KR101732467B1

KR101732467B1 - Bonding device, and method for detecting breakage in semiconductor die by bonding device

Info

Publication number: KR101732467B1
Application number: KR1020147033124A
Authority: KR
Inventors: 유야 토요카와
Original assignee: 가부시키가이샤 신가와
Priority date: 2013-01-23
Filing date: 2013-08-19
Publication date: 2017-05-24
Also published as: TWI512854B; CN104937702A; WO2014115359A1; CN104937702B; KR20150013613A; JP2016076505A; TW201430969A

Abstract

The die bonder 100 is provided with a back side camera (hereinafter referred to as a back side camera) for picking up an entire image including an image of the suction side image of the collet 20 that adsorbs the semiconductor die 40 and an image of the semiconductor die 40 adsorbed to the collet 20 And an image processing unit 80 for processing each image acquired by the back side camera 30. The image processing unit 80 is a unit for acquiring the image of the attraction surface of the collet 20 and the image of the semiconductor die 40 An image area delimiting means for delimiting the image area of the semiconductor die 40 in the entire image based on the brightness difference and the reference image of the semiconductor die 40; And determines that the semiconductor die is damaged if the rate of change of brightness in the scanning direction is equal to or larger than a predetermined threshold value. This effectively prevents the broken semiconductor die from being bonded and improves the quality of the semiconductor device manufactured by the die bonder 100. [

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a semiconductor die breakage detection method using a bonding apparatus and a bonding apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a bonding apparatus for detecting damage such as cracks or defects of a semiconductor die to be bonded, and a method of detecting breakage of a semiconductor die by a bonding apparatus.

BACKGROUND ART A die bonder is widely used as an apparatus for bonding a semiconductor die to a circuit board such as a lead frame. The die bonder includes a pick-up stage for picking up a semiconductor die from a wafer after dicing and a bonding stage for bonding the semiconductor die picked up from the wafer to a circuit board, and picking up and bonding the semiconductor die by a collet which is a bonding tool. More specifically, the collet picks up a semiconductor die from a wafer on a pick-up stage by sucking a semiconductor die at the tip, transfers the semiconductor die to a bonding position of the circuit board on the bonding stage, The semiconductor die is bonded (see, for example, Patent Document 1).

It is necessary to precisely match the positions of the semiconductor die and the circuit board at the time of bonding. For example, when the semiconductor die is transferred from the pick-up stage to the bonding stage by the collet, There has been proposed a method of acquiring an image of a semiconductor die and correcting the displacement of the relative position between the semiconductor die and the circuit board based on the alignment mark of the semiconductor die (see, for example, Patent Document 2).

In addition, when a reference member having a mirror and a rectangular through hole is fixed to a transfer head of a semiconductor die through an L-shaped connecting member and the semiconductor die is transported by the transfer head, The position of the semiconductor die relative to the reference component is detected, and the position of the semiconductor die on the circuit board of the semiconductor die is detected on the basis of the detection result There has been proposed a method of correcting the mounting position (see, for example, Patent Document 3).

WO2005 / 029574 Japanese Laid-Open Patent Publication No. 2010-040738 Japanese Patent Application Laid-Open No. 2007-115851

However, as described in Patent Document 1, when the semiconductor die is taken out from the wafer sheet to pick up the semiconductor die, the semiconductor die is deformed, so that a thin semiconductor die may be broken at the time of picking up. Patent Document 1 discloses a collet and pickup method in which the semiconductor die is not broken at the time of picking up, but does not describe a countermeasure in the case where the semiconductor die is broken at the time of picking up. In Patent Documents 2 and 3, the position of the semiconductor die sucked and fixed to the collet is detected and the semiconductor die is precisely bonded to a predetermined position of the circuit board before bonding. However, The action when there was was not mentioned. For this reason, in the prior art die bonders disclosed in Patent Documents 1 to 3, even if the semiconductor die is broken at the time of picking up, the semiconductor die is bonded directly onto the circuit board, causing a defect in the semiconductor device manufactured by the die bonder There was a problem.

