JP2002190494A - Apparatus for bonding data setting and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide stable peeling strength between a wire and a bonding pad, and to improve the reliability of a product. SOLUTION: In order to reduce the area superimposed by a probe mark 50 and a joined surface (equivalent to a joined surface mark 60) of the wire and the pads P01-P07 and to increase area, excluding a part superimposed with the probe mark 50 in the joined surface, an offset amount from the center point of the pads P01-P07 is set. Bonding can be performed as to avoid the probe mark 50, and as a result the decline in the peeling strength due to the probe mark 50 is prevented, and the reliability of the product is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding data setting apparatus, and more particularly to an apparatus for setting an actual bonding point of a wire to bond the wire to a bonding pad.

[0002]

2. Description of the Related Art In a wire bonding apparatus, a wire such as a gold wire is bonded to a bonding pad made of aluminum or the like on a semiconductor device.
Prior to this bonding operation, the supplied semiconductor device is imaged, the obtained image data is subjected to image processing such as pattern matching, the shape of the bonding pad is recognized, and the center point of the bonding pad is obtained. The point is set as the actual bonding point. And
Bond the wire to the set actual bonding point.

[0003] In this bonding operation, a wire having a ball formed at an end thereof by an electric torch or the like is held by a capillary, and while applying a weight to the capillary in a direction facing the bonding pad, ultrasonic vibration is applied to the wire.
This is performed by destroying the Al oxide film at the Au boundary to form a eutectic layer and joining.

[0004]

However, there is a certain limit in the peeling strength between a wire bonded by a conventional method and a bonding pad, and this is a major problem particularly in achieving a fine pitch. I have. The applicant has conducted a detailed inspection of the interface between the wire and the bonding pad. As a result, the contact of the probe to the bonding pad in the inspection process of the semiconductor chip before the wire bonding adversely affects the peeling strength. I learned what was given. That is, the probe comes into contact with the bonding pad in the inspection step, and at this time, a fine probe mark (probe mark) remains on the surface of the bonding pad as a concave portion. For this reason,
If the center point of the bonding pad is set as the actual bonding point, a part of the bonding surface between the wire and the bonding pad overlaps with the probe mark, so that a sufficient eutectic layer is not formed in the probe mark. As a result, the peeling strength of both becomes weak.

An object of the present invention is to provide a means for obtaining a stable peeling strength between a wire and a bonding pad and improving the reliability of a product.

[0006]

According to a first aspect of the present invention, there is provided a bonding data setting apparatus for setting an actual bonding point of a wire in order to bond the wire to the bonding pad. Pad detecting means for detecting a position of a point, offset amount obtaining means for obtaining an offset amount from a center point of the bonding pad, and offset direction obtaining means for obtaining an offset direction of an actual bonding point with respect to the center point of the bonding pad And an arithmetic processing means for setting an actual bonding point at a position shifted by the offset amount in the offset direction with respect to the center point based on the position of the reference point, the offset amount and the offset direction. It is a bonding data setting device.

In the first aspect of the present invention, the pad detecting means detects the position of a predetermined reference point on the bonding pad. The offset amount obtaining means obtains an offset amount from the bonding pad center point. The offset direction obtaining means obtains an offset direction of an actual bonding point with respect to the bonding pad. The arithmetic processing means sets an actual bonding point at a position shifted by the offset amount in the offset direction with respect to the center point based on the position of the reference point, the offset amount, and the offset direction. Here, the offset amount is a distance from the center point, and the offset direction is a direction with respect to the center point.

According to the first aspect of the present invention, by providing an appropriate offset amount and offset direction, a probe or the like attached to the bonding pad can be compared with a case where the center point of the bonding pad is the actual bonding point. The actual bonding point can be set so that the area of overlap between the indentation and the bonding surface between the wire and the bonding pad is reduced, and the area of the bonding surface excluding the portion overlapping with the indentation is increased. This can prevent a decrease in peel strength due to an indentation of a probe or the like, and can improve product reliability.

