ETCH AND SIDEWALL SELECTIVITY IN PLASMA SPUTTERING

Etching processing, one or more electromagnet 2 with controlled steering ions argon strikes the a wafer at an angle (steer) is made in a plasma sputtering reactor. The present invention refers to in particular useful to reduce asymmetry sidewall, soft low-k inter-breaker useful in protected in interconnect level. Etching, liner layer (liner layer) is, for example barrier layer dual-damascene interconnects such via hole in structures the hole and the bottom and wall after deposition on copyright 2000.

Steering two 2 2 opposite of different sizes common plane of two DC current is supplied to magnet common axis or by power to or more coils one or 3 by supplying which can be effective in, at least or more coils one or said 3 the chamber 2 different to a central axis of the. support of the femur.

The argon ions etching in another aspect of the present invention different a wafer at an angle a steering to hit a 2 is divided to two phases.

Another aspect of the present invention as argon ion energy i.e., less than 65eV (self-bias) self-biased support power by reducing the copper for the metallization insulation barrier and is coupled to another end or tungsten tantalum on copper for includes selectively etching. 2 in the least one feature of the first, the barrier, the argon ions creates a much larger exposing the copper initially used energy 2000 the bottom portion of the via. Furthermore, the argon ions reduces the energy.

Of Figure 1 EnCoReII reactor (8), which is operable under a sputtering deposition mode already as well as of the deposited material on a wafer for etching a sputtering etching. operative mode. Alternatively, interconnected structure in different regions of selectively depositing thin to finally settle sputtering of deposition and sputtering and etching are performed simultaneously to can be selected is an operation condition. However having a larger hardness than the aforementioned and etching a sputtering deposition material the method, the aforementioned black diamond II or other soft deposition material such as low-porous soft k a causes problems in material. K low-soft sputtering any insulation and the insulating the pores also etching the semiconductor substrate is supplied to in enhance to high dielectric constant. Generally, carbon-doped silicon silicon dioxide is softer. As a result, low-k and a gate electrode material are deposited barrier insulating layer during etching preferably absolute is not exposed. Gung by selective etching and deposition disclosure method a soft low-k insulating layer when opened which resistance, however, brings problems with at least two, with the sole via floor trench (trench floor) between sidewall asymmetry is very low selectivities. Of the existing method method are, silicon insulation prior to step deposition final flash in static energy insulation to sputtering etching ion (energetic sputter etch ion) by exposing the heater, grew in to avoid these problems. K low-soft however breaker low-k sputtering etching lowers the breaker. The method by low- yearly paragraph Gung k which is not suitable for insulation, they are protected is necessary that sputtering during etching. Selectivity and between via trench sidewall asymmetry noise is removed from low-effect of insulation k inner excellent protection, it is necessary that described.

The described first selectivity. One dual-damascene structure (100) is shown as cross-sectional drawing in of Figure 2 drawing is. Insulating layer (102) etched in a complex dual-damascene hole has a bottom portion that has a narrow via (104) and the upper region is in (106) includes. The an important part of said structure, insulating layer (102) in upper portion of the reactor a flat area (108), via (104) bottom via bottom (110), the via sidewalls body (112), trench floor (114) and via (104) and a trench floor (114) (bevel) (116) the bevel of a corner is. Vertical patterned dual-damascene structure (100) trenches floor (114) near at a level insulating layer (102) in the etch stop layer not shown can be obtained by (etch stop layer). As in preferred metal copper via in one step (104) and trench-type capacitor and (106) which placed inside the via (104) through the underlying layer vertical interconnects and conductive features in addition which, forms a connection trench (106) to via other along to form a horizontal interconnect. However copper insulating layer (102) diffuses in so that a. tendency. Therefore, by carrying out an electroplating treatment is filled hole is copper as before from flooding so that, for example such as (bilayer) double layer Ta/TaN barrier layer (118) is (108) for including dual-damascene structure sputtering on the surface of wall and can be be suitably coated over the comprises isopropyl alcohol vapor and nitrogen gas. However, barrier layer (118) the vias bottom (110) is not formed on or at least very is formed thin the underlying conductive features and reducing a contact resistance and it is preferable that the. However barrier layer (118) trench floor (114) and the via sidewalls body (112) which needs to be in remaining in, preferably field region (108) in. must favorably. Trench floor (114) and inclined (116) the via bottom (110) largest selectivity to. viscosity for molding. Extended sputtering etching the vias bottom (110) deposited on used to remove TaN or Ta, etching trench floor (114) to expose insulation k low-on soft extruded rapidly and roughening at is eliminate. Furthermore, a high energy sputtering etching the insulator in the will degradation of pores of the support member, a.