In recent years, the thickness of the semiconductor die has become thinner, and the thickness thereof has been reduced to about 15 to 50 mu m. When such a thin semiconductor die is attracted to the collet, a part of the semiconductor die may float or bend from the attracted surface of the collet. In this case, when the image of the semiconductor die is obtained by the method described in Patent Documents 2 and 3, the brightness of the image continuously changes in accordance with the rising or bending of the semiconductor die from the attracting surface, It is difficult to discriminate between the two.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to effectively suppress the bonding of a damaged semiconductor die in a bonding apparatus, thereby improving the quality of a semiconductor device manufactured by the bonding apparatus.

A bonding apparatus of the present invention includes a camera for picking up an entire image including an image of an adsorption face of a collet that adsorbs a semiconductor die and an image of a semiconductor die adsorbed to a collet and an image processing section for processing each image acquired by the camera And the image processing section includes image area delimiting means for delimiting the lightness difference between the image of the suction face of the collet and the image of the semiconductor die and the image area of the semiconductor die in the entire image based on the reference image of the semiconductor die, And a failure detecting means for determining that the semiconductor die is damaged when the rate of change of brightness in the scanning direction is equal to or larger than a predetermined threshold value.

In the bonding apparatus of the present invention, it is preferable that the breakage detecting means is configured to set the inner portion excluding the periphery of the image area of the semiconductor die defined by the image delimiting means as the inspection region, and scan the inspection region.

A method of detecting breakage of a semiconductor die by a bonding apparatus of the present invention includes an image capturing step of capturing an entire image including an image of an adsorption face of a collet to be adsorbed on a semiconductor die and an image of a semiconductor die adsorbed on a collet, An image area demarcation step of demarcating an image area of a semiconductor die in a whole image based on a difference in brightness between a face image and an image of the semiconductor die and a reference image of the semiconductor die; And determining that the semiconductor die is broken if the rate of change of brightness in the scanning direction is equal to or greater than a predetermined threshold value.

In the method of detecting breakage of a semiconductor die by the bonding apparatus of the present invention, in the breakage detecting step, the inner portion excluding the periphery of the image region of the semiconductor die defined by the image delimiting step is set as the inspection region, .

INDUSTRIAL APPLICABILITY The present invention effectively suppresses bonding of a broken semiconductor die in a bonding apparatus and can improve the quality of a semiconductor device manufactured by a bonding apparatus.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a systematic diagram showing a configuration of a die bonder in an embodiment of the present invention. FIG.
Fig. 2 is an explanatory view showing the operation of the die bonder in the embodiment of the present invention. Fig.
3 is a flowchart showing the reference image registration operation of the die bonder in the embodiment of the present invention.
4 is a flowchart showing the breakage detecting operation of the die bonder in the embodiment of the present invention.
Fig. 5 is an explanatory view showing a take-out operation of a reference image of a die bonder in the embodiment of the present invention. Fig.
Fig. 6 is an explanatory view showing the image area delimiting operation of the die bonder in the embodiment of the present invention. Fig.
7 is an explanatory diagram showing an image area delimiting operation of the die bonder in the embodiment of the present invention.
8 is an explanatory view showing the setting operation of the inspection area of the die bonder in the embodiment of the present invention.
Fig. 9 is an explanatory view showing the scanning of the inspection area of the die bonder in the embodiment of the present invention. Fig.
10 is an explanatory view showing a change in brightness in the scanning direction at the time of detecting breakage of the die bonder in the embodiment of the present invention.
11 is an explanatory diagram showing a change in brightness in the scanning direction at the time of detecting breakage of the die bonder in the embodiment of the present invention.

Best Mode for Carrying Out the Invention Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to a die bonder but may be applied to other types of bonding devices such as a flip chip bonder. You can. 1, the die bonder 100 of the present embodiment includes a dispenser section 110, a bonding section 120, and a circuit board 14 which extends through each of the sections 110 and 120 to carry the circuit board 14 And guide rails 13 for guiding them in the direction of the arrows. The circuit board 14 is guided by the guide rails 13 and transferred to the dispenser section 110 and is transferred to the bonding position 15 of the semiconductor die 40 on the circuit board 14 by the dispenser unit 19 The adhesive is applied. The circuit board 14 to which the adhesive is applied is conveyed along the guide rail 13 to above the bonding stage 12 of the bonding section 120. Here, the circuit board 14 is attracted and fixed on the bonding stage 12, and is heated by a heater disposed inside the bonding stage 12.

