JPS6080231A - Lead frame automatic feeding positioning mechanism in semiconductor element bonding apparatus - Google Patents

Abstract

PURPOSE:To realize application of titled mechanism even when even when frame or shape is changed by detecting location of lands of lead frame, calculating positional displacement between such detected location and center position and correcting the position of lead frame. CONSTITUTION:A position detection circuit 40 detects that the center of land of lead frame lies in which photodiode and then inputs such data to a comparison/ operation circuit 41. The information of photodiode at the center position is stored in the memory circuit 42 and this information is input to the circuit 41 for each output from the circuit 40. The circuit 41 compares and calculates both inputs and inputs a difference information, namely position displacement of pertinent land is to the motor drive circuit 43. The circuit 43 shifts the lead frame as much as such positional difference for correction and also shifts the lead frame up to the bonding position. Thereby large scale replacement of parts for each change of the shape and size of lead frame is no longer necessary.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic feed positioning machine jmK for a lead frame in a bonding apparatus for sequentially bonding semiconductor elements to lands of a lead frame. figure(
a) to (e) K are used.

Fig. 1 (al) K shows an example of the outline of a lead frame for a semiconductor device; c, 2 shows a lead frame to which a lead frame conductor chip is bonded; 4, the shaft 61 rotates in a predetermined direction.The shaft 61 is equipped with a lead frame feeding cam 5, a feed pawl up/down cam 6, and a vertical cam 6a of clamp 1. The vertical cam 6 is connected to the connecting part 62.
◎Feed pawl feed 4 is connected to the feed pawl feed shaft 8 via
+118 is provided with a feed claw holder 9.9 at a predetermined interval, and a clamp plate 11 that moves up and down from the clamp up and down cam 6aK is provided at an intermediate position of the feed claw holder 9.9. , 1 (b) In the state shown by K, m1 (c), (d
)K, the second feed claw 10.10 attached to the feed claw holder 9.9 is inserted into the twinkling guide hole 3°3 formed on the side of the lead frame 5 shown in FIG. 1(al). The clamp plates 11 are opposed to each other at a predetermined distance above, and clamp the lands 2 of the lead frame l, and the positioning pins 12 provided thereon are inserted into the guide holes 13 formed on the side surfaces of the leads 71/-mul. Inserted 0 Land 2 in that state
A semiconductor chip is bonded to. Tanabata for sending off 4
The shaft 61 rotates by driving the feed claw 10.
10 is lowered by the action of the feed pawl up/down cam 60, and on the contrary, the lead frame 1 is clamped by the clamp plate Xi at 81#, and the KAti base is set so that the positioning pin 12 is raised as the lead frame 10 is lowered. Feed by the action of the lead frame feed cam 50! 1118 is shown in Figure 1 (b
) is moved to the right at h, and in that state the feed claw t
o and io are respectively inserted into the feed pawl kite holes 3 which were facing the pressure side before movement, and when the feed motor 4 controls the rotation, the feed shaft 8 moves to the right by a predetermined amount from hK. During the moving process, the lead frame l is moved by the feed claw 10.1O.
From K, the lead frame guide hole 3 is locked and the feed motor 4 continues to rotate, and the clamp plate 11 is lowered by the action of the clamp plate vertical cam 60. , the land 2 of the lead frame is clamped, and the positioning pin 12. is inserted into the guide hole 13.
As the 0 feed motor 4 into which 12 is inserted continues to rotate, the feed shaft 8 moves a predetermined amount to the left.〇Feed shaft 8
reaches the original position and the feed motor stops. In this stopped state, the feed pawl 10.10 is already unlatched to the kite hole 3, and the clamp ill sufficiently clamps the next land of the lead frame, and Is the positioning bin 12 a positioning guy? By fitting into L 13, the next land is placed in the bonding position and the semiconductor chip is bonded onto said land. After the bonding is completed, by repeating the above-mentioned operations, the semiconductor chips are sequentially bonded onto the lands while the lead frame 1 is intermittently fed at predetermined intervals.This method is suitable for lead frame transfer. Cam, feed claw upper and lower cam, feed claw holder,
Since the clamp plate, positioning bottle, etc. are all composed of mechanical parts, high precision is required for processing and assembling them, and the mechanical adjustment of the device itself requires considerable time and effort. i et al of the frame itself,
Smooth work may not be possible due to bending, etc., and this type of lead frame has a wide variety of shapes, so when applying to a different lead frame, it is necessary to adjust the positioning pin, clamp plate, and feed claw each time. There is a problem in that related parts such as cams must be newly set.

