Device for mounting components on a substrate.

[0001] the invention concerns a device for mounting components, typically electronic or optical components, especially semiconductor chips and flip chip, on a substrate. The mounting is designated in professional circles as bonding process or equipment process.

[0002] devices of this kind are used in particular in the semiconductor industry. An example of such devices the bonding or picking & machines are square, with components in the form of semiconductor chip which, micromechanical and micro-optical components, and the like are deposited on substrates such as leadframe, printed circuit boards, ceramics etc and bonded. The components are received at a recording site in a bonding head, in particular sucked, risks to a substrate at an accurately defined position and deposited on the substrate place. The bonding head is part of a picking and Place system, allowing movements of the bonding head in at least three spatial directions. So that the placement of the component can be exactly on the substrate layer, the exact position of the bonding head must be both from component with the positioning axis of the bonding head taken as determined the precise position of the substrate place also.

[0003] from the publications cost 449,481, us 5,878,484, where such devices are known and EP 1,916,887 2004, 064, 472, which are used for two vertically rotated 45° mirror, the underside of the component on a map to camera, so that as the position of the component with the positioning axis of the bonding head can be determined. A device is known from EP 2,373,145, a mirror and a penta prism used in the, the underside of the component on the camera for imaging. In these devices the optical axis of the camera is parallel to the axis of the bonding head positioning. Wherein the position of the component is only EP 2,373,145 device, determines the position of the substrate but not square.

[0004] devices used industrially in the younger time usually two cameras are used, namely a substrate arranged in or below the plane, determining the position of the component camera for upward and above the substrate plane arranged, camera for determining the position of the substrate place downward. An important disadvantage of these devices is, that the bonding head must first receiving location in or below the plane of the substrate to the camera and then further drive arranged for substrate place, which means a detour often.

[0005] the invention is based on the, to develop a device, for determining the position of the component and the determination of the position of the substrate place needed only a camera, a simple optical structure has little place and claimed.

[0006] said task is solved by the features of claim 1st invention advantageous configurations emerge from the dependent claims.

[0007] the invention is explained in more detail below with reference to embodiments and with reference to the drawing. The Figures are not drawn schematically and scaled.

[0008]

Figure. 1 and 2 show two snapshots of a device according to the invention for mounting bauele -

menten, and

Figure. 3 and 4 show an alternative implementation options of individual optical deflection systems.

[0009] the Figure. 1 and 2 schematically show two snapshots in side view a device according to the invention for mounting components on a substrate 3 2 places the substrate 1. The components are typically electronic, mechanical or optical components (micro -) micro, especially semiconductor chips and flip chip. The device comprises a support 4 for the substrate 3, a picking and Place a system with a bonding head 5 6, a single camera 7, a first optical redirection system 8, a second optical redirection system 9, 10 a first light source, a second light source and a third light source 11 12. The bonding head 6, the first optical redirection system 8, the camera 7 and the second light source are mounted on a common carriage 11 13. The second optical redirection system 9 disposed on the apparatus is stationary. 3 the substrates normally have plurality of substrate locations. The term "substrate place 2" is hereinafter usually place person to understand substrate, the field of view of the camera is in 7, wherein said optical path space from the substrate through the first optical redirection system for camera 2 7 8 extends therein and is deflected at least once.

[0010] the surface of the support 4 for the substrate defining a substrate plane and Place the picking system of the 14th 3 5 comprises at least three drives, the carriage to move in three directions in space 13, namely in two directions, parallel to the substrate plane 14 extend, and in a direction designated here as Z-direction, perpendicular to the substrate plane 14 extends. The bonding head 6 has a gripping axis 15, the Z-direction.

[0011] the camera 7 and 8 together form the first optical redirection system a first imaging system, enabling, a picture of the substrate receiving space 2, on which the component 1 is to be mounted. The camera 7, the first optical redirection system and the second optical redirection system 8 9 together constitute a second imaging system, enabling, a picture of the underside of the bonding head 6 1 held by the receiving component.

[0012] the picking and Place a system 5 is arranged, with the bonding head 6 are each a component 1 at a recording site on a substrate 2 receive and place to place. So that a highly accurate positioning is possible, on the one hand the camera takes a picture of the underside of the component 1 and on the other hand 7 a picture of the substrate 2 on site, on which the component 1 is to be placed.