The bonding section 120 includes a bonding head 10 for operating a collet 20 which is a bonding tool and a wafer 60 which is diced in a checkerboard shape and has a finely cut rectangular semiconductor die 40 adhered to the film on the back surface And a pickup stage 50 for holding the pickup stage 50. Between the pick-up stage 50 and the bonding stage 12, a back side camera 30 for picking up the back side (bottom surface) of the semiconductor die 40 adsorbed by the collet 20 is disposed.

The die bonder 100 of the present embodiment includes an image processing section 80 for processing an image acquired by the back side camera 30 and a monitor 35 for displaying an image. The image processing unit 80 is a computer including a CPU 81, a storage unit 82, a back side camera interface 87 and a monitor interface 89 for performing information processing and calculation such as program execution, 81, the storage unit 82, the back side camera interface 87, and the monitor interface 89 are connected by a data bus 88. The back face camera interface 87 is connected to the back face camera 30 by a signal line 91. The monitor interface 89 is connected to the monitor 35 by a signal line 93, Image data acquired by the image processing section 80 to the image processing section 80 and display the image on the monitor 35. [ The storage unit 82 stores an image acquisition program 83, an image area definition program 84, a damage detection program 85 and image data 86 which will be described later.

The die bonder 100 of the present embodiment is provided with a control section 90 for controlling the operation of the dispenser unit 19 of the dispenser section 110 and the operation of the bonding head 10 of the bonding section 120 . Like the image processing unit 80, the control unit 90 is a computer including a CPU and a storage unit, and is connected to the image processing unit 80, the dispenser section 110, the bonding section 120, and the data bus 92 have.

The basic operation of the die bonder 100 of the present embodiment will be described with reference to Fig. 2 (a), the collet 20, which is a bonding tool attached to the bonding head 10 picks up the semiconductor die 40 in the pick-up stage 50. 2 (b), the collet 20 is moved by the bonding head 10 so that the semiconductor die 40 is fed to a position at which the center line 29 in the longitudinal direction is the center of the back side camera 30 do. The backside camera 30 acquires the image of the lower surface (back surface) of the semiconductor die 40 and the semiconductor die 40 is exposed to a crack Etc. are inspected for damage. The collet 20 is moved to above the bonding stage 12 by the bonding head 10 and the collet 20 is moved upward by the bonding head 10 as shown in FIG. 2 (c) The semiconductor die 40 is brought into contact with the circuit board 14 by bonding the position of the semiconductor die 40 to the bonding position 15 of the semiconductor die 40 in the circuit board 14 .

2 (d), the collet 20 has a collet body 21 made of rubber, on the surface of which a suction groove 22 for suctioning the semiconductor die 40 is mounted, and a collet body 21 A metal collet holder 23, a shaft 24 extending from the collet holder 23, and a collet shank 25 to which the shaft 24 is fixed. The collet shank 25 is attached to the bonding head 10. A hole 27 communicating with the suction groove 22 of the collet body 21 is provided in the center of the collet holder 23 and the shaft 24 and is connected to a vacuum device not shown, The die 40 sucks and fixes the semiconductor die 40 on the suction surface 26 which is the lower side of the collet body 21 in Fig. 2 (d).

The operation of detecting breakage such as cracks or defects of the semiconductor die 40 by the die bonders described with reference to Figs. 1 and 2 has been described above. In order to detect breakage, it is necessary to define a region in the acquired image or a position in the image representing the semiconductor die 40 when the semiconductor die 40 picked up on the attracting surface 26 of the collet 20 is picked up . Therefore, before actual bonding is performed, it is necessary to register the reference image using the model semiconductor die. Hereinafter, the reference image registration operation will be described with reference to Figs. 3 and 5. Fig.