A second aspect of the present invention is the bonding data setting apparatus according to the first aspect of the present invention, wherein the reference point is a center point of the bonding pad.

According to the second aspect of the present invention, the center point of the bonding pad can be used as both a reference for specifying the position of the bonding pad and a reference for setting the offset amount and the offset direction.

According to a third aspect of the present invention, in the bonding data setting apparatus according to the first or second aspect of the present invention, the arithmetic processing means uses a single offset amount to execute actual operations on a plurality of bonding pads. A bonding data setting device for setting a bonding point.

According to the third aspect of the present invention, since a single offset amount can be used for setting actual bonding points for a plurality of bonding pads, an input operation in which the offset amounts for a plurality of bonding pads are duplicated is eliminated. Can be simplified.

A fourth aspect of the present invention is the bonding data setting device according to any one of the first to third aspects of the present invention, wherein the arithmetic processing means comprises a plurality of bonding pads using a single offset direction. The bonding data setting device is characterized in that an actual bonding point for is set.

In the fourth aspect of the present invention, since a single offset direction can be used for setting actual bonding points for a plurality of bonding pads, redundant input operations in the offset directions for a plurality of bonding pads are eliminated. Can be simplified.

According to a fifth aspect of the present invention, there is provided a bonding data setting device for setting an actual bonding point of a wire in order to bond the wire to the bonding pad, wherein a position of a predetermined reference point of the bonding pad is detected. Pad detecting means, indentation detecting means for detecting the position of a predetermined reference point of an indentation such as a probe attached to the bonding pad, and based on the position of the reference point of the bonding pad and the position of the reference point of the indentation As compared with the case where the center point of the bonding pad is set as the actual bonding point, the overlap area between the indentation and the bonding surface between the wire and the bonding pad is reduced, and the indentation of the bonding surface overlaps with the indentation. The offset amount and offset from the center point of the bonding pad are increased so that the area excluding the portion to be bonded increases. Offset setting means for setting a winding direction, a bonding data setting device and a processing means for setting the actual bonding points on the basis of said offset amount and offset direction with the position of the reference point of the bonding pad.

In the fifth aspect of the present invention, the pad detecting means detects the position of a predetermined reference point of the bonding pad. The indentation detecting means detects the position of a predetermined reference point of the indentation. And the offset input means, compared with the case where the center point of the bonding pad is the actual bonding point,
The amount of offset from the center point of the bonding pad and the amount of overlap between the bonding surface of the bonding pad and the wire are reduced, and the area of the bonding surface excluding the portion overlapping the indentation is increased. Set the offset direction. Therefore, according to the fifth aspect of the present invention, the same effect as that of the first aspect of the present invention can be obtained. In addition, since the position of the indentation is detected and the actual bonding point is set based on this position, the setting input operation can be performed. It can be further simplified.

According to a sixth aspect of the present invention, there is provided a bonding data setting method for setting an actual bonding point of the wire in order to bond the wire to the bonding pad, the method comprising detecting a position of a predetermined reference point on the bonding pad. Obtaining an offset amount from the center point of the bonding pad, obtaining an offset direction of an actual bonding point with respect to the center point of the bonding pad,
A bonding data setting method, comprising: setting an actual bonding point at a position shifted by the offset amount in the offset direction with respect to the center point based on the position of the reference point, the offset amount, and the offset direction. is there. According to the sixth aspect of the invention, the same effect as that of the first aspect of the invention can be obtained.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a wire bonder according to an embodiment of the present invention. In FIG. 1, a bonding arm 3 is provided on a bonding head 2 mounted on an XY table 1, and the bonding arm 3 is driven by a Z-axis motor 16 in a vertical direction. A tool 4 is attached to the tip of the bonding arm 3.
Has a wire inserted therethrough. The tool 4 in the present embodiment is a capillary.

A camera arm 6 is also fixed to the bonding head 2, and a television camera 7 is fixed to the camera arm 6. The television camera 7 images the semiconductor device 14. The XY table 1 is configured so that it can be accurately moved in the X direction and the Y direction, which are coordinate axis directions orthogonal to each other in the horizontal direction, by an XY table motor 12 installed near the XY table 1 and including two pulse motors and the like. ing. The above is a known structure.

