JPH1027801A - Bump cutting device, bump bonding device and bonding of bump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity of a non-defective IC by executing automatically removal of defective stud bumps and rebonding of stud bumps by a method wherein a bump cutting device is provided with a cutting member, which cuts the stud bumps along electrode pads by ultrasonic vibrations, and ultrasonic oscillation units, which impart ultrasonic vibration to the cutting member. SOLUTION: A bump cutting device is provided with a cutting member 19 and ultrasonic oscillation units 7 and 8. The member 19 consists of a blade member 191 and a mounting member 192 and cuts stud bumps formed on electrode pads on a semiconductor chip by ultrasonic vibration along the electrode pads. The units 7 and 8 transmit ultrasonic waves, which are generated from the ultrasonic oscillators 8, to the cutting member 19 via the ultrasonic horns 7. The member 19 generates the ultrasonic waves in the directions shown by arrows 61. Thereby, the cutting of the stud bumps is facilitated and the cutting can be conducted without damaging the element. As a result, an IC of a stable quality can be produced and the enhancement of the productivity of the IC can be contrived.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bump cutting apparatus for cutting a stud bump formed on an electrode pad of a semiconductor element using a wire bonding technique when the bump is defective, and a bump provided with the bump cutting apparatus. The present invention relates to a bonding apparatus and a bump bonding method.

[0002]

2. Description of the Related Art Conventionally, a stud bump bonding technique in which a gold bump is ultrasonically bonded to an electrode pad portion of a flip chip IC by applying an IC (semiconductor integrated circuit) -related wire bonding technique is known. This will be described below with reference to FIGS. FIG. 8 shows an example of a commonly used bump bonding apparatus. 1 is a capillary movable in the vertical and horizontal directions in the figure, 2 is a gold wire inserted into this capillary,
Reference numeral 4 denotes a semiconductor element, and reference numeral 5 denotes a spark generator, which is arranged near the tip of the gold wire 2 protruding from the capillary 1.
6 is a clamper for the gold wire 2, 7 is an ultrasonic horn having a capillary 1 attached to its tip, 8 is an ultrasonic oscillator that oscillates ultrasonic waves to the ultrasonic horn 7, 9 is the ultrasonic horn 7 and the ultrasonic wave A head up / down driving mechanism for driving a head portion having an oscillator 8 up and down, an XY table 10 on which the head portion and the head up / down driving mechanism 9 are mounted and which can be moved in X and Y directions, 11 is an air tensioner, 12
Denotes a heat stage, 13 denotes a heater, 14 denotes a position confirmation camera device for confirming the position of the semiconductor element 4, and 15 denotes a monitor image receiver.

[0003] The operation of the bump bonding apparatus having the above configuration will be described. First, the position camera device 14
The electrode pad 64 on the semiconductor element 4 is imaged, and the arrangement position of the electrode pad 64 is confirmed by the monitor receiver 15. Then, as shown in FIG. 9A, a spark is applied from a spark generator 5 to the tip of the gold wire 2 inserted into the capillary 1, and the gold wire 2 is melted to form a gold ball 2b. Next, as shown in FIG. 2B, the capillary 1 is lowered toward the semiconductor element 4 and the gold ball 2b is brought into contact with a predetermined electrode pad 64 of the semiconductor element 4. At the time of the contact, the capillary 1 is further lowered slightly to the lower end position 63 so that a predetermined load is applied to the gold ball 2b, and ultrasonic waves are transmitted from the ultrasonic oscillator 8 to the ultrasonic horn 7.
Acting on the capillary 1 via the, the capillary 1 is ultrasonically vibrated in the direction of the arrow 62. Therefore, the gold ball 2 b is joined to the electrode pad 64 of the semiconductor element 4 while being formed into the shape of the bump pedestal 3 by the capillary 1. Next, after raising the capillary 1 as shown in FIG. 3C, the capillary 1 is slightly shifted in the horizontal direction as shown in FIG. The capillary 1 is lowered again so as to be sandwiched and pressed between the tip end portion 1a of the capillary 1 and the outer peripheral portion 3b of the bump base 3. Thus, the shape of the stud bump 3a is formed. The portion 2a, which is a press-contact portion of the gold wire 2 due to the press-contact operation, receives damage such as a decrease in wire diameter. Next, as shown in FIG. 5E, the capillary 1 is raised by a predetermined amount, the gold wire 2 is clamped by the clamper 6, and the capillary 1 is further raised as shown in FIG.
Pull the gold wire 2 upward. In this way, a portion 2a of the gold wire 2 damaged by the pressing operation in FIG. 9D, that is, a portion sandwiched between the leading edge 1a of the capillary 1 and the outer peripheral portion 3b of the bump pedestal 3. The gold wire 2 is torn, and the stud bump 3a is completed.