As shown in step S101 in Fig. 3, the control unit 90 shown in Fig. 1 operates the bonding head 10 to move the collet 20 attached to the bonding head 10 Up stage 50, and the model semiconductor die 42 shown in Fig. 5 is adsorbed to the collet 20. The model semiconductor die 42 is a semiconductor die 40 of the same type and size as that of the actual semiconductor die 41 shown in FIG. 6 and subsequent to the actual bonding, confirming that there is no breakage such as breakage or dropout in advance. When the model semiconductor die 42 is adsorbed on the adsorption face 26 of the collet 20, for example, the model semiconductor die 42 is placed on a plate placed on the pickup stage 50, So that the model semiconductor die 42 is not damaged at the time of pick-up.

3, when the model semiconductor die 42 is sucked to the collet 20, the collet 20 is moved to the upper side of the back side camera 30 as shown in Fig. 2 (b) 5, the entire image 70 including the model semiconductor die 42, the collet body 21, and the collet holder 23 is acquired (acquired) by the back side camera 30 as shown in step S103 of Fig. do. The entire image 70 may be an image of the visual field of the back side camera 30 or an image displayed on the monitor 35. [ The collet body 21 made of rubber is obtained as a black image and the surface of the model semiconductor die 42 and the surface of the collet holder 23 which are metal planes on which light is reflected are white images . Therefore, the operator can visually determine the position and the area of the model semiconductor die 42 in the entire image 70 easily from the lightness difference in the entire image 70 as shown in Fig.

3, the operator has the same shape and size as those of the model semiconductor die 42, that is, the model semiconductor die 42 is formed on the outline of the model semiconductor die 42 in the entire image 70 displayed on the monitor 35, The reticle 74 (the frame line indicated by the one-dot chain line in Fig. 5) having the same shape as the outline shape of the design dimension of the die 42 is aligned and the area of the model semiconductor die 42 is defined on the screen of the monitor 35 (An image region delimiting step of the model semiconductor die shown in Fig. 3). Next, the operator places a rectangular reference image frame 73 on the upper left corner and the lower right corner of the model semiconductor die 42, respectively, and as shown in step S105 in FIG. 3 , The reference images 45 and 46 captured in the reference image frame 73 are registered as the upper left reference image 45 and the lower right reference image 46, respectively (reference image registration). 5, the upper left reference image 45 enters the left upper portion of the model semiconductor die 42 on the lower right side of the image, and the lower right reference image 46 includes the model semiconductor die 42 on the upper left side of the image. The lower right corner.

After the registration of the reference images 45 and 46 is completed, the die bonder 100 performs the bonding of the semiconductor die 40 according to the flowchart shown in Fig. In the following description, the actual semiconductor die 41 will be described separately from the model semiconductor die 42 used for creating the reference image. As shown in Fig. 2 (a) to Fig. 2 (b), the control unit 90 controls the wafer 60 As shown in step S202 of FIG. 4, and moves the semiconductor die 41 to a position above the back side camera 30. As shown in FIG. The image processing unit 80 executes the image acquisition program 83 and acquires the entire image 70 as shown in Fig. 6 by the back side camera 30 as shown in step S203 of Fig. 4 fair). As described above, in the entire image 70, the collet body 21 made of rubber is obtained as a black image, and the surface of the actual semiconductor die 41, which is the metal plane on which the light is reflected, The face is acquired as a white image. The image processing unit 80 executes the image region delimiting program 84 and the image processing unit 80 executes the image region delimiting program 84 so that each part of the upper left reference image 45 and the entire image 70 The brightness distribution is searched to find a place where the images in the images match. 6, the position where the boundary line 44 between the upper left corner of the semiconductor die 41 and the collet body 21 matches the image (brightness distribution) of each part of the upper left reference image 45 is set as the entire Is regarded as the position of the upper left corner of the actual semiconductor die 41 in the image 70. It is also possible to search for a place where each part of the right lower reference image 46 and the boundary line 44 in the entire image 70 match with each other and the boundary line between the right lower part of the semiconductor die 41 and the collet body 21 44) and the image of the respective portions of the right lower reference image 46 (brightness distribution) match each other is regarded as the position of the lower right corner of the actual semiconductor die 41 of the whole image 70. [ 7, the position and the area of the actual semiconductor die 41 in the entire image 70 (the area of the white actual semiconductor die 41 shown in Fig. 7) are set to be (Image area delimiting step). The area of the defined actual semiconductor die 41 is defined by the left upper corner and the lower right corner, and the size of the area is defined by the model semiconductor die 42 or the design dimension.

