JPS61226936A - Wire bonding method and apparatus therefor - Google Patents

Abstract

PURPOSE:To conduct stable wire bonding at high speed by horizontally driving vertical driving and horizontal driving tables for a bonding tool according to a driving pattern similar to a reference driving pattern. CONSTITUTION:Driving control sections capable of driving parts to be driven by arbitrary driving loci are mounted to a driving motor 10 vertically moving a rocking arm 9 and an X-axis driving motor 1 and a Y-axis driving motor 2 shifting an XY table 3. The driving motors 1, 2, 10 are represented by motors M, and the travels of a bonding tool 6 moved by the motors M and the XY table 3 are proportional to the angles of rotation of the motors M. A CPU 31 obtains the renewal number (n) of an aimed position from a travel S given by a memory 32b, and encloses it into a memory 32f as an aimed renewal data (DELTASi). The moving locus of an object to be driven K draws a cycloidal curve at that time. Acceleration alpha changes in a sine wave shape, and does not vary suddenly, thus resulting in a small burden on the motors M, then also giving a small shock.

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a wire bonding method and apparatus for wiring an N-pole pad of a cliff pellet to an external terminal using a metal mist. [Problems such as technical cost of the invention] In recent years, a wire bonding device called "Digital Wire Honda" has been widely used. This wire bonding apparatus uses a solenoid as a wire clamp, and a drive tachter to move the wire clamp and bonding tool upward. These bonding ■ JA a3 The drive motor is 1 on the XY table.
The XY table is moved horizontally by a drive motor in the X direction and a drive motor in the Y direction. By moving the vertical drive element, the X-axis drive motor, and the Y-axis drive motor, the bonding wire held by the bonding tool is bonded to the semiconductor pellet and the external terminal, and electrically connected. There are the following problems with such wire bonding equipment, particularly regarding movement in the X and Y directions. In order to move the wire bonding crown in the X and Y directions, the drive motor in the X direction drives the Tanabata drive in the Y direction. For example, when moving the life bonding F and H1 from the origin O to the target position 1' (a, b) as shown in Fig. 9, the X-axis drive motor and the Y-axis drive -9 are driven as follows. Riri. Start driving these top and bottom at the same time, and check the position in the Y direction! ffi (+
When reaching Nb, stop the Y-axis drive motor. When the position in the rear X direction reaches the target value a, the X-axis drive motor is stopped. The movement trajectory of the bonding tool is shown in Figure 9! Draw J1. Since this movement trajectory ρ is curved at the position Q (b, b), the bonding tool abruptly changes its movement direction at this position Q (b, b). As a result, the bonding wire V held by the shell bends and the desired

[The loop shape is loud. To solve the above-mentioned problem, when the amount of movement in the X direction, J, and Y direction is different, the movement speed in the direction between short movements is slowed down so that the bonding tool follows the movement trajectory 92 in FIG. M゛ as if drawing. In this way, the bonding tool does not change its direction of movement midway. The time required for movement is determined by the longer of the movement m in the X direction and the movement m in the Y direction. Therefore, the time required to reach position P (a, b) in FIG. 9 and the time required to reach position R (a, c) are the same. The distance between the trajectory fJ2 and the trajectory I13 is different, so when moving to position P (a, b,) and when moving to position R (a,
The movement speed is different from that in case C). On the other hand, in order to perform reliable wire bonding, there is a limit to the allowable movement speed of the bonding tool. However, in the above-mentioned movement control, since the moving directions are different and the moving speeds are different, there is a risk that the permissible limit will be exceeded. If the movement speed of the bonding tool is constant, the three-dimensional movement trajectory of the bonding tool will also be the same, even if the movement speed is different.
