test), or is kept in the heat circulation (3rd test). These three kinds of test to the above-mentioned sequential execution.

In the high-temperature test in (1st test), sample in the 90 [...] temperature is maintained in the air for a total of 240 hours. In the high temperature and the high humidity in the test (test 2nd), sample in the 70 temperature and [...] 90% HR humidity is maintained in the air for a total of 240 hours. In the thermal cycle in the test (test 3rd), sample alternately on two kinds of different temperature (-40 the and [...] the 125 [...]) is maintained in the air under a total of 240 hours.

A heat cycle is composed of four steps: step 1 to step 4, and each circulation continuous 2 hours. In step 1 in, the -40 [...] temperature is maintained 30 minutes. In step 2 in, in 30 minutes in the temperature from -40 the rise to [...] the 125 [...]. In the step 3 in, the 125 [...] temperature is maintained 30 minutes. In the step 4 in, in 30 minutes from the temperature is in the 125 is reduced to -40 the [...][...].

Example 3

In this example, as shown in Figure 1, on the entire surface of the hole provides a Au (thickness: 300 nm)/ Cr (thickness: 50 nm) as a laminate made of the conductive area 28. Au layer is the contact through-hole interconnection 17 of the upper, and the Cr layer is a contact pad 33 and the rear side of the base plate 11 of the side wall of the hole in the lower layer. Furthermore, provided with a through-hole interconnection 17 is designated as the sample of the sample D. Furthermore, D the sample (sample number: 100) implementation of example 2 described in the reliability test. In the reliability test front and rear, through hole interconnection 17 and the pad 13 is measured resistance between, and will show the 50% or less of the rate of increase of the sample through the sample is determined. Sample D reliability test results are listed in table 1.

Comparative example 2

In this comparative embodiment, in addition to conduction region 38 outside are omitted, with the Figure 3 embodiment shown in the sample E the same structure (sample number: 100) is prepared, and the implementation example E example 2 assessment of the description of the in. In other words, there is no conductive sample E 38, and in providing the through hole interlocks 37, , the inner surface of the hole is exposed. Sample E reliability test results are listed in table 1.

Table 1

From table 1, the following observation results obtained:

(1) made of the laminate by Au/Cr is to provide 1st of the inner wall of the base defining a bore 31 of a conductive region on the inner wall 38 in sample C, 92 through which a sample is identified as a sample, its corresponding to the 90% through sample rate.

(2) made of the laminate by Au/Cr are provided as holes a conductive region on the entire inner surface 18 in sample D, 99 for a sample is determined through the sample, corresponding to the same close to 100% through the sample rate. Therefore, the number of defective samples will be small.

(3) in contrast, in the absence of conduction region 38 E in the sample, only 56 determined as the sample, its corresponding to less than 60% through sample rate.

These evaluation results show that only provides for the conduction region 38 the side wall of the hole, the through hole can be sufficient to maintain good of the conductivity of the interconnect. Furthermore, provide conduction region 18 the whole inner area of the hole, through the can be improved to sample rate close to 100%. Therefore, the conduction region 18 provided to the hole of the embodiment of the whole inner area (as shown in Figure 1) is the most preferred.

According to the present invention, provides a highly reliable electrical connection. Therefore, this invention can improve often subjected to external impact and the like equipment, for example, mobile telephone terminal or portable camera or impact resistance of the long-term reliability.

Although the preferred embodiments of the present invention and are described in the above description, it should be understood these examples are examples of the present invention, should not be interpreted as limiting. The within the spirit and scope of the invention is added, omitted, replaced and other modifications. Therefore, the present invention could not be considered as limited by the above described.