JPH09223707A - Multi-tool wire bonder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently process fine-pitch directional capillaries in two directions, without using a separate machine or twice passing through the same machine. SOLUTION: A multi-tool ball bonder comprises a first and second tools 150 and 152 mounted on a single head 182 and needs a visual unit 178, positioner 168 and compute 228 only. The ball bonder can interconnect between a semiconductor device 148 and lead frame fingers 148 in a first direction, using the head 182 and second tool 152 can interconnect in a second direction, without adding any apparatus or process.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to interconnections on semiconductor devices, and more particularly to multiple tool wire bonders.

[0002]

BACKGROUND OF THE INVENTION In semiconductor manufacturing, ball bonding is a widely used method for connecting an internal semiconductor die to external leads. Wires or dies are bonded with a pad pitch less than 90 μm using an oriented fine pitch capillary. These capillaries are joined at a limited angle. Join first
To orient in the (eg vertical) direction and the second (eg horizontal) direction, the semiconductor chip must be passed through two separate machines or the same machine with the capillaries turned twice. Another method is 2 such as ABACUS III made by Texas Instruments Incorporated of Dallas, Texas.
Using a head wire bonder. These methods increase the work, and the more work increases the chances of making an error.

[0003]

Therefore, there is a need for a ball bonder capable of efficiently processing a capillary having a fine pitch and directionality in two directions without using another machine or passing through the same machine twice. Is. One aspect of the present invention provides a wire bonder that eliminates or substantially reduces the drawbacks of previously developed ball bonders and bonding methods. In one aspect of the present invention, a ball bonder including a computer, a visual device, a positioning device, and a bonding head having a first bonding tool that bonds in a first direction and a second bonding tool that bonds in a second direction. provide. In another aspect of the invention, a Z driver is coupled to a wire bonding head that includes at least first and second tools to selectively contact the first tool or the second tool with the semiconductor chip.

A technical advantage of the present invention is that the first direction and second direction interconnections of semiconductor devices and leadframe fingers can be accomplished without the need for additional equipment. Another technical advantage of the present invention is that the interconnection of the semiconductor device and the leadframe fingers in the first direction and the second direction can be performed without additional steps.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION

The preferred embodiment of the present invention and its advantages are as follows.
It can best be understood by referring to FIGS. The same numbers are used for the same or corresponding parts in each figure.

In FIGS. 1-3, an internal semiconductor die or chip 10 connects to an external lead or finger 12 of a lead frame. Ball bonding is widely used for such connection. Generally, the step of connecting is to bond a thin wire 14, typically 25-30 μm in diameter, typically gold or aluminum, to the lead fingers 12 and bonding pads 16, 18 as shown in FIG.

With the present invention, ball bonding of fine pitch capillaries is particularly facilitated. This is an extension of the ball bonding method and is used for bonding when the pad pitch is generally smaller than 90 μm. In basic ball bonding, a ball is made at one end of the wire 14 and a crimping arm (for example, 200 in FIG. 5) is used.
Is bonded to the first bonding pad (for example, the bonding pad 16) by. The crimping arm comprises a capillary tube 22 and the wire 14 is slid into a capillary 24 of the capillary tube 22. In general, electronic flame off (EFO) 2
8 (FIG. 2) is used to form a ball or free air ball 26 at the end of the wire 14. The ball 26 is placed in the center of the inner circular groove 30 of the capillary tube 22. Next, the ball 26 is lowered onto the bonding pads 16 and 18 and pressed onto the dies 16 and 18 as shown in FIG.
The ball 26 can be used to bond the wire 14 to the die pad or bond 16, 18 because the two materials undergo plastic deformation and interfacial slip due to the application of load, temperature and ultrasonic energy. is there. The crimp arm and capillary tube 22 form a weldment or bond by not only applying pressure directly, but also applying additional energy by ultrasonic waves, heat or other means.

