KR20070090670A - Method for correcting die pickup position - Google Patents

Abstract

A method for correcting a position of a die pickup is provided to prevent a pickup error or bad bonding by detecting a fiducial mark of a die to be picked up at a die bonding device. A fiducial mark of a die is taught by a vision camera(S10), and teaching coordinates are compared with preset coordinates of the die to compute a variation(S30). The preset coordinates are corrected by adding or subtracting the variation to or from the preset coordinates, and the corrected preset coordinates are output. In the output step, the corrected preset coordinates are output to pick up the die by a pickup head, and the picked-up die is rotated by the variation.

Description

METHOD FOR CORRECTING DIE PICKUP POSITION}

1 is a block diagram showing a bonding apparatus for picking up by a die pickup position correction method according to an embodiment of the present invention.

2 is a flow chart showing a die pickup position correction method according to an embodiment of the present invention;

Figure 3 is an enlarged plan view of the die of the die pickup position correction method according to an embodiment of the present invention.

Figure 4 is a conceptual diagram for explaining the calculation formula of the die pickup position correction method according to an embodiment of the present invention.

<Description of Symbols for Major Parts of Drawings>

100: bonding apparatus 10: wafer stage

20: bonding head 30: flip head

40: vision camera 50: conveyor

The present invention relates to a method for correcting a die pick-up position, and more particularly, a die pick-up position that detects a physical mark of a die to be picked up by a die bonding device, and corrects the pick-up position of the die in the flip head and the bonding head. It relates to a correction method.

In general, the semiconductor device package process cuts the finished wafer into separate dies (also referred to as "chips") through a wafer fabrication process. The die is then bonded to the leadframe. After that, the terminal of the bonded die and the lead of the lead frame are connected by wires. The semiconductor device package process is completed by molding the resin or ceramic to protect the die and cutting the external lead of the lead frame.

However, in recent years, the above-mentioned wire bonding method has a limit in the trend of being light and thin and small in size, and is packaged by flip chip bonding called a solder bump method.

That is, the flip chip bonding method is to form a separate solder bump on the pad (Pad), which is an input and output terminal of the semiconductor chip, and then turn the semiconductor chip upside down to lead frame or circuit tape (hereinafter referred to as "lead frame"). ) Is directly attached to the circuit pattern of the pattern.

The flip chip bonding apparatus mainly includes a wafer stage for seating and supporting a wafer, a bonding head for bonding a die provided on a wafer on the wafer stage to a lead frame or circuit tape, and a die for picking and supplying a die on the wafer stage to the bonding head. It consists of a flip head and a vision camera that senses the position by sensing the wafer and die on the wafer stage.

The wafer is bonded to the wafer support tape which holds the wafer so that the wafer can be supported in the state of being cut into each die. The wafer is mounted on the wafer stage with the wafer supporting tape fixed to the donut-shaped wafer frame.

The wafer stage is provided to prevent the wafer from sag and to support the wafer support tape with a constant tension during die pick-up.

However, the seating position of the wafer is not accurate to the wafer stage, the wafer support tape supporting the wafer is stretched on the wafer stage, or the tension change occurs due to excessive adhesive force in the process of picking up the die on the wafer.

This will change the position of each die. That is, when the tension of the tape changes while the center setting coordinates of the die are input by the vision camera, the center of the die changes in the setting coordinates. Therefore, the pickup position is changed.

Then, the flip head picks up the die in an inverted state, and since the flip head supplies the die to the bonding head in an inverted state, the bonding head is also bonded to the lead frame in an inverted state, thereby causing a defect.

축을 별도로 마련하여 픽업위치를 보정하고 있다. 하지만 플립헤드에 별도의

축을 마련하게 되면 구성이 복잡해지고, 별도의 유지관리를 필요로 하는 문제가 있다. So to rotate the separate pickup head to correct the pickup position

A separate shaft is provided to correct the pickup position. But a separate fliphead

If the axis is provided, the configuration is complicated, there is a problem that requires separate maintenance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above necessity, and provides a die picking position correction method for detecting a die mark of a die to be picked up by a die bonding apparatus and correcting a die picking position at a flip head and a bonding head. For that purpose.

Die pickup position correction method of the present invention for achieving the above object comprises the steps of teaching the vision mark of the die with a vision camera;

Calculating a deviation by comparing the teaching coordinates with preset coordinates of the die;

Correcting by adding or subtracting the deviation to the set coordinate; And,

Outputting to be controlled by the corrected set coordinates.