[0004]

However, when the stud bump 3a is formed by the above-described operation, the size of the bump 3a due to dirt, scratches or other disturbance on the surface of the semiconductor element 4, the bump 3a Often, abnormalities in the shape of the convex portions and the like occur. If these abnormal situations are overlooked, a defective IC is naturally produced, resulting in a product failure in a later process, resulting in a large loss. Therefore, the operator visually judges the quality of all the shapes of the formed stud bumps 3a. Also, more expensive I
C is increasing, and in order to suppress the loss cost, when a defective bump is found, the defective bump is removed with a bamboo-like material, and repair is performed by forming a stud bump again at the same position. ing. Therefore, cost and time loss for the inspection worker are generated.
Further, since the number of times of handling the semiconductor element 4 increases, the semiconductor element 4 may be broken. The present invention has been made to solve such a problem, and a bump cutting device capable of improving the productivity of non-defective ICs by automatically performing defective bump removal and bump rebonding. It is an object to provide a bump bonding apparatus provided with the bump cutting apparatus and a bump bonding method using the bump bonding apparatus.

[0005]

According to a first aspect of the present invention, there is provided a bump cutting apparatus, wherein a stud bump formed on an electrode pad of a semiconductor element is connected to the electrode pad near the electrode pad by ultrasonic vibration. A cutting member for cutting along;
An ultrasonic oscillator for applying the ultrasonic vibration to the cutting member.

According to a second aspect of the present invention, there is provided a bump bonding apparatus having a bump forming apparatus for forming a stud bump on an electrode pad formed on a semiconductor element. When the formed stud bump is defective, a cutting member for cutting the defective stud bump along the electrode pad near the electrode pad by ultrasonic vibration, and applying the ultrasonic vibration to the cutting member. A bump cutting device having an ultrasonic oscillation device is provided.

Further, according to a third aspect of the present invention, there is provided a bump bonding method for forming a stud bump on an electrode pad of a semiconductor element, and determining whether the stud bump formed in the bump forming step is good. And a cutting step of cutting the defective stud bump along the electrode pad in the vicinity of the electrode pad by a cutting member that ultrasonically vibrates when the inspection step determines that the stud bump is defective. And characterized in that:

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A bump cutting apparatus according to an embodiment of the present invention, a bump bonding apparatus having the bump cutting apparatus, and a bump bonding method executed by the bump bonding apparatus will be described with reference to the drawings. This will be described below. In each of the drawings, the same reference numerals are given to components that perform the same or similar functions. Further, an embodiment corresponding to an ultrasonic oscillator corresponds to an ultrasonic oscillator 8 and an ultrasonic horn 7 provided in a bump cutting device 18 described later. First, the bump bonding apparatus 101 will be described. As shown in FIG. 1, the bump bonding apparatus 101 includes a bump forming apparatus 16, an inspection apparatus 17, a bump cutting apparatus 18, and a control apparatus 51. Further, at least the bump forming device 16, the inspection device 17, and the bump cutting device 18 are mounted on the same XY table 10 that can move in the X and Y directions. On the other hand, as shown in FIG. 8, the semiconductor element 4 in which the stud bump 3a is formed on the electrode pad 64 by the bump forming device 16 is
It is placed on the heat stage 12 with the circuit formation surface on which the electrode pad 64 is formed facing up.