As shown in FIG. 0, since the bonding wire loop shape is determined by the movement locus of the bonding tool, the bonding wire loop shape is also different. For this reason, there is a bulge that prevents stable wire bonding. Further, conventional motor drive control is shown in FIG. 11. In this drive control, as shown in FIG. 11(C), the acceleration α is set to α1 during acceleration and -α1 during deceleration, so that the acceleration is equal to 3! It is a degree of control. In this constant acceleration control, the velocity V is as shown in Fig. 11 (b
), the displacement S increases and decreases linearly as shown in
As shown in Figure <a)/,j. In the motor drive control described in -F, since the acceleration speed changes rapidly, there is a problem in that the moving bonding head receives a strong blow from the a-shaped part and vibrates. If the wire moves at high speed, the impact of the G will become stronger, and stable and smooth wire bonding may not be possible. (Objective of the Invention) The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a wire bonding method and apparatus that can perform stable wire bonding at high speed. [Summary of the Invention] In order to achieve the above object, the wire bonding method according to the present invention provides drive control between two points for the vertical movement of the bonding table and the horizontal movement of the horizontal movement table. It is characterized in that it is performed based on a drive pattern that is substantially similar to a predetermined reference drive pattern that corresponds to a straight line distance. ° Further, the vertical drive section of the bonding tool and the horizontal drive section of the horizontal movement table of the wire bonding apparatus according to the present invention each include a drive means, a storage section that stores a predetermined reference drive pattern, a movement start point and a movement end point. a drive pattern generating section that generates a drive pattern substantially similar to the predetermined reference drive pattern according to the linear distance between points, and controlling the drive means for each drive pattern from the drive pattern generation section. The invention is characterized in that it has a drive control section. (Embodiments of the Invention) First Embodiment A wire bonding apparatus according to a first embodiment of the present invention is shown in FIG. A bonding head J unit 4 is mounted on the XY team 3 which can control the drive motor 1 in the Y direction and the drive in the Y direction in the XYh direction by one motor 2. A bonding tool 6 through which the hair 75 is passed is provided. The bonding tool 6 is attached to a bonding arm 8 that swings around a fulcrum 7. A swinging arm 9 swinging about a fulcrum 7 is installed. By rotating the shaft of the eccentric pin 11 in forward and reverse directions with the drive motor 10, it is possible to move the swing arm 9 in the vertical direction, that is, in the Z direction. When the swing arm 9 moves in the vertical direction, the clamp arm 12, bonding arm lock pin 13, and bonding arm 8 connected thereto also move in the vertical direction. The Z-direction drive motor 10 is provided with a rotary encoder (not shown) for detecting its rotation angle, and the height of the bonding shell 6 can be detected from the rotation angle. The fulcrum 7 is a double axis that serves as the fulcrum for both the bonding arm 8 and the swinging arm 9, and the movement of the swinging arm 9 is controlled by the arm By pressing the bonding arm 15, the signal is transmitted to the bonding arm 8. In addition to the arm lock solenoid 14, the sub bonding arm 15 and the swing arm 9 are
It is pulled by the force generated by the linear motor 16. When moving the bonding arm 8 up and down at high speed, the arm lock solenoid 14 locks the bonding arm 8. When joining the bonding wire, use the bonding tool 6 comes into contact with the bonding member, and the sub bonding arm 15 comes off from the bonding arm lock pin 13. At this time, the sub bonding arm 15
The force necessary for bonding is applied by the near motor 16 to the wire that clamps the bonding wire 5.
7 Clamp 17 and clamp solenoid 18 are clamps)
A similar clamp solenoid 25 and a clamp solenoid 26 provided on the arm 12 are provided on the fixed arm 27. Next, the wire bonding device attached to this lie 1 bonding neck will be explained with reference to FIGS. 2(a) and ([)). First, a ball is formed at the tip of the wire V5 coming out of the bonding tool 6 (a-, 5-ch), and the bonding tool 6 is moved to the first bonding position z on the wire clamp 17. At this time, the wire clamp 25]
Bonding is done by closing and avoiding friction between the wire and the wire rod 75 ■ Hold the ball at the tip of the shell 6 and press the top U
(time O). When the first bonding is completed, bonding 1 [shell 6 and wire A7 clamp 17 are both 1-1 1] and attach the wire of the required length to bonding T shell 6.