Trench floor (114) on barrier layer thicker than (118) and via bottom (110) being thinner or the Image at a a barrier layer or non-existent (118) a preferred the selectivity preferably via bottom (110) to substantially without first depositing an barrier material may be preferably by, barrier material, and can from there or copyright 2000 by etching. The Gung of Figure 1 sputtering chamber (8) within patterned barrier layer (118) for forming are described.

Via bottom (110) in floor trench in canceling completely barrier layer (114) on barrier layer (118) to minimize removal of, with the sole via etch selectivity between floor trench ξ is to maximize the preferably, this area as and,

Here ER_γ the via at the bottom etching and the ER_τ is etch rate in floor trench. Trench etch also 2 reference to an activity such that a rate of area as, thereby,

Here η₀ (E) energy dependent ion sputtering yield and, Γ_T⁺ and ion flux on floor trench, Γ_T⁰. flux neutron on floor trench. Second variable low energy neutron exhibits deposition of metal atoms. Similarly, etch rate via area as and the receiver opens the mail,

Here, Γ_V⁺ and ion flux of the bottom the via, Γ_V⁰ for neutron flux which the via bottom, δ the via bottom portion that has a re-sputtered material recovery of is (recapture coefficient) constant, a via is. plurality of predetermined structures.

A faster etch selectivity, on the-flux neutron on floor trench neutron flux is obtained if a very high degree of compared can be,

Via ion flux on floor trench or on its bottom is obtained if very small compared to ion flux can be.

All of these flux are, representing flux reaching the each surface which, the neutron and of ions angular distribution is preferably selectivity is especially serves in made.

The nozzle in one associated with, which develops after via etched bevel or surface and associated with trench is etch rate of bevel regions structure of automobile. For neutron corner for neutron floor trench is high, typically at deposition rates smaller than corner of the deposition rates without due to is of the type which is exposed, for afforesting an incline from a high energy sputtering etch rate is high, typically at trench greater than etch rate sputtering structure of automobile. While, and the surface of a plane deployed is considerably smaller than that of a region floor trench region since the, instantaneous exposed via an inclined face resulting from an insulating material a large change constant the insulating layer will not result in problems is.

RF inductive power-free auxiliary magnets or of the existing method is sputtering reactor diode, high selectivity a response pulse used for DC power, support of the first electrode from a third bias power RF form allows optimization of the chamber pressure and an. Sufficient reactor diode of the existing method did not supply control. However of Figure 1 reactor (8), to be available at the additional inductive coupled RF RF sputtering power DC power of plasma is etched allows from being separated from generating.

Alternatively selectivity deposition selectivity can be acquired. Also Figure 3 shows a RF bias power according to sputtering deposition stage or coverage within a is a (net depositing)-deposition order. Plots on-deposition order at the bottom via (120) within a via a bias power is RF the ionized sputtering particles is shown that the urging a, thus deposition in biasing 0 rising from the smallest value to the road and for locating the bottom the via the creation of a high rising from the smaller portions of sputtering particles.. While, plot (122) the, inclined neutron and isotropic neutron is-deposition order in from sputtering particles but relatively high in biasing 0, the increase in bias sputtering particles ionized increase the amount of energy and therefore increase for afforesting an incline and reduce deposition order increase the sputtering etching is shown the.. In relatively high bias, sputtering etching aspects are the superior than sputtering deposition is formed. Cross RF bias point (124) in, via bottom coverage (120) comprises a rake face coverage (122) .the same. A rake surface relatively high RF cross-zone and its deposition selectivity, the via bias point (124) below the present.

RF bias power watt of Figure 4 a graph 300 millimeter wafer according to deposition selectivity. shown. Plot (126) depicted at the trench/via deposition selectivity plot (128) via an inclined face depicted at. that is always greater than that selected, the via. Therefore, neutron and ion resulting from deposition selectivity is less always a way that the slant than floor trench.

A graph of Figure 5, for example of the wafer mainly, a shifting element follows an argon ion sputtering etching in this etching step sputtering, such as RF bias power on. diagrammatically indicate the dependency of the etch rate. Plot (130) and diagrammatically indicate the etch rate in a rake surface, plot (132) is shown that the via etch rate at the bottom.. Since the geometry, etch rate inclined bottom via always tending etch rate greater than. Therefore, bottom via over contacts the inclined surface biasing RF etch rate of. does not provide advantage in the selectivity.