[0013] 8 serves the first optical redirection system, the optical axis 16 of the camera 7, laterally offset from the axis of the bonding head 6 in the Z-direction 15 gripping, as optical axis 17 closer to the grip axis 15 of the bondhead to 6. The object-side optical axis of the first imaging system 17 extends a distance d for first optical deflection system 8 thanks to the gripping axis 15 of the bondhead 6, is significantly less than the distance between the gripping axis 15 of the bonding head 6 and the optical axis 16 of the camera 7.

[0014] the second optical redirection system 8 and 9 the first optical redirection system acting together and bring the underside of the head 6 of the bond held 1 component of vision of the camera 7, as long as the bonding head 6 in a predetermined working area above the second optical deflecting system is 9.

[0015] so that the camera 7 both the bottom of the member 1 and the substrate a sharp picture space 2, on which the component 1 is to be placed, can receive, the optical path of the beam paths of the first imaging system must and the second imaging system long be as equal as possible. Adjusting the length of the beam paths of the pick 13 effected by moving the carriage and Place system 5 in the Z-direction. The device is therefore being programmed, for taking a picture of the component 1 the carriage 13 in the Z direction in a predetermined height H I above the substrate plane 14 via the second optical redirection system to move 9, so that the underside of the component 1 at least during its travel through the second optical redirection system 9 in the plane of the camera 7 is sharpening, 7 during a displacement of the component so that the camera 1 a sharp picture can receive the bottom of the member 1, and for receiving an image of the substrate place the carriage to a predetermined height H 13 2 each₂ on raising the substrate plane 14, so that the substrate 2 in the plane of the camera 7 is place sharpening, 7 a sharp picture of the substrate 2 so that the camera can receive site. The two height H I and is H₂ are of such dimensions, that the optical length of the optical path between the bottom of the member 1 7 and the camera and the optical length of the optical path between the substrate 2 and the camera space 7 are identical in size, so that the underside of the component 1 or the substrate 2 place either in the plane of the camera 7 is sharpening. As from the Figure. 1 and 2 show, is H₂ > |- HOURS.

[0016] the device can be programmed so, first places a substrate 3 of each of the substrate 2 and then receive a picture captured the component on the substrate 2 of the substrate 1 to 3 mounting locations. But it can also be programmed, wherein each mounting operation the bottom of the member 1 and then a picture a picture of the associated substrate receiving space 2.

[0017] the Figure. 1 shows the device in the state, in which the carriage 13 in the predetermined height H₂ being located at a position, in the field of view of the camera in place a predetermined substrate 2 is 7, so that the camera 7 a sufficiently sharp image space can accommodate this substrate 2.

[0018] the Figure. 2 shows the device in the state, in which the carriage 13 in the predetermined height H-I and within the working area of second optical deflecting system is 9, so that the underside of the component 1 in the field of view of the camera is 7, so that the camera can receive a sufficiently sharp image 7 the bottom of the member 1.

[0019] according to a first embodiment the first optical redirection system 8 comprises a prism and a mirror 18 19. The deviating prism is a triangular body 18 in cross-section, the one of the substrate plane in the Z-direction outgoing light beam 20 21 22 and reflected on two surfaces. The lower surface 22 of the triangular deflecting prism 18, 20 at the light beam undergoes the second reflection, the 14th plane parallel to the substrate 21 the second surface, the first reflection on the light beam 20 undergoes, is mirrored and closes with the lower surface 22 a a predetermined angle α. The angle α is so determined, that the light beam totally reflected at the reflection at the lower surface 22 is 20. So that the total reflection occurs, the angle α must meet the snelliussche refraction law:

α < 90° - ASIN (s/s (air) (prism 18))

the refractive index of the air (air) wherein n and n denotes the refractive index of the material (prism 18), from which the prism is 18.

[0020] the second optical redirection system according to a first embodiment 9 comprises a symmetrical deflection prism 24, from the underside of the component 1 in the direction of the gripping the outgoing light beam reflected three times 15 axis 25, parallel to the gripping axis deflection prism 24 until it again leaves the first optical redirection system impinges on 15 and 8. The light source 10 is on the one side of the deflection prism 24 disposed below the deflecting prism 24. The deviating prism is an isosceles triangle in cross section 24, with three faces 26-to-28, whose angle beta is chosen such, that the light beam is totally reflected on the upper surface 25 26. The angle β must therefore the condition

beta - ASIN < 90 ° (s/s (air) (prism 24))

meet.

[0021] thanks to the total reflection mirror coating the upper surface 26 is not necessary, so that the reflected light in the deflecting prism 24 penetration on the component 1, inside at all three surfaces 26-to-28 reflected, from the deflection prism 24 emerge again and then using the first optical deflection system for camera 7 8 can be conducted.