The first bond is bonded to the bonding pads 16 and 1.
8 is formed, the crimp arm moves the capillary tube 22 to the bonding pad of the leadframe finger 12 and feeds the wire 14 through the capillary tube 22 to form a wire loop 34 (FIG. 1).
Bonding part 12 through capillary tube 22
Pressure and energy are applied again to form a bond between the wire 14 and the bond pad 12 of the leadframe finger. Next, the capillary tube 22 is pulled out from the bonding pad 12 by the pressure bonding arm. When the capillary tube 22 is withdrawn from the bonding pad 12, the wire 14 extending through the capillary tube 22 is held or clamped by the clamp 36 (FIG. 2). As a result, a part of the wire 14 extending from the bonding pad 12 through the capillary tube 22 is separated from the bonding pad 12. This leaves only the wire loop 34 extending from the bonding pads 16 and 18 of the integrated circuit or chip 10 to the bonding pads 12 of the leadframe fingers.
Next, another ball 26 is made at the end of the wire 14 from the capillary tube 22 and the same process is repeated. As reference material, US Pat. No. 3,641,660, “Ball Bonding Method Using Automatic Semiconductor Bonding Machine (Th
e Method of Ball Bonding With An Automatic Semicond
uctor Bonding Machine) ", transferred to Texas Instruments. Insert this here for all purposes.

In order to increase the density of the bonding pads on the semiconductor chip 10, the connections should be as close as possible. Therefore, a fine pitch capillary with a specific orientation is used. For example, in FIG. 1, the wire loops 34 connected to the bonding pads 16 are aligned in a first direction 38 for a first orientation (eg, vertical), and similarly, the bonding pads 18 are aligned in a second direction 40 for a second orientation. (For example horizontal). To make such a connection, a right-angled or other shaped capillary tube that can be tightly joined in one direction is used. To position the loop 34 in the first direction 38 and the second direction 40 on the tip 10, either re-direct the capillary tube to pass the tip through the machine twice or two separate machines, or two. It is necessary to thread one device, a machine with two complete heads.

Next, FIG. 4 shows a schematic view of the ball bonder 44 of one embodiment of the present invention. The ball bonder 44 comprises or operates in conjunction with a material carrier 46 to provide a first
Bonding tool 50 and second bonding tool 52
The semiconductor chip on the lead frame 48 is carried to the position to be processed by. The bonding tools 50 and 52 of the single head ball bonder 44 are respectively a crimp arm,
It includes an EFO and a clamp or latch that handles the bond on the chip and leadframe 48.

The first bonding tool 50 processes bonds in a first direction, eg direction 38 in FIG. 1, and the second bonding tool 52 processes bonds in a second direction, eg direction 40 in FIG. Another bonding tool,
For example, a third bonding tool 54 shown by a dotted line in FIG.
May be added. The third bonding tool 54 also makes a bond in a third orientation or configuration.

Bonding tools 50 and 52 are connected to a computer 56 by cables 58 and 60, respectively.
Connect to Computer 56 may be any digital computer suitable for controlling a machine. Tools 50 and 52 are attached to a Z-direction positioner 62 that connects to computer 56 with cable 64. The Z-direction positioning device 62 is attached to the positioning device 6 by a mounting link 66.
Attach, ie, fix to 8. Positioning device 68
May be an XY table (X table 70, Y table 72). The positioning device 68 connects to the computer 56 with a cable 74. The positioning device 68 may be attached to the body 76. A vision device 78 is used to optically detect the presence of the chip and leadframe 48 on the material carrier 46. The vision device 78 comprises a camera and optics and connects to the computer 56 by a cable 80. In this way, the ball bonder 44 has one bonding head 82.
And the bonding head 82 includes, for example, the tool 50.
And 52, a visual device 78, and a positioning device 68.

To explain the operation of the ball bonder 44, the material carrying device 46 is a semiconductor chip and lead frame 4.
8 is placed in the field of view 84 of the visual device 78. Computer 5
6 electronically senses the exact position of the semiconductor chip and the lead frame 48 and uses the positioning device 68 to accurately position the first tool 50 so that a bond can be made in the first direction. Next, the Z-direction positioning device 62 uses the first tool 5
Clear 0 to make a bond in response to the signal sent from computer 56 over cable 64. The tool 50 is moved by the positioning device 68 in the required increments to make the next bond in the same first direction. Upon completing the desired number of bonds in the first direction, the Z-positioning device 62 receives instructions from the computer 56 sent by the cable 64 and the first tool 50.
To the play position and the second tool 52 to the active position. The same process is repeated using the tool 52 to make a bond in the second direction. When the processing of the specific semiconductor chip and the lead frame 48 is completed, the material conveying device 46
Moves to the next chip and lead frame 48.

The ball bonder 44 requires only one visual device 78, one positioning device 68, and one computer 56. Further, with a multiplexer, the number of signals issued by computer 56 to control tools 50 and 52 should be minimized.