Here, the vision camera senses two points of the physical mark of the die, and the physical mark is preferably located on a diagonal of the die.

,

,

계산 값은 And said

,

,

The calculated value is

,

는 웨이퍼 스테이지 회전축의 중심점의 값이다.) (here

,

Is the value of the center point of the wafer stage rotation axis.)

It is desirable to satisfy.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the following description of the present invention, the terms defined are defined in consideration of functions in the present invention, and should not be understood as a meaning of limiting the technical components of the present invention.

1 is a block diagram illustrating a bonding apparatus for picking up a die pickup position correction method according to an embodiment of the present invention.

As shown in FIG. 1, the flip chip bonding apparatus 100 includes a wafer stage 10 for seating and supporting a wafer W, and a die D provided in a wafer on the wafer stage 10. Or a bonding head 20 bonded to a circuit tape (hereinafter referred to as a "lead frame"), a flip head 30 for picking up and supplying a die D on the wafer stage 10 to the bonding head 20; And a vision camera 40 that detects the wafer W and the die D on the wafer stage 10 to recognize the position.

And a lower portion of the bonding head 20 is provided with a conveyor 50 for sequentially transferring the lead frame.

Here, the wafer stage 10 is provided to support the edge of the wafer, and the wafer ring guide 11 is provided at the center. The bonding head 20 is provided to operate in the X, Y, and Z directions.

In addition, the flip head 30 is positioned above the wafer stage 10 to sequentially pick up the die D of the wafer W and supply it to the bonding head 20. Thus, the flip head 30 picks up the lower die D, rotates it to the upper side, and directly supplies it to the bonding head 20. At this time, it operates to be the same position as the pick-up position of the flip head, the backup pin 31 is provided so that it can be supported directly under the die (D) when picking up the die (D).

In addition, the vision camera 40 operates in the same manner as the pickup head 30 or is fixed to the pickup head 30 so as to detect a pickup position of the pickup head 30.

Hereinafter, the operation of the bonding apparatus of the present invention will be described with reference to the configuration of FIG. 1.

Here, the wafer W supplied to the bonding apparatus 100 is supplied with a die D of a predetermined size separated. The die D in the separated state is supplied by being bonded to the wafer support tape 1 so that the die D can be supported while maintaining the shape of the wafer W. The wafer W is supplied to the donut-shaped wafer frame 2 with the edge of the wafer support tape 1 fixed.

At this time, the wafer support tape 1 is formed to have a constant tension so that the die D of the wafer W can be picked up. That is, the wafer ring guide 11 of the wafer stage 10 tightens the wafer support tape 1 between the wafer frame 2 and the wafer W. As shown in FIG.

Thereafter, the vision camera 40 teaches the position of the wafer, and the pitch and size of the die D are input, and the set coordinates for picking up each die D are calculated and input. The die D is sequentially picked up according to the set coordinates.

2 is a flowchart illustrating a die pickup position correction method according to an embodiment of the present invention. 3 is an enlarged plan view of a die of the die pickup position correction method according to an embodiment of the present invention. 4 is a conceptual diagram for explaining a calculation formula of the die pickup position correction method according to an embodiment of the present invention.

Referring to FIGS. 2 to 3, as illustrated, the vision camera 40 recognizes the first physical mark 1st on the die D (S10). In operation S20, the second physical mark 2nd is sequentially recognized. Therefore, the teaching coordinates of the first physical mark 1st and the teaching coordinates of the second physical mark 2nd are recognized by the vision camera 40.

Here, the objective mark is provided by forming any two points on the die (D). It is preferable to form a preferable duty mark position so that it may be arrange | positioned in the diagonal direction of die D. FIG. And the physical mark can vary in form (cross form, translator form, check form, etc.). Also, the physical mark may be an edge, corner or vertex of the die.

In addition, the deviation is calculated by comparing the teaching coordinates with the preset coordinates recognized by the two visual marks in the vision camera 40. The deviation is calculated in order to reduce the occurrence of bonding defects due to the change in position at the set coordinates due to the tension change and the bearing force change of the wafer support tape, and the tension change of the wafer support tape generated when the die (D) is picked up.

Accordingly, the deviation is calculated to correct the pick-up position of the die D of the flip head 30 and the bonding head 20 operating along the set coordinates by adding or subtracting from the preset setting coordinates.