The XY table 1 stores a motor drive unit 30 according to a command from a control unit 34 such as a microprocessor.
And an XY table motor 12.
The image data obtained by the imaging of the TV camera 7 is
It is converted into an electric signal and processed by the image processing unit 38,
The data is input to the arithmetic processing unit 37 via the control unit 34. The arithmetic processing unit 37 executes various arithmetic operations described later, and the control memory 35 temporarily stores programs for such arithmetic operations and other operation programs of the system. The manual input unit 33 and the television monitor 39 are connected to the control unit 34.

The manual input means 33 is preferably a pointing device such as a mouse input device having at least an XY direction indicating function and a set signal input function, and a keyboard having a character input function. The television monitor 39 is composed of a CRT or a liquid crystal display device, and its display screen 20 displays an image of the semiconductor device 14 (see FIG. 3) or a numerical value setting image (see FIG. 4) captured by the television camera 7. It is displayed based on an operation input by an operator or an output of the control unit 34. The arrow-shaped pointer 40 displayed on the display screen 20 is configured to move in conjunction with the operation of the manual input unit 33.

The data memory 36 stores past setting data such as the offset amount, the shape of the joint surface of the ball, the shape of the indentation, and the like, and a data library storing default values which are initial states of the wire bonding apparatus. .

Next, the operation in the setting mode of the present embodiment will be described with reference to FIGS. First, an image of the semiconductor device 14 captured by the television camera 7 is displayed on the display screen 20 (S102).

Next, it is determined whether or not a pad instruction has been input on the display screen 20 by the operator (S1).
04). This pad instruction input allows the operator to select one of the bonding pads (hereinafter referred to as “pad P” in the image of the semiconductor device 14 on the display screen 20; the pads P are indicated by reference numerals P01 to P07 in the drawing). , By the manual input means 33. For example, the manual input unit 3 is provided at an arbitrary part of the area corresponding to the pad P.
3. Pointer 40 is overlaid by a pointing device such as a mouse input device 3 and the set button is pressed (hereinafter, moving the pointer 40 on the display screen 20 to generate an action is referred to as "clicking"). ).

For example, when a pad instruction input for the pad P01 is performed, it is determined as a next step whether an offset direction setting input has been performed for the specified pad P01 (S106). This offset direction setting input is made on the display screen 2 by an appropriate display switching input.
In the numerical value setting image displayed at 0 (see FIG. 4), in the case of the pad P01, the operator selects a vertical column “000” and a leftmost column “1” (pad P0).
01)) at the intersection of the rows
This is performed by clicking on any of the characters X, "+ Y", "-X", and "-Y" or by inputting a cursor designation.
The layout of the display screen 20 is an example, and is not limited to this.

The operator sets the center point of the pad P in the image of the semiconductor device 14 on the display screen 20 while observing the position of the probe mark 50 which is a recess formed by the contact of the probe in the inspection process. As compared to the case where the actual bonding point is set, the probe mark 50
And the overlapping area of the bonding surface of the wire ball and the pad P (indicated by the bonding surface mark 60) is reduced, and the area of the bonding surface excluding the portion overlapping the probe mark 50 is increased. Set. That is, the offset direction is selected and set so that the bonding surface is formed avoiding the probe mark 50.

The "+ X", "+ Y", "-X", "-Y"
Indicates an offset amount. The offset amount in the present embodiment is a distance in the X or Y direction from the center point of each pad P on the center lines A and B in FIG. 3, and a default value of, for example, 4 micrometers is set. However, any value can be set by manual input by the operator.

If an offset direction setting input is made, a joining surface mark 60 is displayed next at a position offset from the center point of each pad P by the set offset amount. (The state of FIG. 3).

If the determination in step S106 is negative, that is, if there is no offset direction setting input for the designated pad P, an appropriate input request message such as "Do you want to set the offset amount to 0?" (S116), the operator sets the offset amount to 0,
In other words, if it is input that bonding is to be performed at the center point of the pad P, the process proceeds to step S108, and the bonding surface mark 60 is displayed at the center point of the pad P.