The bump forming apparatus 16 has the same configuration and performs the same operation as the conventional bump forming apparatus shown in FIG. 8, so that the detailed description will be omitted. That is, the bump forming device 16 includes the capillary 1, the spark generator 5, the clamper 6, the ultrasonic horn 7, the ultrasonic oscillator 8, the head vertical drive mechanism 9, and the air tensioner that project the gold wire 2 from the tip 1a. Then, stud bumps are formed on the electrode pads 64 of the semiconductor element 4 using a wire bonding technique based on the operation shown in FIG.

The inspection device 17 is disclosed in Japanese Patent Application No. 6-187414.
7, a camera device 171, an illumination device 172, and a monitor receiver 17 as shown in FIG.
3 is provided. Such an inspection device 17 performs the following operation. That is, after arranging the camera device 171 right above the stud bump 3a formed on the electrode pad 64 of the semiconductor element 4, the illumination device 172 emits light to the stud bump 3a, and reflects the reflected light from the stud bump 3a. Camera device 1
An image is taken at 71. As shown in FIG. 7, since the portion other than the stud bump 3a is a plane, the intensity of the reflected light L1 from this portion is large, while the intensity of the reflected light L2 at the stud bump 3a is large because the stud bump 3a is not a plane. Is small. The image of the stud bump 3a obtained by the intensity of the reflected light is displayed on the monitor receiver 1
73, a visual indication is given, and the electrode pad 64 of the semiconductor element 4 is displayed.
It is determined whether or not the stud bump 3a has been formed normally. Note that the determination is made by the operator using the monitor receiver 1.
The inspection may be performed by watching the image of 73, or may be automatically performed by an inspection apparatus using an image processing technique. Further, by disposing the camera device 171 right above the stud bump 3a to be inspected, coordinate position information in the X and Y directions on the stud bump 3a to be inspected can be obtained. Is sent to the control device 51 from the controller.

As shown in a side view of FIG. 2, the bump cutting device 18 has substantially the same configuration as the bump forming device shown in FIG. 8, that is, the bump forming device 17 in the above-described embodiment. In the bump cutting device 18, a cutting member 19 is attached to the tip of the ultrasonic horn 7 instead of the capillary 1 provided in the bump forming device 17. In addition, due to the function of the bump cutting device 18, the bump cutting device 18 does not need to be provided with the gold wire 2, the clamper 6, and the air tensioner. The cutting member 19 includes a blade member 191 and a mounting member 192. The blade member 191 is provided at one end of the mounting member 192, and the other end is detachably attached to the distal end portion of the ultrasonic horn 7 by a fixing member 193. Can be
In each of the drawings, the blade member 191 is exaggerated in comparison with other members. The blade member 191 has, for example, a rectangular planar shape as shown in FIG. 3, and the length of one side of the tip portion 191a that abuts on the stud bump 3a and cuts the stud bump 3a is equal to that of the stud bump 3a.
Is appropriately selected in accordance with the size of. Also, the blade member 191
Is made of a metal that has been subjected to a superhard treatment in the present embodiment, but may be made of another material, for example, a material such as ceramic. To the cutting member 19, an ultrasonic wave of about 50 KHz to 200 KHz generated by an ultrasonic oscillator 8 constituted by a piezoelectric element, for example, a piezo element, is transmitted via the ultrasonic horn 7, and the cutting member 19 Arrow 6
Ultrasonic vibration occurs in the direction indicated by 1. The ultrasonic horn 7
Are configured to efficiently transmit the energy of the ultrasonic vibration generated by the ultrasonic oscillator 8 to the cutting member 19.