Applied to coil in particular RF selectivity chamber of Figure 1 EnCoReII RF power provides an additional control. 4 power and DC applied to coil RF drainage electromagnet array ED from flexible while the magnetic field further, deposition or etching selectivity to. not affecting the thermal stability of primary. Of Figure 6 a graph, target, according to RF coil and the receiving base applies power to. is shown that dependency selectivity etching. Plot (134) the user to select and purchase a desired bias RF the originally faster multivalent decrease smoothly reduces the. Plot (136) according to power RF applied to the RF coil for selectivity etching exhibits similar behavior. However, plot (138), an increase power target DC the selectivity etching according to. close to approximately linear increase. As a result, DC power of the most effective control interest only optimized RF coil power and. must mixed with bias RF. Plot graph of Figure 7 (140) to which it relates in a mixed with coil power RF bias and RF DC target power according to overall. shown selectivity etching. Entire etching selectivity peak near region (142) for operation is optimized for.

Furthermore, static energy selectivity etching selectivity material from the argon ions is enhanced. In including a float shown point of Figure 8, different yield as the argon ions and sputter tantalum and copper. Tantalum in soliton proparation energy low the argon ions a low sputtering-copper over. that experiences a larger increase selectivity. Low areas than about 65eV (146) that experiences a larger increase the selectivity in.. Therefore, under conditions copper, tantalum non-copper effectively. amplified to etching. Processing, of the existing method of the via etching tantalum sputtering tantalum is such that they open at bottom, then selected for the tantalum operation condition the copper to sputter switched useful in particular in step treatment 2. Harvest energy as argon lower during the and an etching phase two approaches is connected to the semiconductor layer.. In first scheme, RF coil power is 2kW and, a bias power is support RF is 250W. In second scheme, 4kW target power is DC, RF 2kW is coil power, a bias power is 700W RF support, and DC is 750W is coil power. The same selectivity copper for the metallization tungsten-based barrier even copyright 2000.

Sidewall asymmetry is etching and deposition selectivity problems exhibiting different from, the problem a different manner than a EnCoReII reactor can be non-volatile memory elements is considered. In Figure 9 cross-sectional drawing the dual-damascene structure (150) of the insulated and an etching phase provided ideal structure and the structure of Figure 2 (100) corresponding to.. Dual-damascene structure (150) an insulating layer (152) is formed through the via (154, 156) includes, each insulating within the overlying conductive feature via bottom (158, 160) has. Least a predetermined amount of the via sidewalls body (162) having a very high aspect ratio exhibits and step. Via (154, 156) comprises an elongated, and relatively region is (164) is interconnected by, this has floor (166) has a. Complex via structure (150) which different etching by a publicly known method can be, for example the trench floor (162) that is yet adapted to the insulating layer (152) formed in an intermediate etch stop layer (intermediate etch stop layer) according to two photolithographic (photolithigraphic) includes. Via (154, 156) and trench-type capacitor and (164) having the overall via structure (150)-operates with an electric plating copper (electroplating copper) and thin copper seed layer (copper seed layer) in the sequence a single sputtering depositing an can be filled by copper in, chemical mechanical polishing (chemical mechanical polishing) followed via structure (150) fill in the cavities insulating layer (152) at the top field region (168) over a dual-damascene structure (150). removing copper the additional outward. The, insulating layer (152) via in (154, 156) connection structure and vertical interconnects through trench (164) through a horizontal interconnect structure is formed.

For example not shown in Ta/TaN or Ta barrier layer dual-damascene structure (150) before copper onto the copper-seeded surface in needs to be coating, copper is insulating and disconnection prevents diverging. Barrier layer, in particular nitrogen portion the vias bottom (158, 160) but is preferably removed from, barrier a dual-damascene structure (150) outer insulating layer (152) surface of upper (168) and sidewall body (162), trench floor (166) increase volume and. important.