This offset direction setting input is repeated until the setting input for all the pads P is completed (S110), and the operator inputs an end message (for example, in response to an input request of "Do you want to end?"). "Yes"
Is input), the offset amount “0” is set for the unset pad P (S112), the setting is stored in the data memory 36 (S114), and this routine ends. Note that, instead of the configuration in which the offset amount “0” is set for all the unset pads P in step S112 as in the present embodiment, an offset amount “0” is initially provided as a default value for all the pads P. In advance, the offset amount may be set as the setting input only for the pad P for which the offset direction setting input has been made.

Thereafter, in the present apparatus, an actual bonding operation for the same type of semiconductor device 14 is performed by the tool 4, and based on the offset amount and the offset direction for each pad P set in the routine relating to the above setting, Bonding is performed at a position offset from the center point of P. Thereby, the bonding is performed so that the bonding surface is formed avoiding the probe mark 50.

As described above, in the present embodiment, the offset direction between the probe mark 50 and the bonding surface between the ball of the wire and the pad P is set in the offset direction as compared with the case where the center point of the pad P is set as the actual bonding point. The setting is made so that the overlapping area decreases and the area of the joining surface excluding the portion overlapping the probe mark 50 increases. Then, an actual bonding point is set based on the input offset direction and offset amount. Therefore, in the present embodiment, bonding can be performed so as to avoid the probe mark 50, whereby a decrease in the peeling strength due to the probe mark 50 can be prevented, and the reliability of the product can be improved.

In this embodiment, the offset amount is set to a single (uniform) value, and the offset direction for each pad P is set and inputted, so that actual bonding points for a plurality of pads P are set. Therefore, there is no need to input the offset amount individually for each pad P,
The work of setting the actual bonding point can be remarkably streamlined. However, instead of a configuration in which the offset amount is uniform, a configuration may be used in which the offset amount can be individually set to different values for each of the positive and negative values in the X direction and the Y direction, and a plurality of candidate values of the offset amount are displayed. The operator may select and input one of them.

In this embodiment, since the offset amount is set with reference to the center point of the pad P,
There is an advantage that the center point of the pad P can be used for both a reference for specifying the position of the pad P and a reference for setting the offset amount and the offset direction. The setting of the offset amount and the offset bonding work may be performed using an arbitrary point in P, for example, an outer edge or vertex as a reference point.

In the present embodiment, the offset direction is individually input for each pad P. Instead of this configuration, the acquisition of the offset direction for a plurality of pads P is performed by a single input of the offset direction. A configuration realized by the operation, for example, a plurality of pads P arranged on one side of the semiconductor chip 14 is extracted by image processing, and on the condition that an offset direction is input for one of the pads P, The same offset direction may be set for all other pads P.

In this embodiment, the probe mark 5
Although the position of 0 is visually confirmed by the operator, and the offset direction is selected and input according to the visual confirmation, the position of the probe mark 50 on each pad P is detected by image processing instead of this configuration. In accordance with the position of the detected probe mark 50, the probe mark 50 is compared with the case where the center point of the pad P is set as the actual bonding point.
In such a manner that the overlapping area of the bonding surface between the wire ball and the pad P decreases and the area of the bonding surface excluding the portion overlapping the probe mark 50 increases, that is, in the direction to avoid the probe mark 50. The configuration may be such that the actual bonding point is automatically set by shifting. According to this configuration, the setting operation of the actual bonding point can be significantly simplified.