Drawer 71 (time O). During this time, the XY table 3 moves from the first bonding position to the second bonding position. The suspension 11 of the bonding arm 6 is determined from the distance M L between the first bonding position and the second bonding position as shown in the following equation. The relationship between ``1'' and 1 is H = (1, 5
−2,0)xL+α. Here, α is a value determined empirically. Next, the bonding tool 6 is gradually lowered (time point 2), and the wire 5 is bonded to the second bonding position (time point 2). Konotogiwai A7 Clamb 25
is open. When the bonding is completed, the bonding shell is placed at the upper 91 CnY point (■), the - mouth is stopped, the soi 1 clamp 17 is closed, and the wire is cut by applying it to - again (time point -). When the bonding T shell 6 finishes rising, a ball is formed at the tip of the wire by the H2O2 torch or the electric torch 21 (time point 2), and one bonding process is completed. The outline of the vertical movement of the bonding tool 6 and the drive of the XY table 3 of the wire bonding apparatus according to this embodiment is as described above, but the drive locus of the movement "y" is different from that of the conventional b. A drive control unit that can be driven is shown in Fig. 3. In this embodiment, this drive control unit includes a drive motor 10 that moves the swing arm 9 up and down, an X-axis drive motor 1 that moves the XY table 3, and a Y-axis drive motor 1 that moves the swing arm 9 up and down. The drive motors 1, 2, and 10 are respectively provided in the drive motor 2. The drive motors 1, 2. 1!1
1 shall be proportional. In addition, bonding go shell 6
Regarding the technique of proportionalizing the moving distance of the ten-wheel movement and the rotation angle of the ten-wheel drive, there is a patent application filed by the same applicant in 1982-920.
It is described in No. 25. Electric power to the motor M is supplied from a servo amplifier 38. 1 to motor M. A generator 35 that generates a voltage proportional to the rotation angle L and a rotary pulse encoder 36 that generates pulses corresponding to the rotation direction and rotation angle lα are directly connected on the same axis. The voltage output from the di-I generator 35 is directly negatively fed back to the servo amplifier 38, forming an independent revolube. The pulse counter 37 counts the pulse train sent from the pulse encoder 36 while distinguishing the direction of rotation. The CPU 31 reads the contents of the pulse counter 37 at predetermined time intervals, calculates the difference between the 11 count values, and adds or subtracts this difference to the old current position data (EXDT) in the menu 32C. , takes a new current position of the driven object. On the other hand, the target position -12= (TARG) of the driven object is stored in the memory 32 (j), and the CPU 31 calculates the difference between this target position and the new current position, and calculates this as a deviation value (to IE
The CPU 31 stores it in the memory 32e as N).
- I EN = T A RG - E X P T
= 0, the absolute log output amount according to l-I E N is determined by a predetermined calculation, and this is applied to the servo amplifier 38.
Output to. When the driven object K is in a stopped state, T
A RG 4= E X P T,! : Natte Ori,
If it is desired to move the driven object K, the target position may be changed. In this example, these data (T
ARG, EXPT, 1-IEN, etc.) indicates the number of pulses generated by the pulse encoder 35. Next, a case where the driven object is moved by a distance S will be explained. CPLJ31 is the moving distance given in memory 32b @
The number of updates of the target position is determined from S and stored in the memory 32f as target update data (ΔSi) as shown in FIG. Here, as shown in FIG. 5(a), the movement locus of the driven object is set to be a cycloidal curve, for example, as shown in the following equation. △5=SX ・・・・・・ (1) Here, T[, 1 total movement interval, Δ1゛ is the number of updates n
This is the drive unit time obtained by dividing the total travel time T by . memory 3
11 update data (ΔSi) is determined based on this formula written in 2a and stored in the memory 32f. If the trajectory data of the marker W is converted to the Idal curve as shown in equation (1), the moving trajectory is shown in Figure 5 (a), and the velocity V is shown in Figure 5 (b). So'/f,
The acceleration α increases as shown in FIG. 5(C). Acceleration α
has a sinusoidal change and does not change abruptly, so there is less load on the motor M and less impact. Note that the acceleration α
If trb changes rapidly, other drive curves e are also suitable. For example, there are a 111 string cam curve and a modified trapezoidal cam curve. The CPU 31 sequentially reads the target update data ΔS1 from the memory 2f at intervals of a predetermined lli time Δ1, =
1 - Add this to the target position. After setting the final target position,
As soon as the current (+position (EXPT)) becomes the II target position TΔRG, the movement to the driven object is completed. In this embodiment, the standard locus of No. 1 memory 32a is
-C transforms into a similar shape depending on the straight line distance S of b. Note that several types of standard trajectories may be stored in the memory 32a and selected according to the purpose of operation. In this embodiment, since the drive can be controlled based on the standard trajectory, the cam movement theory allows for low impact and low impact at high speed.