The present invention has been made in order to solve the above-mentioned problems of conventional bonding devices of this type.

The present invention will be explained according to the embodiment shown in FIGS. 2(a) to 4. In FIGS. The respective shafts 161 and 221 are
As shown in Fig. 2 (cl), for example Fig. 2(b)
The 0 pulley 28, which is fixed to the pulleys 28 and 30 on the back side of the machine, and a belt 32' is hung between the pulleys 28 and 30, is a driving googly that is rotationally driven by the supply side step motor 14. . Reference numeral 17 denotes a presser roller that is paired with the drive pulley 16. The presser roller 17 is rotatably attached to one end of the connecting portion 171, and the other end of the retardation member 171 is rotatably inserted through the mounting portion 27. Na axis 2
It is fixed to 6. The presser roller 17 can be moved up and down about the shaft 26, and the lead frame l is set to pass between the rotating roller 16 and the presser roller 17. Therefore, the lead frame l is in a state where the boot IJ28 is driven. Then, by displacing the presser roller 17 downward and pressing it against the rotary row 216, the sheet is fed while being held between the valve roller 17 and the rotary roller 16, and the feeding is stopped by displacing the presser roller 17 upward. 22 is a rotating roller having the same configuration as the rotating roller 16 and whose shaft is fixed to the pulley 30; 23 is a presser roller that is paired with the rotating roller 22 and has the same configuration as the presser roller 17; 231 is a connecting member 171 A connecting member having the same configuration as 31
The mounting part 29, which is the same component as the mounting member 27, is the same component as the shaft 26 attached to the mounting part a1. Reference numeral 15 denotes a lead frame confirmation sensor on the supply side made of, for example, a light emitting diode phototransistor. When it is fed to position 15, it is detected and the supply side step motor 14 and solenoid 33 are activated. The drive roller 16 is rotationally driven by the rotation of the pulley 28 by the operation of the supply side step motor 14, and the presser roller 17 is displaced downward by the operation of the solenoid 33mb, and the lead frame l is moved by the pair of drive rollers J mentioned above.
6 and presser roller 17 at high speed.
When the land 2 located at the leading edge of the lead frame 1 comes within the detection range of the lead frame position detection unit 18 provided in front of the feed path, the step motor 14 on the supply side that is sent in the 0 direction operates at low speed. 0 In the position detecting section 18, the lead frame 10
The position of the land 2 is corrected. The position detection calculation and position correction operation of the land 2 of the lead frame 1 by the lead frame position detecting section 58 will be described in detail with reference to FIGS. 3(a) to 4.

The lead frame position detection calculation 8 is provided above the lead frame feeding path 32. A light-shielding plate 38 is composed of a light-receiving sensor 181 made of a photodiode or the like, and a light-emitting element 39 provided below one passage facing the light-receiving sensor 181. On the surface facing the longitudinal center of the path 32, a plurality of photodiodes b constituting the light receiving sensor 81 are arranged in parallel at right angles to the longitudinal direction of the path at intervals of, for example, about 25μ. The light emitted from the light emitting element 39 is detected by the light receiving sensor 181 at the device detection unit 18.
Although the direction is irradiated, land 2 of lead frame 5
is located between the light emitting element 39 and the light receiving sensor 181, the light is blocked by the land 2 interposed between them,
The blocked light is not received by the light receiving sensor 181K.