In order to remove the cut stud bumps 3a from the semiconductor element 4, the suction port 20 is disposed near the cutting member 19 or is movable near the cutting member 19.
It is preferable that the bump bonding apparatus 101 be provided with a removing device 20 having a and removing the cut stud bump 3a from the semiconductor element 4 by a suction operation.

The stud bumps 3a are generally formed along four sides of the rectangular semiconductor element 4. On the other hand, the vibration direction of the cutting member 19 is determined by the installation direction of the ultrasonic oscillator 8, and is limited to one direction as described above. Therefore, in the cutting member 19 that can be cut only with the tip portion 191a as shown in FIG. 3, the installation direction of the ultrasonic oscillator 8 is changed, or the semiconductor element 4 and the bump cutting device 18 are relatively moved. As long as the semiconductor element 4 is not rotated by, for example, 90 degrees, only the stud bumps 3a formed on two opposing sides of the four sides of the rectangular semiconductor element 4 can be cut. Therefore, for example, as shown in FIG. 4, the installation direction of the ultrasonic oscillator 8 is changed by providing a blade member 192 having a tip portion 191 a at at least one end in each of two directions orthogonal to each other in a cross shape. Or the rotation of the semiconductor element can be performed without performing the relative rotation.
The cutting operation can be performed on the stud bump 3a formed on the side.

The bump cutting device 18 controls the cutting operation from the electrode pad 64 on the semiconductor element 4 for the stud bump 3a determined to be defective by the inspection device 17 by the control device 51. Run while being.
The details of the cutting operation will be described later. In the bump bonding apparatus 101, the stud bump 3
On the electrode pad 64 from which a has been removed, the stud bump 3a is formed again by the bump forming device 16 under the control of the control device 51.

The operation of the thus configured bump bonding apparatus 101 will be described. The semiconductor element 4
A pre-process that is generally performed to form the stud bumps 3a on the electrode pads 64 of FIG.
A description of steps for mounting the semiconductor element 4 on the semiconductor device 2 and recognizing the position of the mounted semiconductor element 4 will be omitted. In step 1 (indicated by “S” in the figure) 1 shown in FIG.
As described above, the stud bump 3a is formed on the electrode pad 64 of the semiconductor element 4 by the operation of the bump forming device 16. Also, as shown in FIG.
In order to form the bump pedestal 3, the capillary 1 descends to the descending end position 63.
Obtains the height information of the descending end position 63. The height information is sent from the bump forming device 16 to the control device 51. In FIG. 5A, the height of the bump pedestal 3 indicated by “I” is generally 20 to 25 μm.
The length of one side of the electrode pad 64 indicated by “II” is 100 μm in the present embodiment.

In step 2, as described above, information on the shape of the stud bump 3a is obtained based on the intensity of the reflected light. In this embodiment, the quality of the stud bump 3a is automatically determined by the inspection device 17. Also, by moving the camera device 171 of the inspection device 17 right above the stud bump 3a to be inspected,
The position information of the X and Y coordinates of the stud bump 3a to be inspected is supplied from the inspection device 17 to the control device 51. In step 2, the formed stud bump 3
If a is determined to be good, the next stud bump 3
The process moves to the inspection of a. On the other hand, when it is determined that the formed stud bump 3a is defective, the process proceeds to a bump removing step of Step 3.