Low-vibration drive is possible. The first one! 1 Example Next, a wire bonding apparatus according to a second embodiment of the present invention is shown in FIG. In this embodiment, the bonding arm on which the bonding tool is installed and the clamp arm on which the wire clamp is installed can be driven independently, and each drive unit is constructed using the technology of the above-mentioned Japanese Patent Application No. 59-92025. :This is an improvement so that the rotation angle and the amount of movement are proportional. A rotary encoder (not shown) and a force l\203 are attached to the rotating shaft 202 of a motor (not shown) for driving the bonding T tool 213 downward. The bonding arm 211 is connected to the swinging arm 206 by a support shaft 209. An I:L cam follower 205 is provided on the swing arm 206, and the cam follower 205 is in contact with the cam 203. In addition, the 15-motion arm 206 has an auxiliary arm 208.
is provided. At one end of this auxiliary arm 208; b
A cam follower 204 is attached. Cam 203 is sandwiched between cam followers 204 and 205. A spring 210 is provided between the swing arm 206 and the auxiliary arm 208 to apply a constant preload to the cam follower 20/1.205. The bonding arm 211 is connected to the swing arm 2 by the support shaft 209.
It is connected to 06. The bonding arm 211 is
It is held by a magnet 217, a voice-1 motor which is connected to the moving wheel 216, and a spring 218. A pin 223 is provided near the end 221 of the bonding arm 211 to prevent rotation of the bonding arm 211. A capacitive lens +j222 for detecting the movement of this end portion 221 is provided. When the bonding tool 213 hits the bonding position, the bonding arm 211 rotates slightly and the end 2
21 and the guest room sensor 222 changes. By detecting this gap change with the container lens 222, the bonding time can be determined. Ultrasonic oscillation is started from this time and ultrasonic bonding is performed. A rotary encoder (not shown) and a cam 243 are attached to a rotating shaft 242 of a motor (not shown) for vertically driving the upper clamp 252 and the lower clamp 257I. One of the clamp arms 246 is connected to the two arms 2.
It is divided into 51 and 253 clamps, respectively.
254 is installed. A cam follower 245 is provided at the other end of the clamp arm 246, and a cam follower 245 is provided at the other end of the clamp arm 246.
It is in contact with 3. J: Clamp 7-me 2/I6 (
J auxiliary arm 2/I8 is provided, and this auxiliary arm 2/I8 is provided.
A force 11) AII power 244 is also applied to one end of I8.
I'm being treated. A spring 250 is installed between the cam arm 711 and the auxiliary arm 248, such as the clamp arm 27I6 and the auxiliary arm 248, to apply a certain preload to the cam follower 2A/1.245. . The bonding wire A7230 pulled out from the spool (U not shown) is attached to the upper clamp 252 and the lower clamp 254.
It passes through and comes out from the tip of the bonding tool 213. A guide 2 is installed between the upper clamp 252 and the lower clamp 254.
32 is set (). A guide 234 is also provided just above the upper clamp 252. In order to always pull the bonding wire A7230 with a constant tension, use the T-ar nozzle 236.
Air is being blown from. Next, the YX7 bonding method according to this embodiment will be explained using FIGS. 7(a) and 7(b). First, the ball formed at the tip of the bonding wire 7230 is held in the tip of the bonding tool 4213 by closing the upper clamp 252 and lowering the bonding tool 213 (time point Δ). Next, the upper clamp 252 and the lower clamp 25
4, the bonding tool 213 moves down along the trajectory Z1 and Z2 for a distance of v s 1 and presses the ball at the first bonding position H of the semiconductor pellet 220 directly below for the duration of the bonding time. Ultrasonic bonding (time point B). Next, the bonding tool 213 is raised slightly to -, the upper clamp 254 is opened, the bonding tool 213 is moved in a direction relatively away from the second bonding position, and then the bonding tool 213 is moved toward the second bonding position (time C). ). Here, the second bonding cycle is close to the semiconductor pellet 220 and C! ii! It is provided on the ff2 external terminal. The operation of relatively separating the bonding tool 213 from the second bonding position is performed using the X equipped with the bonding tool 213.
