CN1722399A - Method and apparatus for mapping a position of a capillary tool tip using a prism - Google Patents

Abstract

A system is provided for use with a wire bonder and an optical imager to determine the position of a wire bonding tool. The system includes a prism positioned beneath the optical imager and the wire bonding tool. The system also includes at least one lens positioned between the prism and the lower portion of the wire bonding tool along the first optical axis. The at least one lens and the prism define an object plane between the at least one lens and the lower portion of the wire bonding tool. The at least one lens is located between the prism and the optical imager along the second optical axis. The at least one lens and the prism define an image plane between the at least one lens and the optical imager.

Description

Method and apparatus for mapping the tip of a capillary tool using a prism

This application claims priority to US Provisional Patent Application 60/581,476, filed June 21, 2004, the contents of which are incorporated herein by reference. This application is a continuation-in-part of U.S. Patent Application No. 10/458535, filed June 10, 2003, which is a divisional of U.S. Patent Application No. 10/131873, filed April 25, 2002, parent filed in 2004 Published May 4, 2002, Patent No. 6729530, the parent case is a continuation-in-part of U.S. Patent Application No. 09/912024, filed July 24, 2001, which was published July 2, 2002, Patent No. for 6412683.

technical field

The present invention generally relates to a method and apparatus for mapping the position of a capillary tool tip using a prism. More specifically, the present invention relates to the use of prisms, such as corner cube prisms, to account for errors in joint position due to deviations in position (eg, X and Y positions) of the capillary tool tip at different Z heights.

Background technique

The manufacture of electronic components such as integrated circuit chips often requires alignment checks of devices at various stages of the manufacturing process. This alignment inspection step often utilizes a vision system or image processing system (such as a system that captures an image, digitizes it, and completes the image analysis using a computer) to line up the manufacturing machine for proper placement and/or alignment of components and bonding wires.

In conventional systems, post attach inspection is employed to determine whether a change in the position of the manufacturing machine is appropriate to affect proper placement and/or attachment of the bond wire. Also, these conventional systems typically compensate for misalignment after such improper attachment occurs, thereby negatively impacting yield and throughput. These conventional systems have the additional drawback of not being able to easily compensate for variations in bonding position due to deviations in the X and Y position of the bonding capillary tool tip when it contacts the device being bonded, further impacting device yield and negatively impacting device yield. significantly affect manufacturing time.

Fig. 11 shows a conventional image system. As shown in FIG. 11 , the conventional system includes two imaging devices, a first imaging device 1104 placed below the workpiece plane 1112 looking up at the object and a second imaging device placed above the workpiece plane 1112 looking down at the object. A disadvantage of these conventional systems is that, in addition to using more than one imaging device, they cannot easily compensate for changes in the system due to, for example, temperature changes.

Furthermore, when the capillary tip contacts various devices at different heights Z, errors in engagement position due to their deviations in X and Y positions cannot be adequately accounted for in conventional systems. The present invention aims to fill this gap in conventional systems.

Contents of the invention

According to an exemplary embodiment, the present invention provides a system for use with a wire bonder and an optical imager to determine the position of a wire bonding tool. The system includes a prism disposed beneath the optical imager and the wire bonding tool. The system also includes at least one lens positioned between the prism and the lower portion of the wire bonding tool along the first optical axis. The at least one lens and the prism define an object plane between the at least one lens and the lower portion of the wire bonding tool. The at least one lens is located between the prism and the optical imager along the second optical axis. The at least one lens and the prism define an image plane between the at least one lens and the optical imager.

According to another exemplary embodiment of the present invention, a method of mapping at least one of an X-axis and a Y-axis position of a tip of a capillary tool is provided. The method includes receiving a first image of a capillary tool tip at a first Z-axis position in an optical imager. The method also includes receiving a second image of the capillary tool tip at a second Z-axis position in the optical imager. The method also includes using the received first image and the received second image to determine (1) the difference in X-axis position or (2) the Y-axis of the tip of the capillary tool from the first Z-axis position to the second Z-axis position at least one of the positional differences.

According to yet another exemplary embodiment of the present invention, there is provided a method of measuring an error introduced due to angular variation of an optical system having a prism when using a wire bonding machine. The method includes determining a first crosshair position on a first reticle disposed at an object plane of the optical system. The method also includes determining a second crosshair position on a second reticle disposed at the image plane of the optical system. The method also includes determining a deviation between the first crosshair position and the second crosshair position to measure the error.

According to yet another exemplary embodiment of the present invention, there is provided a method of determining a position error of a wire bonding tool as the wire bonding tool moves along the Z axis using an optical imager. The method includes receiving a first image of at least a portion of the wire bonding tool at a first Z-axis position in the optical imager, and providing the first image to a processor. The method also includes receiving a second image of at least a portion of the wire bonding tool at a second Z-axis position in the optical imager, and providing the second image to a processor. The method also includes determining a position error between the first and second positions.

These and other aspects of the invention will be elucidated below with reference to the drawings and description of exemplary embodiments of the invention.