In step 3, the stud bump 3 a determined to be defective is cut by the bump cutting device 18, and the cut stud bump 3 a is removed by the removing device 20. In the cutting operation of the stud bump 3a, in order not to damage the electrode pad 64,
The cutting of the stud bump 3a is performed so as to form a remaining bump 131 having a thickness III on the electrode pad 64, as shown in FIG. In the present embodiment, the thickness dimension III is about 5 μm. In step 3, first, the control device 51 controls the amount of movement of the XY table 10 based on the position information of the X and Y coordinates of the stud bump 3 a supplied to the control device 51 in step 2, and is determined to be defective. The cutting member 19 of the bump cutting device 18 is arranged at the position of the electrode pad 64 where the stud bump 3a is formed. Next, as described above, the thickness dimension II
In order to form the remaining bump 131 having I, the control device 51 transmits the height information of the lower end position 63 supplied to the control device 51 in step 1 and the height dimension I of the bump base 3 which is known in advance. , And the known amount of thickness of the electrode pad 64, the amount of descent of the cutting member 19 is calculated.
Based on the calculation result, the control device 51 controls the driving of the vertical drive mechanism 9 of the bump cutting device 18, and
At the remaining bump upper surface position 65.

Next, as shown in FIG. 5B, the ultrasonic oscillator 8 of the bump cutting device 18 oscillates an ultrasonic wave under the control of the control device 51, and the cutting member 19 passes through the ultrasonic horn 7. Ultrasonic vibration occurs in the direction indicated by arrow 61. Also, under the control of the control device 51, the XY table 10
It moves at a predetermined moving speed in the direction of arrow 66 along the ultrasonic vibration direction indicated by. The moving speed is a speed at which the stud bump 3a can be cut properly and the electrode pad 64 is not damaged, and is set appropriately according to the size and material of the bump pedestal 3. Therefore, the blade member 19
5 moves the XY table 10 in the direction of the arrow 66 while moving the XY table 10 while ultrasonically oscillating, and as shown in FIG. Cutting off. Therefore, when the cutting of the stud bump 3 a by the blade member 191 is completed, the remaining bump 131 having the thickness dimension III is formed on the electrode pad 64. After the cutting of the stud bump 3a is completed, as shown in FIG.
By bringing the suction port 20a of the removing device 20 close to the cut portion and performing a suction operation, the cut stud bump 3a is suctioned and removed from the semiconductor element 4.

Next, in step 4, the bump forming apparatus 16 forms a new stud bump 3a again on the electrode pad 64 from which the stud bump 3a has been cut. That is, since the control device 51 has the position information of the X and Y coordinates of the stud bump 3a determined to be defective as described above, the control device 51 moves the XY table 10 based on the position information to cut the stud bump 3a. The bump forming device 16 is moved to the position of the electrode pad 64 where the operation has been performed. After that, the stud bump 3a is re-formed by the same operation as the above-described stud bump 3a forming operation.

As described above, according to the bump bonding apparatus 101 of the present embodiment, once the semiconductor element 4 is placed on the heat stage 12, the formation and inspection of the stud bump can be performed without handling the semiconductor element 4 thereafter. The removal of defective stud bumps and the re-forming of stud bumps can be performed automatically and continuously. In particular, the operation of removing a defective stud bump can be performed with a more stable quality than a manual operation by a conventional operator. Therefore, it is possible to continuously produce ICs on which good-quality stud bumps are formed, and it is possible to reduce the cost of conventional inspection personnel.

In the above embodiment, the stud bump 3a is inspected every time the stud bump 3a is formed, and if the stud bump 3a is defective, the stud bump 3a is cut. However, the present invention is not limited to this. After forming the stud bumps 3a on the pads 64, the inspection may be performed, the cutting operation may be performed collectively thereafter, and then the re-forming operation of the stud bumps 3a may be performed collectively.

[0022]

As described above in detail, according to the bump cutting apparatus of the first embodiment of the present invention, the stud bump is cut by the cutting member which vibrates ultrasonically, so that the stud bump can be cut easily and the semiconductor is cut. This can be performed without damaging the element. Therefore, it is possible to produce an IC of lower cost and more stable quality as compared with the case where the operator manually cuts the IC, so that the productivity of the IC can be improved.

Further, according to the bump bonding apparatus of the second aspect of the present invention, there is provided a bump forming apparatus and a bump cutting apparatus, and when a stud bump formed by the bump forming apparatus is defective, the bump cutting apparatus provided in the same apparatus. Can cut defective stud bumps, so that it is possible to improve the productivity of inexpensive and stable quality non-defective ICs as compared with a conventional case where an operator cuts manually.