Next, the image processing section 80 executes the breakage detection program 85, and as shown in step S206 of FIG. 4 and FIG. 8, Is set as the inspection area (43). The inspection region 43 is located inside the contour of the actual semiconductor die 41 and is an area excluding an area of about 10 pixels from the periphery of the image area of the actual semiconductor die 41, for example.

Next, as shown in step S207 in Fig. 4, the image processing unit 80 scans the inspection area 43 shown in Fig. 9, acquires the change in brightness in the scanning direction, and stores the acquired change in brightness in the storage unit 82 . As for the scanning, for example, one pixel or several pixels are grouped as one group along the lateral direction of the actual semiconductor die 41 as indicated by an arrow line 75 shown in Fig. 9 to acquire brightness for each pixel or group. In addition, as shown by the arrow 76 shown in Fig. 9, the light is actually scanned in the longitudinal direction of the semiconductor die 41 to acquire brightness. 10, the scanning in the lateral direction of the actual semiconductor die 41 indicated by the arrow line 75 corresponds to the inspection region 43 slightly inwardly moved from the position P ₁ of the actual semiconductor die 41, one end of the point (P ₂₎ and the end point of the other terminal of the actual semiconductor die 41 where the inspection area (43) containing a little inside from (P ₅₎ of the end face on the opposite side of the performed between (P _4). The surface of the semiconductor die 41 is smooth and reflects light well. Normally, it is a white image (high brightness image), and the brightness does not change abruptly in a portion where there is no crack 48. And, as shown in the four shown in step S208, the position of Figure 10 (P ₃₎ as shown in, the scan direction brightness rapidly decreases, or as rapidly when higher or one, the change in the scanning direction of the brightness threshold value It is determined that there is a crack 48 as shown in step S209 of FIG. 4 and it is determined that a crack 48 exists in the actual semiconductor die 41 to which the collet 20 is adsorbed . 4, the image processing unit 80 outputs a signal for stopping the die bonder 100 to the control unit 90, so that the control unit 90 stops the die bonder 100. As shown in Fig.

The inspection area 43 is slightly inside of the boundary of the image area of the semiconductor die 41 as in this embodiment so that the difference in brightness in the edge of the image area is recognized as cracks or cracks The detection can be reduced and the breakage can be accurately detected.

The actual semiconductor die 41 floats a little more than the suction surface 26 of the collet 20 as shown in Fig. 11, for example, when the change in the lightness is not equal to or greater than the predetermined threshold value in step S208 of Fig. The brightness gradually changes from the position P ₆ to the position P _{4 in} FIG. 11 during the scanning of the actual semiconductor die 41 indicated by the arrow line 75 In the case where there is a slight change in the lightness in the image, the die bonder 100 is not stopped because of the breakage, and the productivity can be improved. Then, as shown in step S211 of Fig. 4, if it is determined that there is no damage to the actual semiconductor die 41 that is attracted to the collet 20, the image processing unit 80 transmits a bonding permission signal to the control unit 90 do. The control unit 90 moves the bonding head 10 and the collet 20 that receive this signal to the position above the bonding stage 12 and adjusts the position of the actual semiconductor die 41 The actual semiconductor die 41 is pushed on the circuit board 14 to perform bonding as shown in steps S213 and 2 (c) of Fig. 4 after the semiconductor die bonding position 15 of the circuit board 14 is aligned I do.

As described above, the die bonder 100 of the present embodiment can effectively prevent the broken actual semiconductor die 41 from being bonded, thereby improving the quality of the semiconductor device manufactured by the die bonder 100 Effect.