Description of drawings

The invention is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, in accordance with common usage, the various features in the drawings are not drawn to scale. On the contrary, the dimensions of various features are intentionally enlarged or reduced for clarity. Included in the accompanying drawings are the following figures:

Figure 1 is a perspective view of an exemplary embodiment of the present invention;

Figure 2A is a side view of an imaging trace according to a first exemplary embodiment of the present invention;

Figure 2B is a side view of an imaging trace according to a second exemplary embodiment of the present invention;

Figure 3 is a perspective view of an imaged trace according to an exemplary embodiment of the present invention;

4A and 4B are perspective and side views, respectively, of an exemplary embodiment of the present invention;

Figure 5 shows the telecentricity of an exemplary embodiment of the present invention;

6 is a detailed view of an exemplary retroreflective corner cube offset tool according to the present invention;

7A-7C illustrate the results of tilting about the apex of the rectangular prism of the exemplary imaging system;

8A-8C illustrate the results of tilting about the X-axis and Y-axis of the exemplary imaging system;

Figure 9 is a side view of an imaged trace according to a third exemplary embodiment of the present invention;

10A-10D are various views of a fourth exemplary embodiment of the present invention;

Fig. 11 is an image system according to the prior art;

12A-12F are illustrations of a fifth exemplary embodiment of the present invention;

13A-13D are different views of a sixth exemplary embodiment of the present invention;

Figure 14A shows a portion of an exemplary apparatus for mapping the X and Y position of a capillary tip as it moves along the Z axis;

Figure 14B shows an image of the advancement path of the capillary tip at several exemplary heights Z around a specified location;

FIG. 15A shows a portion of an exemplary device for determining a deviation in a displacement position of an optical axis by using two crosshairs; and

FIG. 15B shows photographic images of the initial and final positions of the reticle as a joint position error detected by the system.

A detailed description

The entire disclosures of U.S. Patent Application No. 10/458,535, filed June 6, 2003, and U.S. Patent Application No. 09/912,024, filed July 24, 2001, are hereby expressly incorporated by reference in their entirety as if fully incorporated Clarify the same.

It is an object of the present invention to measure and correct positional errors of the capillary tip at different Z positions introduced by deviations in position X and Y.

According to certain exemplary embodiments, the present invention relates to methods and apparatus for mapping the X and Y position of a capillary tool tip as it moves along the Z axis using a rectangular prism offset tool. The wire bonder's optics, combined with the rectangular prism offset tool, map the X and Y position of the capillary tip as it moves along the Z axis.

According to another exemplary aspect of the present invention, the system determines the deviation in the angle of the optical axis by using two reticles. The first reticle is arranged on the image plane (that is, the object plane of the optical system), the second reticle is arranged on the object plane, and is imaged on the image plane via a rectangular prism device.

According to another exemplary aspect of the invention, a wire bonder optical system includes low magnification and high magnification optical elements including lenses and a camera and image processing system. The image of the capillary tip is formed on the image plane of the wire bonder optical system, and then processed by the image processing system. Thus, the imaging system acquires and processes images of the capillary tip at each specified height Z to determine its X and Y position. Thus, joint position errors due to deviations in the X and Y positions of the capillary tip when the capillary tip comes into contact with respective devices of different heights Z can be corrected.

According to yet another exemplary aspect of the invention, the system is used with a ball joint during normal operation to improve jointing by correcting errors due to deviations in X and Y positions of the capillary tip as height Z varies. The accuracy of the position. Joint position accuracy is also improved by allowing correction of errors due to variations in optical axis angle.

Using an optical system consisting of a wire bonder, a rectangular prism offset tool, and a suitable illuminator, the X and Y position of the tip of the wire bonder capillary can be mapped as it moves along the Z axis. By determining the change in position of the crosshairs on at least one reticle, errors introduced by changes in the displacement position of the optical system can be measured. In an exemplary embodiment, one reticle is placed on the image plane of the optical system and the other reticle is placed on the object plane and imaged at the image plane via a rectangular prism offset tool.

Referring to Figure 1, a perspective view of an exemplary embodiment of the present invention is shown. The system is included in a wire bonding machine 100 and employs a rectangular prism 106 (ie, corner corner 106) having multiple internal reflective surfaces (best shown in FIG. At or below plane 112A (object plane 112A is shown in FIG. 2A and is part of plane 112 shown in FIG. 1 ).

In an exemplary embodiment, the rectangular prism offset alignment tool 109 (comprising the rectangular prism 106 and the lens elements 108, 110) has a total of three internal reflective surfaces 218, 220, and 221 (best shown in FIG. described below). In another exemplary embodiment, rectangular prism 106 may have multiple total internal reflection surfaces. For example, rectangular prism 106 may be formed from or include fused silica, sapphire, diamond, calcium fluoride, or other optical glasses. It is to be noted that optical performance glasses such as BK7 manufactured by SchottGlass Technologies of Duryea PA may also be used. Note also that the material of the rectangular prism 106 can be selected to have maximum transmission relative to the desired operating wavelength.