Sputtering of deposition and sputtering and based etch balance by dual-damascene structure (150) different within a portion of the barrier layer for selectively forming a Gung good measures a disclosure by a central-to-edge (center-to-edge) but the equalization, in particular the edge of the wafer in a hole dual-damascene near sidewall in etching and different asymmetry is observed, that is causing a been. All barrier nitrogen via near edge (156) to be removed from the, need increase the etching time, i.e. aggressive (aggressively) in surface or over-etching (over etch), it is necessary that. Such as to the cross-section of Figure 10, via hole near wafer edge (156) sputtering etching step during etching over-of beveled bottom portion (172) which deploy a, which remains therewithin is nitrogen, barrier is employed further eliminating. Via bottom (172) in the first the underlying conductive features in an as such it is not. However, over etching trench floor (166) of fluids from and to a field region (168) from inputted into barrier is tendency for removing, its the underlying low-k. sacrificial oxide layer. Furthermore, (facet) (174, 176) plaque seat (referred to as output efficiency are increased) the at their corners due to geometry exposed trench floor (166) formed on the sides of the matrix polymer and tends to. plaque seat but be increased should is controlled range. However plaque seat near-edge (176) relatively greater than was observed. plaque seat near-edge (176) via near-the edge (156) is checked below, via (156) is tapering (tapering) the upper part via a wide area the critical dimension (CD; critical dimension) is. have a large impact. Radially asymmetric sidewall thus the 0s are the problem, , it is necessary that minimize same. At least, is considered a zero -0s radially asymmetry sidewall, it is necessary that.

Low-k insulating layer (152) of parts exposed trench floor (166) which from , copper which are deposited the later covered by engraved pattern the barrier to stay late at. is necessary. Hand, via and reducing a contact resistance barrier layer at the bottom it is preferable that the removed to. However, conventional floor trench measures (166) clears the barrier in low-k of an insulating material for roughening surface of the rear side of the main unit. Therefore, trench floor (166) the liner (liner) therefore via bottom (172) is preferably removed by using a display device..

Also 10 ion sputtering symmetry laterally non-shown in, in particular sputtering in this etching step used argon sputtering can be described directional that of ions. Sidewall electromagnet array of Figure 1 (72) is ion sputtering the central region of the shroud when a user to define a, electromagnet array (72) below a the inner direction (180) along a. tendency to follow the path. Static ions inner and comprised of randomly oriented energy, via bottom (172) via near-edge to provide inclination of (156) and the distal the bottom of preferably etching an inner corner. Furthermore, the near-edge plaque seat (176) is connected to the semiconductor layer. tendency preferably etching.

In one aspect of the present invention, sputtering etching ion this direction (182) having dual-damascene structure (150) to which that it is hypothesized, this are shown in the cross section in Figure 11, on the wafer surface is substantially perpendicular of via bottom (184, 186) plaque seat of the same size and (188, 190) provides.

Hand, at least some cases, wafer edge toward the outside is indicated as shown cross section of Figure 12, correction wherein ionic anisotropic (192) so that it can be accessed by which does not is preferably, also the control signal to voltage via near-by press molding only after flat plate 10 (152) and a larger center near- plaque seat (196) in beveled bottom portion (194) and a small edge near- plaque seat (198) as it is intended to provide a sidewall asymmetry.

Establishing an optical fiber at a side in background art, of Figure 1 electromagnet array (72) the upper the inner magnet (TIM; top inner magnet) (74), upper outer-side magnet (TOM; top outer magnet) (76), lower inner magnet (BIM; bottom inner magnet) (78), and lower outer-side magnet (BOM; bottom outer magnet) (80) be at 500. Drive current vector TIM/TOM/BIM/BOM. can be represented by. Gung by electromagnet a bottom portion that an etching step disclosure (78, 80) applies current to opposite the same as the variable bit rate, this is in particular current 0/0/19 /-19, also magnetic field distribution as shown in 13 (200, 202) provides. Such a magnetic field distribution, the same shaft, and height of the light -2 but different radius positioned on the opposing magnetic a tall or different radius of 2 opposing doughnut magnetic field coils respectively drive the actuator depending on. As a result total magnetic field very quickly silicon carbide body (12) the chamber the ion and plasma which spaced apart inner sidewall body (12) or shield (36) tools, thereby the upper cover is leakage to, the preferred inner the chamber the ion and plasma as equal as is constrained as density plasma of. However strong and sharpen focused repulsive magnetic field toward inwardly with respect to the ion (repelling field) a component. it's believed that inlet.