Next, FIG. 5 shows a ball bonder 144. The ball bonder 144 includes a single head 182 having a first bonding tool 150 and a second bonding tool 152.
Is provided. The bonding tool 150 includes a crimp arm 200 having a capillary tube 202 in the first direction,
It is provided with an EFO 204 and a clamp 206. The fine wire is threaded through the clamp 206 into the capillary 202 of the compression arm 200. Similarly, the second tool 152 includes a compression arm 210, a capillary tube 212 and an EFO2.
14 and a clamp 216.

The first tool 150 includes a plurality of cables 22.
0 connects to the multiplexer 222. Similarly the second
Tool 152 connects to multiplexer 222 by a plurality of cables 224. The multiplexer 222 connects to the computer 228 by a plurality of cables 226. The computer 228 includes ultrasonic drive, positioning feedback processing, wire clamp drive, touchdown detection, instructions to activate the ball bonder 144 and error detection.

The ball bonder 144 includes a visual device 178. The visual device 178 includes a camera and an optical device that electronically detect the positions of the semiconductor chip and the lead frame 148. The material carrier 146 positions the chip and lead frame 148 at the correct processing location on the ball bonder 144. Further, the positioning device 168 positions the tools 150 and 152. The positioning device 168 is, for example, the X table 170 and the Y table 172.

The ball bonder 144 has a Z-direction positioning device 162. The Z-positioning device 162 is shown in this embodiment as a rod 161 and is rotated to rotate the tool 1
The 50 or tool 152 is brought into contact with the chip and lead frame 148. Or fix the rod 161
The tools 150 and 152 may have their own motors or other means to move the tools relative to the rod 161. This will be described in detail below. Tool 15
0 and 152 have a play position and an active position, respectively. In the play position, the tool is in a safe position away from rod 161. At the same time, the other tool engages the rod 161. In this embodiment, tools 150 and 152
Processes the chip and the lead frame 148 in order.
In this embodiment, the default position for tools 150 and 152 is the play position. The Z direction positioning device 162 is
A solenoid driven clutch is used to activate tools 150 and 152.

Referring now to FIG. 6, the Z-direction positioner or Z-driver 262 comprises a rod shaft 261. The shaft 261 includes a first support 264 and a second support 266. Supports 264 and 264 are bearings 2
68 is used to rotatably support the shaft 261. The support 266 includes a motor 270, and the motor 270
Includes a motor coil 272 and a motor magnet 274. The motor 270 is a computer such as a computer 228.
Connect to and receive the instructions needed for the bonding cycle.

A shaft 261 extends through a portion of the first tool 250. The tool 250 includes a bearing 276 between the tool 250 and the shaft 261, and rotatably supports the bearing 276. The first clutch element 278 is attached to the shaft 261 and the second clutch element 280 is attached to the tool 250. If it is desired to move the tool 250 with the shaft 261, the second clutch element 280 is brought into contact with the first clutch element 278 by any means known in the art, such as a solenoid 282. When the first clutch element 278 and the second clutch element 280 are not in contact, the tool 250 is moved to the safe position by the biasing means or counterweight. Similarly, tool 252
Is rotatably supported on the shaft 261 by the bearing 290. The third clutch element 292 is attached to the shaft 261 and the fourth clutch element 294 is attached to the second tool 252. Third clutch element 292 and fourth
Tool 2 if clutch element 294 is not engaged
52 is moved to a safe or idle position by a biasing means or spring. Tool 252 to shaft 26
If desired to move with 1, contact the fourth clutch element 294 with the third clutch element 292 using any means known in the art such as solenoid 296.

Referring now to FIG. 7, another Z-axis positioner or driver 362 for use with the ball bonder 144 is shown. The driver 362 comprises a shaft 361 rigidly supported by a first support 364 and a second support 366. The first tool 350 has a bearing 376 as shown.
Is rotatably supported on the shaft 361. A motor 370 is provided that operates between the shaft 361 and the tool 350 to move the shaft 361 and the tool 350 relative to each other. The motor 370 includes a coil 372 and a motor magnet 374 as shown.
Similarly, the second tool 352 is rotatably supported by the bearing 380, and can be selectively rotated with respect to the shaft 361 by the motor 382 including the coil 384 and the magnet 386. In the positioning device 362, the computer 37, for example the computer 228, drives the motor 37
0 or motor 382 to selectively send control signals to activate tools 350 and 352 throughout the bonding cycle.