Further, according to the bump bonding method of the third aspect of the present invention, the stud bump formed in the bump forming step is inspected in the inspection step. Since the stud bumps can be cut, non-defective ICs of stable quality can be automatically and continuously produced, and the productivity of the ICs can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a bump bonding apparatus according to an embodiment of the present invention.

FIG. 2 is a side view of the bump cutting device shown in FIG.

FIG. 3 is a plan view of an example of a blade member provided in the bump cutting device shown in FIG.

FIG. 4 is a plan view of another example of the blade member provided in the bump cutting device shown in FIG.

FIGS. 5A to 5D are views showing a cutting operation of a stud bump.

FIG. 6 is a flowchart showing a stud bump cutting operation.

7 is a diagram showing a configuration of the inspection device shown in FIG.

FIG. 8 is a side view of a conventional bump forming apparatus.

FIGS. 9A to 9F are diagrams showing an operation of forming a stud bump.

[Explanation of symbols]

3a: stud bump, 4: semiconductor element, 7: ultrasonic horn, 8: ultrasonic oscillator, 16: bump forming apparatus, 17
... Inspection device, 18 ... Bump cutting device, 19 ... Cutting member,
Reference Signs List 20 removing device, 51 control device, 101 bump bonding device, 191 blade member, 192 mounting member, 1
93: fixing member.

Claims (7)

[Claims] 1. A cutting member (19) for cutting a stud bump (3a) formed on an electrode pad of a semiconductor element along the electrode pad near the electrode pad by ultrasonic vibration; An ultrasonic oscillator (7, 8) for applying the ultrasonic vibration to a member. 2. A bump bonding apparatus having a bump forming apparatus (16) for forming a stud bump (3a) on an electrode pad formed on a semiconductor element, wherein the stud bump formed by the bump forming apparatus is used. A cutting member (19) for cutting the defective stud bump along the electrode pad in the vicinity of the electrode pad by ultrasonic vibration when it is defective; and an ultrasonic oscillation for applying the ultrasonic vibration to the cutting member. A bump bonding apparatus comprising: a bump cutting device (18) having a device (7, 8). 3. An inspection device for determining the quality of the stud bump formed on the electrode pad by the bump forming device; and information from the inspection device that the inspected stud bump is defective. Position information on the defective stud bumps supplied and supplied from the inspection device in the direction along the formation surface of the electrode pads on the semiconductor element, and studs obtained at the time of forming the stud bumps supplied from the bump formation device The control device (51) for controlling a cutting operation of a stud bump by the bump cutting device based on height information of a pedestal portion of the bump and known thickness information of the electrode pad. Bump bonding equipment. 4. A bump removing apparatus for removing stud bumps cut by the bump cutting apparatus, wherein the bump forming apparatus forms stud bumps again on the electrode pads from which the defective stud bumps have been removed. Do
The bump bonding apparatus according to claim 2. 5. A bump forming step of forming a stud bump on an electrode pad of a semiconductor element; an inspection step of determining whether the stud bump formed in the bump forming step is good; and a stud bump in the inspection step. A cutting step of cutting the defective stud bump along the electrode pad in the vicinity of the electrode pad by an ultrasonic vibration cutting member when it is determined that the bump is defective. Method. 6. The bump bonding method according to claim 5, further comprising a bump re-forming step of forming a stud bump again on the electrode pad from which the stud bump has been cut in the cutting step. 7. A positional information of the defective stud bump obtained in the inspection step in a direction along a surface on which the electrode pad is formed on the semiconductor element, and a stud bump obtained in forming the stud bump in the bump forming step. 7. The bump bonding method according to claim 5, wherein a cutting operation of a stud bump in the bump cutting step is controlled based on height information of the base portion and known thickness information of the electrode pad.