This is done by moving the Y table 200. Next, the upper clamp 252 is closed for a predetermined amount of time 4-
J descend and remove the length H0 required for erection from the spool 249.
Pull out the bonding wire 230. In synchronization with this withdrawal of the bonding wire 230, the bonding tool 231 is moved up by a predetermined distance S along the trajectory 73 (time point D). Next, the bonding tool 213 is moved along the trajectory Z4 toward the second bonding position (time point [). When the bonding tool 213 reaches above the second bonding position, a bonding wire 230 having a length ti C necessary for construction is supplied between the bonding IU 213 and the first bonding position. With the upper clamp 252 and lower clamp 2511 open, the bonding tool 213 is lowered to the second bonding position along the trajectory Z5, and the bonding wire 23
0 is pulled, the bonding wire 230 is connected (time point F). Next, with the lower clamp 254 closed, the bonding shell 213 is raised along the trajectory Z6 by a predetermined distance of 1tlls (at time G), the bonding shell 213 is moved up to the bonding shell 213 by a predetermined distance of 1tlls.
- Raise the upper clamp 252 and the lower clamp 254 so that the bonding wire V7230 for forming the next ball protrudes from the 213 (point 1-1).
). After that, a ball is formed by the torch 255 at the tip of the bonding wire 230 protruding from the bonding tool 213 (time point I) In the above operation, the trajectory of the vertical drive of the bonding tool 213 z , z , z
4. As in the first embodiment, the movement along Z6 is performed according to a curve such as a zykroidal curve that causes less Ili impact and allows high-speed driving, and moves along the trajectory Z2. Movement along Z5 is done by a low speed drive. The movement of the XY table 200 will be explained in more detail using FIGS. 7 and 8. After bonding to the first bonding position, the bonding tool 213 begins to rise along the trajectory Z3. When time T5 elapses after the start of this upward movement, the XY table 200 starts moving, and ends the movement after time T1 elapses. This time T1 is determined based on the standard speed curve based on the straight line distance MI OQ from the first bonding position O to the second bonding position Q, and the trajectory data of the pillow Ql. The table 200 is moved by a distance 1illISxo in the X-axis direction and by a distance If S in the Y-axis direction.The speed curve of the X-axis drive in this case is Vxo (Fig. 8(b)
)) Speed curve of Y-axis drive) becomes vvo (Fig. 8(C)), and each required time is lower than X. , TVo are equal to time T1. Therefore, the movement of the XY table 200 from the first bonding position O to the second bonding position Q 1II+
The trace is a straight line created by combining the Xll1ll and Y-axis movements. If the second bonding position is P, the distance in the X-axis direction is 1, and the distance in the SY-axis direction - 1 is S7. , yp1 The speed curve is Vxp” yp, and the required time is T xp
'T do↑ru. The required time Tx, is equal to TV, and the straight line p distance 1! Depending on the ratio of lit OP to OQ, the time T is shorter. Bonding that forms a bonding loop ■Shell 213
The time required along the trajectory 73 and Z4 T -+-74
is determined by the moving distance T of the XY'7'-pull 200, and is driven in the 1-down direction (7 directions) on the 1-idal curve by the distance 111 S and the intercostal space T -+-T. In the embodiment, the distances 11iIIS6 and S7 are predetermined in order to determine the loop shape of the bonding Y\7, which determines the required time 1'5 and ·T4.Also, 9[! gill S2 is the first bonding position and the straight line distance IIIt to the second bonding position. This distance S2 makes it difficult to avoid changing the distances S6 and 87. In addition, in order to change the shape of the bonding wire,
When moving the XY table 200 from the bonding position to the second bonding position, there are cases where the XY table 200 is moved away from the table and then moved to the second bonding position (see Japanese Patent Application No. 58-2/14120). The above control can also be used to move the XY table in such a direction that it is once separated. According to this embodiment, the movement of the XY table can be driven in a similar manner regardless of the direction of movement, and the locus A can be made to follow a straight line. Therefore, a stable loop shape is obtained, and there is no difference in acceleration/deceleration in the direction of movement, making it possible to increase the speed to the permissible limit. Also-
1- Perform the same control in the downward direction (from 2, the trajectory of the shellfish became similar and stable) 1
-A curved shape can be obtained. [Effects of the Invention] As described above, according to the present invention, it was decided to perform bonding with a drive pattern similar to the standard drive pattern.■ The vertical drive of the shellfish and the horizontal drive of the horizontal drive table were carried out, so a stable drive at high speed could be achieved. 1 Fbon γ-ing can be performed.