Therefore, as shown in the enlarged example in Figure 3 (C),
Photodiode b whose light is blocked by land 2 is ′o
1. Unobstructed photodiode b detects #1'. For example, if the number of photodiodes arranged is 512, the center is the 256th photodiode from the left in Fig. 3 (cl K), and when the center of land 2 overlaps with the 256th position, It is determined that the land 2 is at the center position.Therefore, by detecting from which diode to which diode 1 is 101, it is determined whether or not the land 2 has stopped at the center position. For example, f3 diagram (c
In the case of land 2 shown by a solid line in llc, if 15
If the distance from the 0th photodiode to the 362nd@th photodiode is 'o', then 362-150 = 21
2 or 0, the center C is 150+” 2/2= 256
Since it overlaps with the 357th W photodiode, it is judged to be at the center position, and the dotted line indicates 21°. ba357-145=
212 is 101, but its center c1 is 145+2"
, (=251251) Since it overlaps with the 1st diode, it turns out that it is located to the left by a distance corresponding to the 251-256≠-5 photodiode.

FIG. 4 shows a system for the comparison operation and the tILt correction. Reference numeral 4o denotes a position detection circuit section, and the position detection circuit section 4o detects the number of photodiodes 101 and determines the number of photodiodes 101 and 101. , it is detected whether the center of the land 2 is located above the i-th photodiode, and the comparison/arithmetic circuit 4J [manually performs the detection]. In the case of the above-mentioned example, the information of the 256th photodiode is stored, and the information is manually entered into the comparison calculation circuit 41 every time the VT detection circuit 4o outputs the information. In the path 41, the internal inputs are compared and calculated, and the difference, or difference information expressed as the number of steps, is inputted to the motor drive circuit 43, and the supply side step motor 14 is driven by a predetermined amount to move the land to the center position. From the 0 read frame position detection unit 58 to be moved to
A tool 20 is provided above the path at a certain distance in front, and a bonding column 21 is provided in the path facing the lead frame position detection section 58 and the tool 20. In this case, the lead frame position detection section 58 Except for the 58 and the tool 20, the other components are listed on the non-table 19.FLIi! i], and the main table 59 is set to be movable along the longitudinal center line of the passage. In this state, by driving the step motor 34 by a predetermined amount, the main tape # 19 is the second
In Figures (a) and (b), the land is moved a predetermined amount to the right in K, and the land whose position has been already corrected is positioned directly below the tool 20.

Since the distance between the center point of the lead frame l and the tool 20 after position correction is as set in advance (distance L),
It is easy to drive and control the step mo/34 so that the land 2 is directly under the tool 20. In this state, bond the semiconductor tip onto the land 2 using the tool 2o. After the bonding is completed, The step motor 34 is driven in the opposite direction to that described above to move the land 2 directly below the lead frame detection section 18.Then, by repeating the above-mentioned operation, the semiconductor chips are sequentially bonded to the land 2 of the lead frame l. 0 That is, the step motor 14 is driven so that when the land 2 that has completed bonding returns to the lead frame position detection unit 18 [Q], the land 2 one position behind it can be moved to the position of the lead frame position detection unit 18. control.

The following 0 is performed by repeating the above-mentioned operations.
The bonding of the half-quad chips to the land 2 of the lead frame 1 progresses in sequence, and when the lead 2 frame is sent forward and the supply side confirmation sensor 15 no longer detects the lead frame, the power to the solenoid 33 is cut off. However, at that time, the storage side lead frame detection sensor 24 detects the lead frame 1 in question.
The distance between the supply side confirmation sensor 15 and the storage sensor 24 is set by the length of the lead frame 5. The solenoid 33 is activated by the detection of the lead frame l of the storage side confirmation sensor 24. It becomes a movement,
The holding roller 23 on the storage side is displaced downward. That is, at this time, the supply side valve roller 17 and the drive roller 1BK
The clamping feeding of the lead frame is replaced by the clamping feeding by a pair of storage-side valve rollers 23 and rotating rollers 22.0 Then, the subsequent bonding of the semiconductor chip to the lands of the lead frame 5 is performed in the same manner as described above. On the other hand, a storage start sensor 37 provided along the feed path 32 in front of the storage side confirmation sensor 24
Klf4 is set so that the bonding at the last land of the lead frame is completed when the lead 7 detects the tip of the lead frame 1, and when the storage start sensor 37 detects the tip of the lead frame, a separate Klf4 is set. The lead frame l is ejected to the storage side by the feeding mechanism.