, Y좌표 편차를

,

각도편차를

라 하면, The deviation is calculated by separating the coordinate deviation from the angular deviation. In order to calculate the coordinate deviation and the angular deviation of the die D, reference is made to FIG. 4, and it can be calculated by the following equation. Where the X coordinate deviation

, The Y coordinate deviation

,

Angular deviation

Say,

각도 편차는 다음 공식에 의해 산출될 수 있다.

The angle deviation can be calculated by the following formula.

And the X coordinate deviation can be calculated by the following formula.

In addition, the Y coordinate deviation can be calculated by the following formula.

,

는 웨이퍼 스테이지 회전축의 중심점의 값이다.) (here

,

Is the value of the center point of the wafer stage rotation axis.)

)를 가감하여 보정된 설정각도가 본딩헤드(20)로 출력된다.(S40)Thereafter, the coordinate deviation is added or subtracted to the preset setting coordinates as shown in the following equation to output the corrected setting coordinates to the flip head 30 so that the flip head 30 is picked up at the center of the die D. And angular deviation (

And the corrected setting angle is output to the bonding head 20. (S40)

Pickup coordinate X = Set coordinate X +

이다.Pickup coordinate Y = Set coordinate Y +

to be.

Thereafter, the corrected set coordinates of the die D are output to the flip head 30 to control the flip head 30. Thus, the flip head 30 moves to the corrected pickup coordinate to pick up the die D. (S50)

The flip head 30 picks up the die D and supplies it to the bonding head 20.

At this time, since the flip head 30 picks up the lower die D and supplies it to the upper bonding head 20, the bonding head 20 picks up the opposite side of the supplied die D.

)에 따라 기 설정각도에서 각도편차(

)를 가감하여 회전한 후 픽업한다. 이때 플립헤드(30)가 본딩헤드(20)에 다이 공급시 뒤집어서 공급하므로

각도편차는 역으로 가감된다. (S70)Therefore, the bonding head 20 is angular deviation (

Angular deviation from the preset angle

), And then pick up after rotating. At this time, since the flip head 30 supplies the die to the bonding head 20,

Angular deviation is added or subtracted inversely. (S70)

,

)에 따라 플립헤드(30)를 제어하여 보정된 정확한 설정좌표(X, Y)에서 다이(D)를 픽업하게 되고, 픽업된 다이(D)를 본딩헤드(20)가 각도편차(

)만큼 보정된 설정각도 만큼 회전한 후 픽업하게 된다. Therefore, X, Y coordinate deviation (

,

By controlling the flip head 30 according to the pick-up of the die (D) from the correct set coordinates (X, Y), the bonding head 20 is the angular deviation (

Pick up after rotating by the set angle corrected by).

)만큼 보정한 설정각도 만큼 회전하여 본딩 할 수 있다. In this case, the bonding head 20 first picks up the die D, and then the angular deviation (

It can be rotated and bonded by the set angle corrected by).

After that, the picked-up die D is placed on the lead frame R which is transported by the conveyor 50 and then flip-chip bonded.

Here, the flip head 30 supplies the die D to the bonding head 20 while the flip head 30 moves to the position of the next die D to be picked up, and the vision camera 40 is supplied to the next die. Detect the physical mark of the

After that, the process of S10 to S70 is repeated repeatedly, and the set coordinate of the die is corrected and then picked up.

The technical idea of the die pick-up position correction method of the present invention has been described above with the accompanying drawings, but this is only illustrative of the best embodiment of the present invention and is not intended to limit the present invention.

Therefore, it is obvious that any person skilled in the art can make various modifications and imitations such as dimensions, shapes, structures, etc. without departing from the scope of the technical idea of the present invention.

As described above, the die pick-up position correction method for detecting the die mark of the die to be picked up by the die bonding apparatus and correcting the die pick-up position at the flip head and the bonding head is a pickup position without any additional configuration in the die bonding apparatus. By correcting the pickup, there is an effect that can prevent pickup errors or poor bonding.

Claims (3)

Teaching a die mark of the die with a vision camera; Calculating a deviation by comparing the teaching coordinates with preset coordinates of the die; Correcting by adding or subtracting the deviation to the set coordinate; And, And outputting it to be controlled by the corrected set coordinates. The method of claim 1, A die transfer step of picking up a die from a pickup head by outputting a set coordinate corrected in the output step; And a die pick-up step of picking up the picked up die by rotating the bonding head by the deviation. The method of claim 1, The deviation (

,

,

)

(here

,

Is the value of the center point of the wafer stage rotation axis.) Die pickup position correction method characterized in that satisfying the.

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