Another Z drive design includes solenoid driven pins or magnetic couplings to lock the tool to the Z drive 162. In yet another embodiment,
The tools 150 and 152 may be mounted on a swivel and rotated into the active position, for example mounted on a common axis, spaced apart.

By using a single vision device 178, a single computing device 228, a single positioning device 168, and a ball bonder 144 with a single Z driver 162, at least two different directions are provided. An apparatus is provided that can process capillaries 202 and 212, thus completing a two-way bond with a single head bonder 144. This reduces size, cost, complexity and tool-to-tool variations.

Although the present invention and its advantages have been described in detail, various changes, substitutions and alterations can be made without departing from the spirit and scope of the present invention defined in the claims. .

With respect to the above description, the following items are further disclosed. (1) A multi-tool wire bonder for automatically forming a ball bond to interconnect a thin wire between a semiconductor chip and a bonding pad of a lead frame, the computer controlling the interconnect, A visual device for electronically detecting the position of the semiconductor chip, a positioning device, and a tool head attached to the positioning device, the first device forming a ball bond on the chip in a first direction by being coupled to the computer.
A bonding tool, coupled to the computer to form a ball bond on the chip in a second direction;
A multiple tool wire bonder with a tool head with a second bonding tool, which is near the bonding tool.

(2) The multiplexing according to claim 1, further comprising a Z driver for selectively contacting the first bonding tool with the semiconductor chip and selectively contacting the second bonding tool with the semiconductor chip. Tool wire bonder. (3) The positioning device includes an XY table,
A multi-tool wire bonder as set forth in claim 1. (4) The multi-tool wire bonder according to claim 1, wherein the tool head further comprises a third bonding tool that is coupled to the computer to form a ball bond on the semiconductor chip in a third direction.

(5) A Z driver for selectively contacting the first bonding tool with the semiconductor chip and selectively contacting the second bonding tool with the semiconductor chip is further provided, and the Z driver is rotated. A shaft rotatably supported, a first tool rotatably supported by the shaft, a second tool rotatably supported by the shaft, and the computer coupled to the shaft A motor for rotating the shaft in response to a signal from the first tool, a first clutch attached to the first tool for selectively engaging the shaft to rotate the first tool with the shaft, the second clutch
A second member attached to the tool for selectively engaging the shaft to rotate the second tool with the shaft;
The multi-tool wire bonder of claim 1, comprising a clutch.

(6) A Z driver for selectively contacting the first bonding tool with the semiconductor chip and selectively contacting the second bonding tool with the semiconductor chip is further provided, and the Z driver is a shaft. And
A shaft having a first tool rotatably mounted on said shaft and a second tool rotatably mounted on said shaft, coupled to said computer, mounted on said first tool and shaft, said computer A first motor for selectively rotating the first tool with respect to the shaft in response to a signal from the computer, coupled to the computer, attached to the second tool and the shaft, and in response to a signal from the computer The multi-tool wire bonder of claim 1, comprising a second motor that selectively rotates a second tool relative to the shaft. (7) The multi-tool wire bonder according to claim 1, further comprising a multiplexer, wherein the first tool and the second tool are coupled to the computer by the multiplexer.

(8) A single-head multi-tool wire bonder system for automatically forming a ball bond to interconnect a bonding pad on a semiconductor chip and a lead finger on a carrier, the body, the semiconductor chip. And a material carrier that holds the lead frame,
A computer controlling the system, a wire bonder head coupled to the body, coupled to the computer, in response to the semiconductor chip on the material transport device and in response to the computer, first and second directions Xy platform to activate the wire bonder on the
A visual device coupled to the body and a computer for electronically detecting the position of a semiconductor chip on the material carrier, operably coupled to the body, having a play position and an active position, on the semiconductor chip A first bonding tool, a first bonding tool, operably bonded to the body, having a play position and an active position, and forming a bond on the semiconductor chip in a second direction; A single head, multi-tool wire bonder system comprising a wire bonder head comprising a bonding tool.

(9) The wire bonder head further comprises a third bonding tool which is coupled to the computer to form a ball bond in a third direction on the semiconductor chip. Wire bonder system. (10) The single-head multi-tool wire bonder system according to claim 8, wherein the wire bonder head further comprises a Z driver for bringing the first tool and the second tool into contact with the semiconductor chip.