[0022] the surface 27 is advantageously performed mirrored. If the light source 10 for illuminating the underside of the component 1 held by the bonding head is present, then the surface 28 is not free, but another triangular body 29 forms a beam splitter with a portion of the deflecting prism 24. The beam is shared on the surface 28, for example by frustrated total reflection as usual. The polarizer layer 28 can be carried out but also as polka-type are first acting surface. A polka-type are first is a pattern, the reflection points is arranged from array-wise.

[0023] the first optical redirection system 8 comprises, as in the Figure. 3 and 4 is represented, according to a second embodiment instead of the deflecting prism 18 a mirror 23, the includes an angle with the vertical. The footprint is larger than the footprint of this embodiment first embodiment, with the result, that the distance d between the gripping axis and the optical axis 17 6 15 of the bondhead is greater than in the first embodiment, because the required material thickness of the mirror 22 already increased the distance d. The mirror 19 and 23 be able to 45 °, 45° or less than 45° but also more than be inclined to the vertical. But then a larger space requirement of the mirror 19 resulting downward toward the substrate plane 14 or 23 of the mirror in the direction of the bonding head 6.

[0024] the second optical redirection system 9 comprises, as in the Figure. 3 and 4 also is represented, according to a second embodiment a cube beam splitter 30, 31 a penta prism and, optionally, an optically transparent body 32, preferably between 30 and the penta-prism beam splitter cube seamlessly 31 is arranged. The light beam outgoing from the underside of the component 1 in the beam splitter cube is 25 to 30 deflected 90 °, in the penta-prism 31 at two surfaces while a further 90° deflected reflected total, so that the light beam emerging from the penta-prism 31 parallel to the gripping axis parallel to the optical axis 6 of the bondhead 15 and 16 extends the camera 7. The body 32 and the optical path of the light beam 25 prevents shortened both on leaving the beam splitter cube reflections and upon entering the penta-prism 30 31, is inserted between these two elements when seamlessly and consists of the same material.

[0025] the optical components of the two deflecting systems 8 and 9 are of a transparent material, preferably made of glass or transparent plastic having a relatively high refractive index.

[0026] the light sources for illuminating the bottom of the member 10 and 12 serve 1. The light source 10 is preferably below the beam splitter cube 30 arranged. The beam splitter cube 30 thereby serves for coupling light emitted by the light source 10 as well as to couple out the light reflected on the underside of the component 1. The light source 10 illuminates the underside of the component 1 in a coaxial manner to the optical axis 16, 1 in particular to components with a smooth, reflective underside to illuminate optimally, while the light source 12 as a side light for the optimal illumination components 1 with a rough, diffusely scattering underside is formed.

[0027] the light source for illuminating the substrate 11 serves 2 space. The light source 11 preferably comprises about the optical axis of the first imaging system on all sides 17 arranged lighting means, such as a side light illuminating the substrate to be illuminated space. It can also comprise a coaxial illumination.

[0028] the camera 7 can the picture 1 the bottom of the member during the travel of the bonding head 6 via the second optical either redirection system 9, i.e. without stopping, receiving, or the device can the bonding head 6 above the second optical deflecting system 9 stopping, receive the picture.

[0029] in all of the embodiments can the mirror 19 and the camera are arranged such omitted for 7 (twisted), that its optical axis coincides with the direction 16, the light beam after reflection on the mirror or prism 20 18 23 has.

[0030] the invention offers at least the following advantages:

It is only a single camera - necessary, both the exact position of the bonding head and the exact position of the substrate taken from component to determine location.

The first optical redirection system shifts the optical axis of the camera - closer to the gripping axis of the bonding head and thus increased working range of the machine.

The first optical deflection system has a reduction in the optical path length - from the bottom of the component to the camera for adjusting the sharpening result thus reducing the level of the height difference H I and H is necessary camera₂ .

The second optical redirection system - the bottom of the member enabling an accommodation during the journey, without the bonding head must be encouraged. The bottom of the member is stationary because the picture this apparently, as long as the component in a predetermined operating range of the second optical deflecting system is.

The first optical deflection system is integral with the bonding head - connected, the second optical redirection system is stationary on the machine. Displacements of one or other or parts thereof during the bonding process are thus deflecting system unnecessarily.

- The height H I and is H₂ the choice of the geometry and the material of the element 24 can or the elements 30, 31 and 32 are adapted to the specific requirements of the mounting device.