In this embodiment, the actual bonding point is offset by a preset offset amount. However, instead of this configuration, the probe mark 50 on each pad P detected by image processing is replaced.
The actual bonding point may be calculated and set individually for each pad P so that the probe mark 50 and the bonding surface between the wire and the pad P do not overlap each other in accordance with the position. In this case, it is preferable to restrict the range of the position of the actual bonding point to be set so that the bonding surface between the wire and the pad P does not protrude from the outer edge of the pad P. FIG. 3 shows an example in which the actual bonding point can be set so that the overlapping area between the probe mark 50 and the bonding surface between the wire ball and the pad P is eliminated. It is not indispensable that it disappears. If the overlapping area between the probe mark 50 and the bonding surface between the ball of the wire and the pad P decreases and the area of the bonding surface excluding the portion overlapping the probe mark 50 increases. Sufficient, thereby achieving the intended purpose.

Further, the area where the bonding surface between the wire and the pad P protrudes from the outer edge of the pad P, the known peeling strength per unit area between the semiconductor device 14 and the wire ball outside the pad P, and the area of the probe mark 50 The actual bonding point may be calculated and set so that the peeling strength of the wire is maximized based on the known peeling strength per unit area between the probe mark 50 and the wire ball.

Further, in the present embodiment, the example in which the present invention is applied to the setting of the actual bonding point between the wire ball and the pad P has been described. However, when the bonding between the wire and the pad P is performed without using the wire ball. The present invention can be applied to setting of actual bonding points, and such a configuration also belongs to the category of the present invention.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a bonding apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an example of an actual bonding point setting process according to the embodiment.

FIG. 3 is a display example of a display screen of a television monitor, and is an explanatory diagram showing an image of a semiconductor device.

FIG. 4 is a display example of a display screen of a television monitor, and is an explanatory diagram showing a numerical value setting image.

[Explanation of symbols]

1 XY table, 2 bonding head, 4 tools, 7 television camera, 14 semiconductor chip, 20 display screen, 33 manual input means, 34 control section, 36 data memory, 37 arithmetic processing section, 38 image processing section, 3
9 TV monitor, 40 pointer, 50 probe mark, 60 joint surface mark, P01, P02, P03,
P04, P05, P06, P07 Bonding pad (pad).

Claims (6)

[Claims] 1. A bonding data setting device for setting an actual bonding point of a wire in order to bond the wire to the bonding pad, comprising: pad detecting means for detecting a position of a predetermined reference point on the bonding pad; Offset amount obtaining means for obtaining an offset amount from a center point of the bonding pad; offset direction obtaining means for obtaining an offset direction of an actual bonding point with respect to the center point of the bonding pad; position of the reference point; and the offset amount And a processing means for setting an actual bonding point at a position shifted by the offset amount in the offset direction with respect to the center point based on the offset direction. 2. The bonding data setting device according to claim 1, wherein the reference point is a center point of the bonding pad. 3. The bonding data setting device according to claim 1, wherein the arithmetic processing means sets actual bonding points for a plurality of bonding pads using a single offset amount. A bonding data setting device. 4. The bonding data setting device according to claim 1, wherein the arithmetic processing unit determines actual bonding points for a plurality of bonding pads using a single offset direction. A bonding data setting device for setting. 5. A bonding data setting device for setting an actual bonding point of the wire in order to bond the wire to the bonding pad, wherein the pad detecting means detects a position of a predetermined reference point of the bonding pad. Indentation detecting means for detecting the position of a predetermined reference point of an indentation such as a probe attached to the bonding pad; and, based on the position of the reference point of the bonding pad and the position of the reference point of the indentation, Compared with the case where the center point was set as the actual bonding point, the overlapping area of the indentation and the bonding surface between the wire and the bonding pad was reduced, and the portion of the bonding surface overlapping the indentation was removed. Offset amount setting for setting an offset amount from the center point of the bonding pad so as to increase the area Means for setting an actual bonding point based on the position of the reference point of the bonding pad and the offset amount. 6. A bonding data setting method for setting an actual bonding point of a wire for bonding a wire to the bonding pad, the method comprising: detecting a position of a predetermined reference point on the bonding pad; Obtain the offset amount from the center point, obtain the offset direction of the actual bonding point with respect to the center point of the bonding pad, and, based on the position of the reference point, the offset amount and the offset direction, A bonding data setting method, wherein an actual bonding point is set at a position shifted by the offset amount in the offset direction.