In the above embodiment, after the lead frame position detection unit 18 corrects the position of the lead frame, the step motor 34 is driven to move the main table 19 so that the land 2 is directly below the tool, that is, the distance is An example has been described in which the main table 19 is moved by a certain amount to perform bonding, and then the main table 19 is returned to its original position. The one-step motor 34 is driven and controlled so that the land 2 is positioned forward by a distance equal to the sum of the positional deviations ΔX and L, and the land is moved directly below the tool.

According to the present invention, the position of the land of the lead frame is detected and the position and deviation between the detected position and the center position are detected by the image sensor 1BK, and the lead frame is moved by an amount corresponding to the position deviation to correct it. 4? Because of this structure, even if one dimension of the shape of the lead frame to which a semiconductor chip is to be bonded is lost, the condition that the lead frame can be moved so that its longitudinal center line overlaps the center line of the feed path is satisfied. The image sensor has a general-purpose 1+J function for various shapes, and all that is left to do is adjust the drive amount of the feed drive mechanism 14 according to the pitch between the lands. There is no need to extensively replace parts each time the dimensions differ.Also, unlike the conventional mechanical claw feeding method,
Since this method compares and calculates the information detected by the image sensor, the positioning accuracy of the lead frame is improved accordingly, and therefore the bonding accuracy can be improved. Furthermore, as is clear from the above, in the present invention, compared to the conventional mechanical system, the number of mechanical assembly parts is extremely small, and the assembly and adjustment time can be reduced by 1r11. The technical effects of this method, such as being able to shorten the redesign time and not being affected by the processing accuracy of the lead frame, are described by W.J.

[Brief explanation of drawings]

Fig. 1(a) is a plan view showing an example of a lead frame, Fig. 1(b) is a plan view showing a conventional lead frame feeding and positioning device in bonding equipment #LK, and Fig. 1(c) is a plan view showing an example of a lead frame.
is the front view of Figure 1 (b), Figure 1 (the mountain is Figure 1 fbl)
, (c) is a plan view showing the state in which the land of the lead frame is clamped by the clamp plate, and Fig. 1 (e) is l'
E1(d) is a front view, FIG. 2(a) is a plan view showing an embodiment of the present invention, FIG. 2(b) is a front view of FIG. 2(a),
Figure 2 (c) is a perspective view showing the relationship between the presser roller, rotary roller and pulley in @2 causes (a) and (b) K, and Figure 3 (a) is a perspective view showing the relationship between the presser roller, rotary roller and pulley. JF plane view showing the detection part, Figure 13(b) is -f in Figure 3(a)
The front view of the ib notch, detailed figure 3 (c) shows the land position detection and position fk?
Id Masasaku) An enlarged plan view for explaining d. Figure 144 shows lead frame land position detection,
FIG. 1 is a block diagram showing correction-like accommodation. l... Lead frame, 2... Land, 58...
・Position detection unit, 36.17.22.23...Feeding mechanism, 4]...Comparison calculation circuit, 43...Correction drive mechanism part il1 (a) f Figure 1 (b) 1st Figure (e) Figure 1 (d) Figure 1 (e)

Claims (1)

[Scope of Claims] In a bonding device for bonding a semiconductor element onto the land of a lead frame, a feeding mechanism that feeds the lead frame so that the lands of the lead frame are sequentially positioned at a position detection unit consisting of an image sensor; The first position detection section consists of a comparison calculation circuit and a correction drive m structure. ! In order to detect the center point in the feed direction of the land of the lead frame fed by 11sK, the comparison calculation circuit is predetermined between the center signal of the land detected by the position detection section and the body position detection section. The Kfg is configured to perform a comparison calculation with the bonding normal position information that has been calculated, and the correction drive m component corrects the relay frame by an amount corresponding to the position difference calculated by the comparison calculation circuit. Automatic feed positioning of a lead frame in a bonding apparatus for semiconductor solid-state elements, which is configured to adjust the positional difference and move the lead frame to the bonding position 4d f/9 n