The present invention is not limited to the above-described embodiments, but includes all changes and modifications that do not depart from the technical scope and nature of the present invention, which are defined by the claims. For example, But can be applied to other types of bonding devices such as flip chip bonders.

10 ... Bonding head 12 ... Bonding stage
13 ... Guide rail 14 ... Circuit board
15 ... Bonding position 19 ... Dispenser unit
20 ... Collet 21 ... Collet body
22 ... The adsorption grooves 23 ... Collet holder
24 ... Shaft 25 ... Collet shank
26 ... Absorbing surface 27 ... hole
29 ... Center line 30 ... If the camera
35 ... Monitor 40 ... Semiconductor die
41 ... Actual semiconductor die 42 ... Model Semiconductor Die
43 ... Inspection area 44 ... boundary
45 ... Upper left reference image 46 ... Right lower reference image
48 ... Crack 50 ... Pickup stage
60 ... Wafer 70 ... Whole picture
73 ... Reference image frame 74 ... Reticle
80 ... The image processing unit 81 ... CPU
82 ... The storage unit 83 ... The image acquisition program
84 ... Image area separation program 85 ... Breakage detection program
86 ... Image data 87 ... If the camera interface
88, 92 ... Data bus 89 ... Monitor interface
90 ... Control sections 91, 93 ... Signal line
100 ... Die bonder 110 ... Dispenser section
120 ... Bonding section

Claims

As a bonding apparatus,
A pickup stage for holding a wafer including a semiconductor die,
A bonding stage for holding a substrate on which the semiconductor die is mounted,
Up stage to the bonding stage, the entire image including the image of the semiconductor die sucked to the collet and the image of the adsorption face of the collet that adsorbs the semiconductor die, A camera which acquires a plurality of reference images including a part of the surface and each part of the semiconductor die, the reference image being smaller in area than the entire image; And
An image processing unit for processing each image acquired by the camera;
And,
Wherein the image processing unit comprises:
Comparing the brightness distribution of the whole image with the brightness distribution of the plurality of reference images to specify a boundary of the entire image corresponding to each of the respective angles, Image area delimiting means for delimiting an outer side of a region corresponding to the semiconductor die in the entire image from the inspection region; And
A damage detection means for scanning within the inspection region and judging that the semiconductor die is broken when the rate of change of brightness in the scanning direction is equal to or larger than a predetermined threshold value;
To have,
Wherein the breakage detecting means is set as an inspection region inside the image region of the semiconductor die defined by the image region delimiting means and is scanned in the inspection region, And judges whether or not the semiconductor die is broken until the semiconductor die is mounted on the semiconductor die.

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A method of detecting breakage of a semiconductor die by a bonding apparatus having a pick-up stage for holding a wafer including a semiconductor die and a bonding stage for holding the substrate on which the semiconductor die is mounted,
A reference image acquiring step of acquiring a plurality of reference images including the attracting surface and each part of the semiconductor die by dividing and imaging the back surface of the semiconductor die adsorbed on the attracting surface of the collet into a plurality of regions;
The semiconductor die is picked up from the pick-up stage to the bonding stage, and an entire image including an image of the semiconductor die sucked to the collet and an attracting surface image of the collet that attracts the semiconductor die is obtained A whole image acquiring step;
The brightness distribution of the whole image is compared with the brightness distribution of the plurality of reference images to specify the boundary of the entire image corresponding to each part of the semiconductor die to inspect the area corresponding to the semiconductor die in the whole image An image area delimiting step of delimiting the outside of the area corresponding to the semiconductor die in the entire image from the inspection area; And
A damage detection step of the semiconductor die which scans the inspection area and judges that the semiconductor die is damaged when the rate of change of brightness in the scanning direction is equal to or larger than a predetermined threshold value;
To have,
Wherein the breakage detecting step includes setting an inspection area inside the image area of the semiconductor die defined by the image area demarcining step, scanning the inspection area, and causing the semiconductor die to move to the substrate And judging whether or not the semiconductor die is damaged before mounting the semiconductor die.

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