An optical imaging unit 102, such as a CCD imager, a CMOS imager or a camera, is installed above the image plane 112B (the image plane 112B shown in FIG. 2A is a part of the plane 112 shown in FIG. A cornercube offsetalignment tool 109 receives an indirect image of the joining tool 104. In another exemplary embodiment, a position sensitive detector (PSD), such as manufactured by Ionwerks Inc. of Houston, TX, may also be employed as the optical imaging unit 102 . In such an embodiment, the PSD can be used to record the position of the spot of light reflected by the bonding tool 104 when, for example, an optical fiber is used to illuminate the hole in the bonding tool 104 . It should also be considered that the PSD can be a quad cell or bi-cell detector, as desired.

In an exemplary embodiment, the focal point of the imaging system (coincident with imaginary plane 211 shown in FIG. 2 ) is located above the bottom surface of rectangular prism 106 (shown in FIG. 2A ). Additionally, the exemplary embodiment includes two preferably identical lens elements 108, 110 at or below the object plane 112A and image plane 112B. Another exemplary embodiment, shown in FIG. 2B, includes a single lens element 205 positioned below plane 112 and coincident with optical axes 114, 116 (shown in FIG. 1 ). Hereinafter, the combination of the right-angle prism 106 (ie, corner cube) and the lens elements 108, 110 (or lens element 205) is referred to as the assembly 109, the right-angle prism offset tool 109, and/or the right-angle prism offset alignment tool 109 .

The image plane of the rectangular prism shifting tool 109 comprising the lens elements 108 , 110 coincides with the object plane 112B of the optical imaging unit 102 . In other words, the image planes of the rectangular prism 106 and lens elements 108, 110 are aligned with the bonding tool 104, which also lies within the object plane 112A. In an exemplary embodiment, the lens elements 108, 110 (or 205) preferably have a unitary magnification factor. The first lens element 108 is arranged on the first optical axis 114 between the bonding tool 104 and the rectangular prism 106 . The second lens element 110 is substantially in the same plane as the first lens element 108 and is arranged on a second optical axis 116 between the optical imaging unit 102 and the rectangular prism 106 (see FIG. 1 ). In an exemplary embodiment, the first and second optical axes 114 and 116 are substantially parallel to each other and spaced apart from each other, depending on specific design factors of the bonding machine 100 . In one exemplary embodiment, the distance 118 between the first optical axis 114 and the second optical axis 116 is approximately 0.400in. (10.160mm).

Figure 2A is a detailed side view of an imaged trace and illustrates the general concept of imaging in an exemplary embodiment of the invention. In FIG. 2A, exemplary light traces 210, 214 are separated for clarity to account for the relative immunity of the resulting image due to position changes. Because the lens elements 108, 110 act as single magnification repeaters, the image points are also separated by the same distance. Figure 2A also shows how changes in the position of the bonding tool 104 are compensated for. For example, once conventional methods are employed to accurately measure the distance between the imaging unit 102 and the bonding tool 104 (shown in FIG. 1 ), the present invention can compensate for changes in the offset position 222 of the bonding tool 104 due to system variations. The position of the bonding tool 104 can be accurately measured because the rectangular prism offset tool 109 images the bonding tool 104 onto an image plane 112B of an optical system (not shown in this figure).

The reference position of the bonding tool 104 is shown as a reflected ray traveling from the first location 202 along the first optical axis 114 (shown in FIG. 1 ), constituting a direct image from the first location 202 through the first lens element 108 Beam 210. Direct image beam 210 continues along first optical axis 114 where it passes through top surface 226 of rectangular prism 106 onto first internal reflective surface 218 . The direct image beam 210 is then reflected to a second inner reflective surface 220 which in turn directs it to a third inner reflective surface 221 (best shown in Figure 3). Next, direct image beam 210 returns through top surface 226 of rectangular prism 106, forms reflected image beam 212 along second optical axis 116 (shown in FIG. 1 ), and passes through second lens element 110 to image plane 112B. Reflected image beam 212 is detected by image unit 102 as image 204 .

Consider now the situation where the position of the bonding tool 104 is shifted by the distance 222, for example due to a change in temperature in the system. As shown in FIG. 2A , the offset image of bonding tool 104 is shown as position 206 and is imaged along the path of second position trace 214 . As shown in FIG. 2A , direct image beam 214 travels along a similar path as direct image beam 210 from first location 202 . Through the first lens element 108 , the image of the second location 206 is propagated as a direct image beam 214 . Direct image beam 214 then passes through top surface 226 of rectangular prism 106 to first internal reflective surface 218 . The direct image beam 214 is then reflected to a second inner reflective surface 220 which in turn directs the beam to a third inner reflective surface 221 (best shown in Figure 3). Next, direct image beam 214 propagates through top surface 226 of rectangular prism 106, forms reflected image beam 216, and passes through second lens element 110 to image plane 112B. Reflected image beam 216 is observed by imaging unit 102 as a reflected image formed at second location 208 . Although the above example is described based on a change in position along the X axis, it is equally applicable to a change along the Y axis.

As shown, the initial displacement of the bonding tool 104 (shown as the offset position 222 ) is represented by the positional difference 224 of the second position 208 of the measured position of the bonding tool 104 relative to the reference position 204 . As shown in the diagram above, displacement in assembly 109 does not affect the reflected image observed by imaging unit 102 . In other words, the assembly 109 of the present invention can translate along one or both of the X and Y axes such that the image of the bonding tool 104 appears relatively stationary to the imaging unit 102 . However, there is minimal error in the measured position of bonding tool 104 due to distortion in the lens system (discussed in detail below).

Referring again to FIG. 2A , the apex 228 (shown as a dashed line) of the rectangular prism offset alignment tool 109 is located approximately midway between the first optical axis 114 and the second optical axis 226 . To facilitate mounting of the rectangular prism 106 , the lower portion 235 of the rectangular prism 106 may be eliminated, providing a bottom surface 223 substantially parallel to the top surface 226 . Removal of lower portion 235 does not affect the reflection of image rays, since image rays emanating from object plane 112A do not hit bottom surface 223 .

The exemplary rectangular prism 106 includes a top surface 226 , a first reflective surface 218 , a bottom surface 223 , a second reflective surface 220 , and a third reflective surface 221 . If the top surface 226 is arranged such that the optical axes 114, 116 are perpendicular to the top surface 226, then the first reflective surface 218 will have a first angle 230 of about 45° with respect to the top surface 226 and a first angle 230 of about 135° with respect to the bottom surface 223. The second angle 234°. Likewise, ridgeline 225 (formed by the intersection of second and third reflective surfaces 220 and 221 ) has similar angles 232 and 236 relative to top surface 226 and bottom surface 223 , respectively. Furthermore, the second and third reflective surfaces 220 and 221 are orthogonal to each other along the water dividing line 225 . In this exemplary embodiment, the bottom surface 223 of the rectangular prism 106 can be used as a mounting surface, if desired. It should be noted, however, that the top surface 226 does not necessarily need to be formed such that image rays and reflected rays are perpendicular thereto. In this way, the rectangular prism 106 will redirect the incident light or transmit the image of the bonding tool 104 parallel to itself, causing the incident and reflected beams to have an offset equal to 118 .

The present invention may employ, for example, light in the visible, UV, and IR spectrum, preferably at wavelengths that exhibit total internal reflection relative to the material from which rectangular prism 106 is made. The material from which the rectangular prism offset alignment tool 106 is made is selected on the basis of the desired wavelength of light through which the tool will pass. It is anticipated that the fabrication of the rectangular prism offset alignment tool 109 may be used to process light in a predetermined range of wavelengths between the UV (1 nm) to near IR (3000 nm). In a preferred embodiment, the light may be selected to have a wavelength range between approximately i) 1 to 400 nm, ii) 630 to 690 nm, and iii) 750 to 3000 nm. Illumination may also be provided by ambient light or by using artificial light sources (not shown). In an exemplary embodiment, rectangular prism 106 may be fabricated using optical glass typically having a refractive index of 1.5 to 1.7. Note that this index of refraction is based on the material chosen to have maximum transmission at the desired operating wavelength. In one embodiment, the rectangular prism offset alignment tool 109 has a refractive index of approximately 1.517.

3 is a perspective view of image traces traveling in a direction perpendicular to the pitch of lens elements 108, 110 according to an exemplary embodiment of the invention. The imaging properties shown in FIG. 2A are also evident in FIG. 3 . For example, the reference position of the bonding tool 104 is represented by the first position 302, and its image 304 is regarded as a first direct image ray 310, which travels along the first optical axis 114, passes through the first lens element 108; the top surface 226 of the prism 106; collide with the first reflective surface 218 of the rectangular prism 106; propagate through the rectangular prism 106 on a path parallel to the top surface 226; collide with the second reflective surface 220; collide with the third reflective surface 221, Exits from rectangular prism 106 through top surface 226 and propagates through second lens element 110 along second optical axis 116 to image plane 112B, constitutes light trail 312, and is observed by imaging unit 102 at location 304. FIG. 3 also shows the displacement of the bonding tool 104 as shown by the path of the light traces 314 , 316 from the second position 306 to the second observation position 308 .

4A-4B are perspective and side views, respectively, showing lens elements 108, 110 and rectangular prism 106 in an exemplary embodiment of the invention. The two lens elements 108 , 110 (or 205 ) are preferably doublets positioned above the rectangular prism 106 according to their focal distance from the object plane 112A and image plane 112B and the imaginary plane 211 . Lenses pairs are preferred based on their excellent optical properties. As shown in FIGS. 4A-4B , rectangular prism 106 in one exemplary embodiment has three internally reflective surfaces 218 , 220 and 221 . As shown in FIG. 4B, the outer edges of the lens elements 108, 110 and the rectangular prism 106 coincide with each other.

Figure 5 illustrates telecentricity in an exemplary embodiment of the imaging system of the present invention. As shown in FIG. 5, the lens elements 108, 110 produce a single magnification and are positioned relative to the rectangular prism 106 such that the telecentricity of the machine vision system can be maintained. Note that front focal distance 502 from lens element 108 to apex 228 of rectangular prism 106 is equal to front focal distance 502 from lens element 110 to apex 228 of rectangular prism 106 . Note also that the back focus distance 504 from lens element 108 to object plane 112A is equal to the back focus distance 504 from lens element 110 to image plane 112B.

FIG. 6 is a detailed view of an exemplary rectangular prism 106 in accordance with the present invention. It should be noted that the inner reflective surface 218 and the water cut line 225 allow the image of the bonding tool 104 to be shifted in the X and Y directions. It should also be noted that the surfaces of the rectangular prism 106 are preferably ground so that the reflected beam is parallel to the incident beam within 5 arc seconds.

As shown in FIG. 6 , surfaces 220 and 221 are orthogonal to each other along water-cutting line 225 . In addition, the angle between watershed line 225 and surface 218 is approximately 90°. Also, the surface 218 and the watershed form an angle of 45° with respect to the top surface 226 and the bottom surface 223 . It should also be noted that the surfaces 218, 220 and 221 intersect to form a triangular bottom surface 223, which can be used to conveniently mount the rectangular prism 106.

7A-7C illustrate the results of tilting about the orthogonal axis of the rectangular prism offset alignment tool 109 in an exemplary imaging system. FIG. 7A is a top view of lens elements 108 , 110 and rectangular prism 106 . Exemplary image origins 702, 703, 704, 706, 707, and 708 correspond to the locations of imaging traces 210, 214 (shown in FIG. 2A). Note that optical axis position 710 corresponds to where the image of bonding tool 104 would be if rectangular prism 106 were not tilted along the Z-axis.

7B-7C are graphs of the results obtained for tilting about the Z-axis, showing tilt in arc minutes versus error in microns. Figure 7B shows the results of tilt about the Z axis versus error and image position along the Y axis, and Figure 7C shows the results of tilt about the Z axis versus error and image position along the X axis.

8A-8C illustrate the results of tilting about the X and Y axes of the exemplary imaging system. FIG. 8A is a side view of additional exemplary image traces 210 , 212 , 214 , 216 . In FIG. 8A, the X and Y axes are indicated by arrows 804 and dots 802, respectively, and arrow 806 indicates tilt.

8B-8C are graphs of the results obtained for tilting about the X and Y axes, showing tilt in arc minutes versus error in microns. Figure 8B shows a plot of tilt about the X axis versus error and image position along the Y axis, and Figure 8C shows a plot of tilt about the Y axis versus error and image position along the X axis.

Fig. 9 is a detailed side view of an image trace according to a third exemplary embodiment of the present invention. In FIG. 9 , the reference position of the bonding tool 104 is shown as a reflected ray from a first position 914 (on the object plane 112A forming part of the plane 112 shown) along the first optical axis 114 (shown in FIG. 1 ). ) propagates, constituting direct image beam 922 from first location 914 through lens element 902 . Note that in this exemplary embodiment, lens element 902 has a relatively flat upper surface 904 and a convex lower surface 906 . The direct image beam 922 travels along the first optical axis 114 , then passes through the upper surface 904 of the lens element 902 , before passing through the raised lower surface 906 . The direct image beam 922 is then reflected onto the fully reflective surface 908 . In a preferred embodiment, the fully reflective surface 908 is a flat mirror. Next, direct image beam 922 passes back through lens element 902 along second optical axis 116 (shown in FIG. 1 ), constituting reflected image beam 920, and onto image plane 112B. Imaging unit 102 (shown in FIG. 1 ) detects image 912 of reflected image beam 920 . Similarly, the displacement of the bonding tool 104 is also shown in FIG. 9 and is shown by the path of the direct image beams 918 , 924 from the second position 910 to the second viewing position 916 .

Due to the nature of conventional wire bonding machines, the capillary tool tends to move in an arcuate fashion (arc 1414 illustrated in FIG. 14A ) as it is moved from an idle position to a bonded position. Thus, when capillary tip 1400 is brought into engagement with a device (not shown), its movement along arc 1414 introduces X and Y positional errors. The height at which the capillary tip 1400 contacts the device varies from system to system, and also from device to device that is engaged. These X and Y position errors and variations in the angle of the optical axis result in splice position errors.

FIG. 14A illustrates an X and Y plot of the tip 1400 of a capillary 1404 as it moves along an arc 1414 along the Z axis as it moves to the position of the engagement device (not shown) in accordance with the present invention. location device. This exemplary system measures and corrects for errors introduced by X and Y deviations of different positions of the capillary tip 1400 along the Z axis. Ideally, this embodiment includes optical system imager 1402 , lenses 110 and 108 (or a single lens, such as shown in FIG. 2B ), illuminator 1020 such as a ring illuminator, and rectangular prism 106 .

In an exemplary embodiment, optical system 1402 includes low and high magnification optical elements. As shown in FIG. 14A , the lens 110 is disposed between the optical system 1402 and the rectangular prism 106 along the first optical axis 1401 . The lens 108 is disposed between the object plane 1412 and the rectangular prism 106 along the second optical axis 1403 and is on the same horizontal axis as the lens 110 . The first and second optical axes are substantially parallel to each other, if not absolutely parallel.

Using illumination system 1020 (eg, ring illuminator), lenses 108 and 110 , and rectangular prism 106 , an image of capillary tip 1400 is formed on image plane 1410 of optical system 1402 . The images of the capillary tip 1400 at each nominal Z height can be acquired and processed by the imaging system 1402 to determine the X and Y positions of the capillary tool tip 1400 as it moves along the arc 1414 . When the capillary tip 1400 is in contact with different devices at different Z heights while moving along the arc 1414 (as shown in FIG. 14B ), the error in engagement position due to its deviation in X and Y position can be determined by, for example, a suitable X-Y table. (not shown) to correct for repositioning, thus improving the accuracy of lead boundaries when bonding very fine pitch devices. With this exemplary system, as shown in FIG. 14B , an image of capillary tip 1400 can be tracked as it moves along arc 1414 from start point 1520 to end point 1522 .

15A-15B illustrate another exemplary embodiment of the present invention. Since the deviation of the angle of the optical axis is another error-generating factor, the present inventors proposed a method to measure and ultimately resolve this error. As shown in FIG. 15A , a first position indicator 1501 such as a reticle is placed on the image plane 1410 (relative to the optical system 1402 , the image plane 1410 can be regarded as the object plane 1410 ) as required. A second position indicator 1503 is placed above the object plane 1412 and is imaged on the image plane 1410 by the rectangular prism 106 and the lenses 108 and 110, thus by placing the two crosshairs 1502, 1504 (set respectively at the reticle plates 1501, 1503) to determine the angular deviation of the optical axis.

FIG. 15B illustrates displacement error between positions 1512 and 1514 of position indicators 1501 and 1503 as observed by optical system 1402 .

Thus, by determining the deviation in the position of the two crosshairs on reticle 1501 and 1503, the error introduced by the angular variation of optical system 1402 can be measured and then compensated for. The error is measured by first determining the position of the first crosshair on the reticle 1501 at the image plane 1410 (the image plane 1410 can be regarded as the object plane relative to the optical system 1402). Next, the location of the second crosshair at the object plane 1412 of the rectangular prism 106 is determined. Finally, a displacement error is calculated by measuring the difference between the first and second positions. From this data it is possible to correct for joint position errors, which are X(ΔX) and/or Y due to changes in the angle of the optical system and/or differences in the position of the capillary tip 1400 when the capillary tip 1400 touches different devices at different heights. (ΔY) caused by position deviation.

Referring to Figure 10A, a side view of yet another exemplary embodiment of the present invention is illustrated. In FIG. 10A, an imaging system 1000 includes a plurality of rectangular prisms 1014, 1020, 1026 and respective lens groups 1016/1018, 1022/1024, 1028/1030, which are used as an alignment device to improve die fixation and assembly stability. Accuracy of pick/place, eg dies 1008, 1010, 1012. This would effectively replace the conventional up-looking camera (ie die camera - not shown) that is commonly found in most conventional medium to high precision placement (e.g. die cameras). fixation and pick/place) equipment. In the exemplary embodiment, groups of a plurality of rectangular prisms 1014 , 1020 , 1026 each with a different lens pitch 1017 , 1023 , 1029 each provide an indirect image of the position of the die 1018 , 1010 , 1012 . Those of ordinary skill in the art understand that only one die is viewed at a time. Using a combination of multiple rectangular prisms/lenses enables the use of dies of various sizes. In other respects, such as materials used, reflection method, etc., this exemplary embodiment is similar to the first exemplary embodiment.

As noted above, this variation of the first exemplary embodiment accommodates the various die sizes that these types of equipment accept and place. In this exemplary embodiment, a downward facing optical probe 1002 , such as a camera (eg, a substrate camera), observes features on the underside of a component such as die 1008 , 1010 or 1012 to be placed. These features of the die 1008, 1010, 1012 can then be identified by an imaging system (not shown) so that the die can be accurately positioned using the pick tool 1004 based in part on a predetermined distance between the pick/place tool 1004 and the optical detector 1002. placed on a substrate (not shown). Those of ordinary skill in the art understand that the pick tool 1004 can be a rotating or non-rotating picking tool. This exemplary embodiment also retains the optical advantages in terms of accuracy of alignment of the rectangular prisms described above in the first exemplary embodiment.

Figure 10B is a plan view of the exemplary embodiment shown in Figure 10A. In FIG. 10B , rectangular prisms 1014 , 1020 , 1026 are placed adjacent to each other forming assembly 1015 . If desired, the rectangular prisms 1014, 1020, 1026 may be bonded together using conventional adhesive methods, or they may be held in alignment with each other using mechanical devices such as clamps or, for example, container assemblies. The latter approach allows simple replacement of individual rectangular prism/lens assemblies to accommodate different sized dies as required. Although this exemplary embodiment shows three corner prism shifting tools, it should be understood that at least two corner prism shifting tools could be used.

If desired, lenses 1016, 1018, 1022, 1024, 1028, 1030 may be formed from a single optical element rather than multiple individual lenses to simplify assembly of the system. This approach is illustrated in Figures 10C-10D. As shown in FIG. 1OC, lens sheet 1040 is embedded within optical elements 1016a, 1018a, 1022a, 1024a, 1028a, 1030a substantially equivalent to respective lenses 1016, 1018, 1022, 1024, 1028, 1030.

12A-12F illustrate another embodiment of the present invention. In these exemplary embodiments, right angle prisms are used to improve alignment accuracy of the optical fibers. As in the previous exemplary embodiments, the use of rectangular prisms allows the use of a single optical detector rather than conventional multiple detector systems.

12A, this exemplary embodiment includes a rectangular prism 1014, lenses 1016, 1018, fiber cladding edges 1210, 1211 to cores 1212, 1213 respectively (which in turn generate reflections 1224, 1225 to reveal cladding edges 1210, 1211) dark field illumination system 1220, 1221 (well known to those skilled in the art) for illumination. In this exemplary embodiment, downward facing optical fiber 1208 is viewed by downward facing optical detector 1002, such as a camera (ie, substrate camera). The downward facing optical detector 1002 detects the emitted light 1222 from the fiber core 1212 and can then determine a suitable offset 1027 between the fiber centerline 1223 and the centerline of the downward facing optical detector 1002 . As further shown in FIG. 12A, the downwardly facing optical fiber 1208 and the optical detector 1002 are offset from each other by a predetermined distance 1006. Also shown is the case of an upward facing optical fiber 1209 and associated dark field illumination system 1221 disposed adjacent to the rectangular prism 1014 .

FIG. 12B is a plan view of the exemplary embodiment shown in FIG. 12A showing the relative positions of lens groups 1016 / 1018 and rectangular prism 1014 .

Then, in FIG. 12C , the downward facing optical probe 1002 and downward facing optical fiber 1208 are repositioned such that the centerline 1229 of the downward facing optical probe 1002 is aligned with the centerline 1231 of the upward facing optical fiber 1209 . Again dark field illumination system 1221 is used to illuminate upward facing fiber 1209 for identification by the imaging system to ensure proper alignment with optical detector 1002 .

Next, as shown in Figure 12D, the optical detector 1002 and downwardly facing optical fiber 1208 are again repositioned according to the offset 1027 determined in the process discussed above with respect to Figure 12A. As a result, the downward facing optical fiber 1208 and the upward facing optical fiber 1209 are aligned with each other.

Fibers 1208 and 1209 are then joined at junction 1226 using conventional techniques, such as using radiation (not shown) to fuse the fibers together, or mechanical means, for example, as shown in FIG. 12E.

Figure 12F illustrates yet another embodiment of the present invention. In this exemplary embodiment, a rectangular prism offset alignment tool 1014 is used to align the individual fibers (sub-fibers) 1202a of the fiber splitter 1200 with respect to the individual fibers 1208 and so on. As in the previous exemplary embodiments, the use of a rectangular prism offset alignment tool allows the use of a single optical detector without the need for conventional multi-detector systems. Since the steps of aligning and coupling the optical fiber 1208 and the sub-fibers 1202a, b, etc. are similar to the above exemplary embodiment, it will not be repeated here.

Once the first fiber optic is aligned with the single fiber 1208, the process is repeated for another fiber optic, such as 1202b, and additional single fibers (not shown).

Of course, this exemplary embodiment is not limited to the fiber bundles of the fiber splitter located below the optical detector 1002 . This embodiment can also reverse the relative positions of fiber bundle 1200 and fiber 1208 such that fiber bundle 1200 is positioned above rectangular prism 1014 .

13A-13D illustrate another embodiment of the present invention. In this exemplary embodiment, a rectangular prism offset alignment tool is used to improve alignment accuracy of the optical fiber 1208 with circuit components such as the detector 1302 . In FIG. 13A, exemplary detectors 1302 are part of array 1300, although the invention is not so limited. It is also contemplated that detector 1302 may be a diode such as a photodiode or an optical radiation emitter. As in the previous exemplary embodiments, the use of a rectangular prism offset alignment tool allows the use of a single optical detector without the need for conventional multiple detection systems.

Referring to FIG. 13A, this exemplary embodiment includes a rectangular prism 1014, lenses 1016, 1018, dark field illumination for illuminating the fiber cladding edge 1210 of the fiber core 1212 (which creates reflections 1224 to outline the cladding edge 1210) System 1220 (well known to those skilled in the art), and optical detector 1002. In this exemplary embodiment, downward facing optical fiber 1208 is viewed by downward facing optical detector 1002, such as a camera (eg, a substrate camera). Downward facing optical detector 1002 detects light 1222 emitted from fiber core 1212 and can then determine a suitable offset 1027 between fiber centerline 1223 and centerline 1229 of downward facing optical detector 1002 . As further shown in FIG. 13A, the downward facing optical fiber 1208 and the optical detector 1002 are offset from each other by a predetermined distance 1006.

In FIG. 13B , down-facing optical probe 1002 and down-facing optical fiber 1208 are then repositioned such that centerline 1229 of down-facing optical probe 1002 is aligned with optical centerline 1304 of probe 1302 . It will be appreciated that the optical centerline 1304 may not necessarily coincide with the physical center of the detector, but rather depends on the particular layout of the detector 1302 . Here, determining the optical centerline 1304 may be accomplished by determining the location of the center of the detector's activation-sensitive region.