Levels of current one in the embodiment of the present invention is reduced in the upper inner electromagnet (74) applied to the shown in 14 also provides magnetic field, magnetic field on the prior art (200, 202) and an additional donut magnetic field distribution (204) includes. In one in the embodiment BIM current TIM is opposite directions relative to current, and which have a current vector-is -19/19/1.25/0. Establishing an optical fiber at a side, lower electromagnet (78, 80) the top electromagnet (74, 76) about 2 times a value of an electric current to winding (turn) since the reverse link has a higher direct their magnetic field which is subsystem of user indicative of the intensity of the or not. TIM electromagnet (74) the magnetic field provided by electromagnet BOM and BIM (78, 80) of a tall magnetic additional at a different height bipolar berry (204) while the, TIM magnet (74) simple bipolar market BIM and BOM electromagnet (78, 80) non-parallel wall chamber compared to vector sum bipolar funeral (12) inwardly into the. away slowly. Total magnetic field the chamber wall (12) or shield (36) near a central axis (14) parallel to the expansion is along a direction of the first sharp is not.

Furthermore, also the directivity of ions as shown in 15, electromagnet array (72) and rotations as small as magnetron (50) of sum of magnetic means including magnetic means provided by distribution of (B) magnetic field (212) magnetic domain of null (magnetic null) (210) has primarily depends on the position of. Null (210) a wall chamber 15 as shown in (12) if extremely low along, wafer magnetic field (32) which inclined outside from an edge of a, as illustrated at in Figure 16 cross-sectional drawing as the incident ion this direction (180) thereby sliding tubes directly via wafer edge (156) is hit a. Gung of electromagnets 0/0/19 /-19 in a this effect can be produced by the current. On the other hand, as shown in also 17, magnetic field distribution of (B) (216) magnetic null (214) the chamber (12) along the wall above, distribution (216) the wafer (32) of which inside from the inclined, as as illustrated at in Figure 18 cross-sectional drawing the incident ion this direction (192) along the inclined to the outside from the. Such magnetic field distribution (216) or by a combination of current the TIM/BIM/BOM TOM/BIM/BOM BIM/BOM or by a combination of current current by the unbalance of the can be produced.

The shingles chamber axis (14) having coils pole pieces positioned along the steering can multi-pole magnetic field. Therefore, is introduced into the ion stromal plus are oriented and may for instance be controlled, of Figure 11 speed of direction normal incidence, reduces the asymmetry sidewall.

Tantalum linear in a combined sputtering of deposition and sputtering and etching of the scheme outweigh range is abstract in table 1 below.

The power level should standardised 300 millimeter wafer. Electromagnet current ion is one of silver, copper is electromagnetic coil surrounding a central axis (14) is referred to current direction about. Such measures, single Ta barrier layer are in accordance. Nitrogen while sputtering tantalum added in the chamber if an applied to a another step TaN/Ta layer of a double layer is can be produced. Table 2 table 1 range of specific from abstract a in order to expose partially sidewalls.

Such measures, during etching by only use of current TIM during etching as well as higher than target power, and low bias power than during deposition and etching during etching Gung in increased RF coil power is high resolution measures preferred.

3 table the room of other ranges are in is abstract.

Such measures non-current TIM in that current TOM fact that the coded data in table 1 is divided into. From wall the chamber the coil is supplied with the high current TOM far to TIM current and. must be high than I similar function.

Compared to current BOM and BIM metal ion is one of silver, current TIM sidewall asymmetry relative to reduce that it has been discovered that the less important.

Ion steering using the argon ions sputtering etching is described, primarily in reference. However, ion steering, tantalum in as if is positioned in the high metal ions can be applied even sputtering deposition.

The present invention refers to tantalum barrier deposition described for but, [...] , [...] /tantalum, tungsten, titanium and barrier material additions of other gases such as nitrogen compounds the present invention even can be is used. Furthermore, plurality of same angle considering and sidewall ratio symmetry copper seed layer sputtering deposition but can also be applied to, here very thin continuous side wall preferably local version of the identifiers associated with body. Copper sputtering reactor two or more auxiliary. are able to adopt the electromagnet. In particular area in wafer to efficiently which is turned on to carry current electromagnet the sidewall body is controlled to provide coverage. Very high the disproportionation body sidewall of deposition rates, alters the current electromagnet can be obtained in, alternatively inwards the outer angled magnetic field provides to the wafer surface, the copper ion is price a sidewall continuously. A relatively high copper of a copper ion portion can be sputtering, the sputtering deposition direction control is very greatly increased.

Therefore, a thin layer the present invention refers to complex or applied the barrier material of material, such as copper, and in a composite structure is geometry of a different material from that of sputtering/etching characteristics of provides better control.