(11) The wire bonder head further comprises a Z driver for bringing the first tool and the second tool into contact with the semiconductor chip, and the Z driver is a rotatably supported shaft. A first tool rotatably supported by the shaft; a second tool rotatably supported by the shaft; a motor coupled to the shaft to rotate the shaft according to the computer; A first clutch attached to the first tool for selectively engaging the shaft to rotate the first tool with the shaft;
A second member attached to the tool for selectively engaging the shaft to rotate the second tool with the shaft;
The single-head, multi-tool wire bonder system of claim 8 including a clutch.

(12) The wire bonder head further includes a Z driver for selectively contacting the first tool and the second tool with the semiconductor chip, and the Z driver is
A shaft comprising a first tool rotatably mounted on the shaft and a second tool rotatably mounted on the shaft, coupled to the computer, the first tool and the shaft A first motor mounted to selectively rotate the first tool relative to the shaft in response to the computer, coupled to the computer, mounted to the second tool and shaft in response to the computer The single-head, multi-tool wire bonder system of claim 8, comprising a second motor that selectively rotates two tools relative to the shaft. (13) The single-head, multi-tool wire bonder system of claim 8, further comprising a multiplexer, wherein the first tool and the second tool are coupled to the computer by the multiplexer.

(14) A method of manufacturing a device for automatically forming a ball bond to interconnect a thin wire between a semiconductor chip and a bonding pad of a lead frame, and providing a computer for controlling the interconnect. And a tool head having a first tool for forming a bond in a first direction and a second tool for forming a bond in a second direction by electronically detecting the position of the semiconductor chip by connecting a visual device to the computer. Forming and attaching the tool head to a positioning device.

(15) The Z driver is connected to the first and second Z-drivers.
The method of claim 14, further comprising the step of coupling to a tool, selectively contacting the first bonding tool with a semiconductor chip, and selectively contacting the second bonding tool with a semiconductor chip. (16) A method according to claim 14, wherein the step of attaching the tool head to the positioning device includes the step of attaching an XY table to the tool.

(17) The step of forming the tool head may further include the step of forming a third bonding tool for connecting to the computer to form a ball bond on the semiconductor chip in a third direction. 14. The method according to item 14. 18. The method of claim 14, further comprising mounting a multiplexer between the first tool and a computer and between the second tool and a computer.

(19) The multi-tool ball bonder comprises a first tool 50, 1 attached to a single head 82, 182.
50 and second tools 52, 152. What you need is one visual device 78,178 and a positioning device 68,1
There is only one 68 and one computer device 56, 228. The ball bonders 44, 144 allow the single heads 82, 182 to interconnect in a first direction between the semiconductor devices 10, 148 and the lead frame fingers 12, 148, and the second tools 52, 152 provide equipment and process steps. The interconnection can be made in the second direction 40 without the need for adding.

[Brief description of drawings]

For a more complete understanding of the invention and its advantages, please read the description with reference to the following drawings.

FIG. 1 is a schematic view of a part of a semiconductor chip mounted on a lead frame.

FIG. 2 is a schematic sectional view of a part of a ball bonder.

3 is a schematic cross-sectional view of the ball bonder of FIG. 2, showing the formation of ball bonds.

FIG. 4 is a schematic diagram of one embodiment of the present invention.

FIG. 5 is a perspective view of an embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view of a Z driver according to one embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view of another embodiment of the Z driver according to one aspect of the present invention.

[Explanation of symbols]

 10 semiconductor device 12 lead frame finger 44 ball bonder 46 material conveying device 48 semiconductor chip and lead frame 50 first bonding tool 52 second bonding tool 56 computer 62 Z direction positioning device 68 positioning device 78 visual device 82 bonding head

Claims (2)

[Claims] 1. A multi-tool wire bonder for automatically forming a ball bond to interconnect a thin wire between a semiconductor chip and a bonding pad of a lead frame, the computer controlling the interconnect, coupled to the computer. A visual device for electronically detecting the position of the semiconductor chip, a positioning device, and a tool head attached to the positioning device, which is coupled to the computer to form a ball bond on the chip in a first direction. A multi-tool wire bonder comprising a first bonding tool, a tool head coupled to the computer to form a ball bond on the chip in a second direction, the tool head including a second bonding tool proximate the first bonding tool. . 2. A method of fabricating a device for automatically forming ball bonds to interconnect a thin wire between a semiconductor chip and a bonding pad of a lead frame, the method comprising providing a computer for controlling the interconnect. A first tool for forming a bond in a first direction and a second bond for electronically detecting a position of the semiconductor chip by connecting a visual device to the computer;
Forming a tool head with a second tool forming in a direction and attaching the tool head to a positioning device.