Next, as shown in FIG. 13C , the optical detector 1002 and downwardly facing fiber 1208 are repositioned again according to the offset 1027 determined in the process discussed above with reference to FIG. 13A (offset 1027 is shown in FIG. 13A ). As a result, downward facing fiber 1208 and detector 1302 are aligned with each other. As shown in Figure 13D, the optical fiber 1208 and detector 1302 are then held in alignment using conventional techniques such as optical epoxies, UV epoxies.

Although the present invention has been primarily illustrated and described by use of a rectangular prism device, such as a rectangular prism, the present invention is not limited thereto. Other prism devices may be used, in particular other reflective prisms. In some arrangements of the invention it is desirable to have parallel image rays. In such setups, reflective prisms such as right angle prisms may provide beams entering and exiting substantially parallel to each other; however, in some setups non-parallel beams/image rays may be desired, so other types of prisms may be utilized.

Although the invention has been described with reference to these exemplary embodiments, it is not limited thereto. Rather, the appended claims should be construed to include other variations and embodiments of the invention which can be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims (18)

1 and wire bonder and optical image former make the system that is used for determining the wire bonding tool position together, this system comprises:

Be located at the prism under this optical image former and this wire bonding tool; With

Along primary optic axis at least one lens between the bottom of this prism and this wire bonding tool, these at least one lens and this prism define an object plane between this bottom of these at least one lens and this wire bonding tool, and between this prism and this optical image former, these at least one lens and this prism define a picture plane between these at least one lens and this optical image former along these at least one lens of second optical axis.

2, system as claimed in claim 1, wherein this prism is a right-angle prism.

3, system as claimed in claim 1, wherein these at least one lens comprise first lens and second lens, along primary optic axis first lens between this bottom of this prism and this wire bonding tool, first lens and this prism limit this object plane, between this prism and this optical image former, second lens and this prism limit this as the plane along second optical axis, second lens.

4, system as claimed in claim 1, wherein the primary optic axis and second optical axis are parallel to each other basically.

5, system as claimed in claim 1 also comprises:

Be located in the primary optic axis and the primary importance benchmark of this object plane top; With

Be located in second optical axis and this second place benchmark as the top, plane.

6, system as claimed in claim 5, wherein primary importance benchmark and second place benchmark are respectively graticles, it is last that the picture of first graticle is superimposed upon the picture of second graticle, and offer this optical image former.

7, system as claimed in claim 6 also comprises the processor of communicating by letter with this optical image former, is used for determining in the difference of the difference of the X-axis between first and second graticles or Y-axis at least one.

8, system as claimed in claim 1 also comprises the luminaire between this bottom that is located at this object plane and this wire bonding tool.

9, system as claimed in claim 1, wherein, when this wire bonding tool was mobile along the axle of a perpendicular, the indirect image of its most advanced and sophisticated position at least of this wire bonding tool offered this optical image former through these at least one lens with this prism.

10, system as claimed in claim 1, wherein these at least one lens provide a plurality of magnification ratio ranks of image.

11, system as claimed in claim 1, wherein this optical image former is camera or Position-Sensitive Detector.

12, one of at least method in mapping X-axis of capillary tool tip and the Y-axis position, this method comprises:

In optical image former, receive first image of the capillary tool tip that is positioned at a Z shaft position;

In optical image former, receive second image of the capillary tool tip that is positioned at the 2nd Z shaft position;

Utilize first image that is received and second image that is received, determine that this capillary tool tip is from (1) X-axis alternate position spike of a Z shaft position to the two Z shaft positions or at least one (2) Y-axis alternate position spike.

13, as the method for claim 12, wherein said determining step comprises determines X-axis alternate position spike and Y-axis alternate position spike.

14, as the method for claim 12, wherein the step of (1) reception first image is included in first image that the indirect image of conduct that provides via the right-angle prism offset tool is provided in the optical image former, and the step that (2) receive second image is included in second image that another the indirect image of conduct that provides via this right-angle prism offset tool is provided in this optical image former.

15,, also comprise in X-axis alternate position spike and the Y-axis alternate position spike at least one proofreaied and correct as the method for claim 12.

16, be used to measure the method that changes the error of introducing when using the wire-bonded machine owing to the angle of the optical system with prism, this method comprises:

Determine to be located at the first cross-hair position on first graticle of object plane of this optical system;

Determine to be located at the second cross-hair position on picture second graticle on plane of this optical system; And

Determine the deviation between the first cross-hair position and the second cross-hair position, to measure this error.

17, adopt optical image former to determine the method for the site error of wire bonding tool when it is mobile along the Z axle, this method comprises:

In this optical image former, receive first image of at least a portion of this wire bonding tool that is positioned at a Z shaft position place;

First image is offered processor;

In this optical image former, receive second image of at least a portion of this wire bonding tool that is positioned at the 2nd Z shaft position place;

Second image is offered processor;

Determine the site error between first and second positions.

18, as the method for claim 17, wherein the step of (1) reception first image comprises via a right-angle prism offset tool reception as first image of image and the step that (2) receive second image comprise via second image of this right-angle prism offset tool reception as another indirect image indirectly.

Images