[Brief explanation of the drawing]

FIG. 1 shows a wire bonding apparatus according to a first embodiment of the present invention. 1, FIG. 2 is a dimensional diagram showing the operation of the wire bonding apparatus, FIG. 3 is a block diagram of the drive control section of the wire bonding apparatus, and FIG. 4 is a side view of the drive control section of the wire bonding apparatus.
5 is a diagram showing the operation of the drive control IPJl, FIG. 6 is a side view of the main parts of the wire bonding apparatus according to the second embodiment of the present invention, and FIG. 7 is a memory map of the single update data memory. , FIG. 8 shows the operation of the same wire bonding apparatus.
FIG. 1 is a diagram showing the operation of a conventional wire bonding device. 1.2... Drive motor, 3... XY table, 4.
... bonding head units] ~, 5... bonding wire, 6... bonding tool, 7... fulcrum, 8... bonding arm, 9... rocking arm,
10... Drive E-event, 11... Eccentric pin, 12...
・Clamp arm, 13... Bonding arm lock pin, 14... Arm lock solenoid, 15...
・Sub-bonding arm, 16...Linear motor, 1
7.25... Wire clamp, 18.26... Clamp solenoid, 19... Spool, 21... Torch. Applicant's agent Kiyoshi Inomata ＾ ＾−
〇 〇〆－〆） ”KO Q Heno ζノ”!”R Procedural amendment May 20, 1985 Manabu Shiga, Commissioner of the License Agency Display of the case 1985 Patent application No. 67606 Name of the invention Wire bonding method and Relationship with the device amendment case Patent applicant (307) Toshiba Corporation Agent Specification and drawings. Contents of correction

Claims (1)

[Claims] 1. The bonding wire is bonded to the semiconductor pellet and the external terminal by driving the horizontal movement table on which the bonding tool is mounted while driving the bonding tool holding the bonding wire up and down. In the wire bonding method for electrically connecting, drive control between two points in vertical movement of the bonding tool and horizontal movement of the horizontal movement table is performed by the two points.
A wire bonding method characterized in that wire bonding is performed based on a drive pattern that is substantially similar to a predetermined reference drive pattern depending on the straight-line distance between points. 2. The method according to claim 1, wherein the predetermined reference drive pattern has a change curve of movement amount with respect to movement time that is a single chord cam curve, a cycloid cam curve, or a modified trapezoidal cam curve. wire bonding method. 3. In the method according to claim 1 or 2, when the horizontal movement table is horizontally moved by an X-axis drive and a Y-axis drive that are perpendicular to each other,
A wire bonding method characterized in that shaft drives start and end almost simultaneously. 4. A bonding tool that holds the bonding wire, and a vertical drive section that drives the bonding tool up and down,
It includes a horizontal movement table on which the bonding tool is mounted, and a horizontal drive section that drives the horizontal movement table horizontally. In a wire bonding device that electrically connects the bonding wire to a semiconductor pellet and an external terminal by horizontally moving the bonding wire, the vertical drive section and the horizontal drive section each have a drive means and a predetermined reference drive. a storage unit that stores patterns; a drive pattern generation unit that generates a drive pattern that is substantially similar to the predetermined reference drive pattern according to the linear distance between a movement start point and a movement end point; a drive control section that controls the drive means based on a drive pattern of the wire bonding apparatus. 5. The device according to claim 4, wherein the predetermined reference drive pattern has a change curve of movement amount with respect to movement time that is a single chord cam curve, a cycloid cam curve, or a modified trapezoidal cam curve. wire bonding equipment. 6. In the device according to claim 4 or 5, the drive means of the horizontal drive section may be
It has an axis drive means and a Y-axis drive means, and the drive control unit controls the X-axis drive means and the Y-axis drive means so that the X-axis drive and the Y-axis drive start almost simultaneously and end almost at the same time. A wire bonding device characterized by: