JPH06258047A - Teaching method of bump data inspection data - Google Patents

Abstract

PURPOSE:To save labor and time required for teaching an inspection data significantly. CONSTITUTION:Automatic inspection data for bump is taught using a reference wafer 1S on which each bump is formed well. The image of a first chip T1 at the lower left end of time wafer 1S is picked up at first to produce an image for teaching color parameter information C1-C4, e.g. positional coordinates and threshold of each bump B11-B14 the inspection reference information P1-P4 for deciding pass/fail of bump, etc. Inspection data is similar for other chips T1 except the positional coordinates of bump and each data is stored, as a common data file 25, in a memory 13 at a control processing section. When inspection data for other chips Bi1-Bi4 is taught, the positional coordinates of each bump Bi1-Bi4 are taught and the data of the common data file 25 is used, as it is, as the inspection data for the bump group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic bump inspection apparatus used for automatically inspecting the shape of each bump formed on a wafer by using an image processing technique. The teaching method for teaching the data necessary for the inspection of the automatic inspection device.

[0002]

2. Description of the Related Art A conventional IC or LSI is formed by leading a lead wire to the periphery of a chip by wire bonding and electrically connecting it to a package side lead. However, in this type of connection structure, there is a problem that not only the connection work is troublesome, the cost of the product becomes high, but also the high density of the circuit and the miniaturization of parts cannot be dealt with.

Therefore, in recent years, a method of forming a large number of connecting electrodes called bumps on the surface of a chip and directly electrically connecting the chip to a substrate via these bumps has been put into practical use.

The material of the bump is a fine sphere such as gold or solder, and its diameter is usually 100 to 200 μm.
It is of a degree. If the shape of this bump is bad,
Since a defective connection occurs, it is essential to inspect the quality of bumps, but conventionally, such an inspection relies on visual inspection using a microscope.

Since several hundred bumps are usually formed for each chip, the number of bumps for one wafer is in the unit of tens of thousands, and it is not possible to inspect all bumps on a wafer by conventional visual inspection. Practically impossible. For this reason, the bumps on the wafer are randomly extracted and inspected, and there is a problem that the generation of defective products cannot be completely suppressed.

Therefore, the applicant has recently proposed an automatic bump inspection apparatus for automatically inspecting the quality of bumps on a wafer by using image processing technology to perform highly accurate inspection without manual labor.

When using this bump automatic inspection apparatus,
Prior to the inspection, it is necessary to teach the bump automatic inspection apparatus what kind of bumps are formed at what positions on the wafer to be inspected for each type of wafer. This teaching work is generally called "teaching".

Information related to inspection of bump quality (hereinafter,
The “inspection data”) includes, in addition to the position and type of bumps on the wafer to be inspected, information about the window (shape, size, etc.) set as the inspection area, and information about each bump on the wafer ( (Shape, length, width, etc.), information about characteristic parameters (such as hue and brightness) indicating the formation state of bumps, and judgment criteria for judging the quality of characteristic parameters.

[0009]

By the way, on the wafer,
A large number of bump groups having the same configuration are formed on a chip-by-chip basis, and the inspection data for each bump group is the same except for the position of each bump. Nevertheless, since the same inspection data is repeatedly taught for each bump, the teaching work requires a great deal of labor and time, and a huge memory capacity is required to store all the teaching data. There's a problem.

The present invention has been made in view of the above problems. By diverting the inspection data for a specific group of bumps during teaching, the labor and time required for teaching can be greatly reduced and the teaching can be performed. It is an object of the present invention to provide a bump inspection data teaching method capable of significantly reducing the memory capacity for storing data.

[0011]

SUMMARY OF THE INVENTION The present invention is a method of teaching inspection data to a bump automatic inspection apparatus for automatically inspecting each quality of a plurality of bumps formed on a wafer. It is characterized in that the set of inspection data taught to the above-described bump automatic inspection device for one group is diverted to the inspection data for each bump included in another group of bumps to teach it to the automatic bump inspection device.

In the invention of claim 2, the data for teaching the bump automatic inspection apparatus includes position data of all bumps on the wafer, and in the invention of claim 3, a group of specific bumps is set. It includes position data of each of the bumps that are formed and relative position data of a group of other bumps with respect to the group of the specific bumps.

[0013]

Since the inspection data taught for a specific group of bumps on the wafer is used as the inspection data for another group of bumps having the same structure as this group of bumps, the labor and time required for the teaching can be reduced. Is greatly reduced.

According to the invention of claim 3, as the position data of each bump, position data for a group of specific bumps and relative position data for a group of the other specific bumps are taught. Therefore, the memory capacity for storing the teaching data is reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall structure of an automatic bump inspection apparatus. This automatic bump inspection apparatus is provided with each bump 2S on the reference wafer 1S obtained by imaging the reference wafer 1S.
Of the inspection area and the characteristic parameters of the inspection area of each bump 2T on the inspection wafer 1T obtained by imaging the inspection wafer 1T are compared to inspect the quality of each bump 2T. The configuration includes an X-axis table unit 3, a Y-axis table unit 4, a light projecting unit 5, an imaging unit 6, a control processing unit 7, and the like as its configuration.

The X-axis table section 3 and the Y-axis table section 4 each include a motor (not shown) that operates based on a control signal from the control processing section 7, and the X-axis table section is driven by these motors. The unit 3 moves the image pickup unit 6 in the X direction, and the Y-axis table unit 4 moves the wafers 1S, 1T.
The conveyor 8 supporting the is moved in the Y direction.

The light projecting unit 5 is composed of three annular light sources 9, 10, 11 having different diameters and irradiating green light, red light, and blue light simultaneously based on a control signal from the control processing unit 7. The light sources 9, 10 and 11 are arranged so as to be centered directly above the inspection position and to correspond to different elevation angles when viewed from the inspection position.

In this embodiment, a white light source is used as each of the light sources 9, 10 and 11 and a green, red and blue colored transparent plate is covered, but instead of this, a green light,
It is also possible to use three annular color fluorescent lamps or neon tubes that generate red light and blue light, respectively.

Next, as the image pickup section 6, a color television camera is used, and the image pickup section 6 is positioned right above the inspection position so as to face downward. As a result, the wafers 1S and 1T to be inspected are
The reflected light on the surface of is imaged by the imaging unit 6, converted into color signals R, G, B of the three primary colors and supplied to the control processing unit 7.

The control processing unit 7 includes an A / D conversion unit 12, a memory 13, a teaching table 14, an image processing unit 15,
It is composed of a determination unit 16, an XY table controller 17, an image pickup controller 18, a display unit 20, a printer 21, a keyboard 22, a floppy disk device 23, a control unit 24, etc., and has been carried into the inspection position in the teaching mode. Color signal R for the reference wafer 1S,
G and B are processed, and characteristic parameters such as red, green, and blue hues and brightness are applied to the inspection area of each bump of the reference wafer 1S to create a judgment data file.

In the inspection mode, the wafer 1T to be inspected
Process the color signals R, G, B, to detect the red, green, and blue color patterns in the inspection area of each bump 2T on the inspection wafer 1T, generate characteristic parameters, and create an inspection data file. To do. Then, the inspection data file is compared with the determination data file, and the quality such as the quality of the shape of each bump 2T on the inspection wafer 1T is automatically determined from the comparison result.

FIG. 2 shows that when the bump shape is good,
When bumps are missing, when the bump shape is defective, sectional shapes of the bumps 44 to 46, and the imaging unit 6 in each case
The relationship between the image pickup pattern, the red pattern, the green pattern, and the blue pattern is illustrated in a list.

In the image pickup pattern shown in FIG.
Reference numerals 0R and 30B are a green area, a red area, and a blue area, which are generated when the green light, the red light, and the blue light are specularly reflected on the bump surface and are incident on the imaging unit 6. 30BL
Is a black region generated because neither specular reflection light of any light is incident on the imaging unit 6 or the amount of incident light is small.
Reference numeral 31G is a light green region generated by the mixed light being reflected on the green background and being incident on the imaging unit 6. Therefore, the green pattern has green areas 30G and 31G, the red pattern has red area 30R, and the blue pattern has blue area 3.
0B is extracted and appears.

According to the figure, each color pattern when the shape of the bump is good and each color pattern when the bump is missing and when the shape of the bump is defective are clearly different. Therefore, it is possible to determine the presence / absence of bumps and the quality of bumps by comparing each color pattern of the inspection target with a normal color pattern.

Even if the bumps are not missing and the shape of the bumps is not defective, the outer peripheral edge of the black region 30BL corresponds to the outer shape of the bumps seen from above. Direction or Y direction diameter D
_X, by calculating the area within D _Y and the outside of the green region 31G, it is possible to obtain the size of the bump, it can determine the frequency assay and the size of the quality of the size of the bump. Also X
The degree of distortion of the bump shape can be determined by calculating the ratio between the diameter D _X in the direction and the diameter D _{Y in the} Y direction and the circularity (4π × area / perimeter ² ).

Further, since the width of each light source 9, 10, 11 and the distance between the light sources and the height of each light source 9, 10, 11 are determined, the width of each light source 9, 10, 11 and the distance between the light sources are determined. By measuring from each color pattern, the height of the bump can be calculated, and it is possible to judge whether the height of the bump is good or bad.

Returning to FIG. 1, the A / D conversion unit 12 converts the color signals R, G, B from the image pickup unit 6 into digital signals and outputs them to the control unit 24. The memory 13 includes a RAM and the like and is used as a work area of the control unit 24.
The image processing unit 15 performs image processing on the image data supplied via the control unit 24 to create the inspection data file and the determination data file, and these are processed by the control unit 24 and the determination unit 1.
Supply to 6.

The teaching table 14 stores the judgment data file when it is supplied from the control unit 24 at the time of teaching, and when the control unit 24 outputs a transfer request at the time of inspection, the judgment data file is stored according to this request. It is read and supplied to the control unit 24, the determination unit 16 and the like.

The determination section 16 compares the determination data file supplied from the control section 24 at the time of inspection with the inspected data file transferred from the image processing section 15 for each bump 2T of the inspected wafer 1T. The quality of the bump shape is determined, and the determination result is output to the control unit 24.

The image pickup controller 18 includes an interface for connecting the control unit 24 to the light projecting unit 5 and the image pickup unit 6, and adjusts the light amount of each of the light sources 9 to 11 of the light projecting unit 5 based on the output of the control unit 24. Control is performed or the mutual balance of the light output of each hue of the image pickup unit 6 is maintained.

The XY table controller 17 is a controller 2
4 is provided with an interface for connecting the X-axis table unit 3 and the Y-axis table unit 4, and controls the X-axis table unit 3 and the Y-axis table unit 4 based on the output of the control unit 24.

The display unit 20 receives image data, inspection results, key input data, etc. from the control unit 24,
This is displayed on the display screen, and when the inspection result and the like are supplied from the control unit 24, the printer 21 prints out this in a predetermined format.

The keyboard 22 is provided with various keys necessary for inputting operation information and data relating to the reference wafer 1S and the wafer to be inspected 1T, and the key input data is supplied to the control section 24. The control unit 24 includes a microprocessor and the like, and controls the operation of the bump automatic inspection device in teaching and inspection according to the procedure described later.

In this embodiment, when teaching the inspection data of each bump to the automatic bump inspection apparatus, after instructing the inspection data of a specific bump group, that is, the bump group of one chip here, this inspection is performed. Data is used as inspection data for the bump group of another chip and taught to the automatic bump inspection apparatus.

3 and 4 show an example of teaching,
The teaching procedure will be described below with reference to FIG. 3 while referring to FIGS. The reference wafer 1S illustrated in FIG. 4 (1) has four bumps B _i1 , B _i2 , B _i3 , and B _i4 ) of the same structure formed on each chip T _i for convenience of description. And

First, in step 1 of FIG. 3, the operator operates the keyboard 22 to register the name of the wafer to be taught, and after key inputting the wafer size, in the next step 2, the reference wafer 1S is set to Y. Axis table part 4
Set it up and press the start key. Next, in step 3, the origin of the reference wafer 1S and the upper right and lower left corners are imaged by the imaging unit 6 and the actual size of the reference wafer 1S is input according to the position of each point. Based on the data, the X-axis table unit 3 and the Y-axis table unit 4 are controlled to set the reference wafer 1S to the initial position, that is, the first chip T ₁ (the reference wafer 1S in the example of FIG. 4A).
Position on the bottom left tip).

The reference wafer 1S has a good shape in which predetermined bumps 2S are properly formed at the bump forming positions. When the reference wafer 1S is positioned at the initial position, the next step 4 Then, the image pickup unit 6 picks up an image of the bump group for the first chip T ₁ , teaches the position of each bump B _{11 to} B ₁₄ , and then extracts the characteristic parameters necessary for the automatic inspection of the bump from the picked-up image. Then, this is taught as inspection data (steps 5 to 7).

The inspection data taught at this time is shown in FIG.
As shown in (2), position coordinates (x ₁₁ , y ₁₁ ), (x ₁₂ , y ₁₂ ), (x ₁₃ , y ₁₃ ), of the bumps B _{11 to} B ₁₄ are obtained.
In addition to (x ₁₄ , y ₁₄ ), each bump B ₁₁ as shown in FIG.
~ 2 of brightness and chromaticity for extracting each color pattern of B ₁₄
Binarization threshold such information (hereinafter this "color parameter information" hereinafter) C ₁ ~C _4, the testing standards for determining the acceptability of the quality of the bump B ₁₁ .about.B ₁₄ information P ₁ to P _4, etc. is there.

The inspection data such as the color parameter information C _{1 to} C ₄ and the inspection reference information P _{1 to} P ₄ is the same for the bumps B _{i1 to} B _i4 of the other chips T _i. Are stored in the memory 13 as a test data file 25 common to all chips (hereinafter referred to as "common data file 25") (step 8).

In the next step 9, the image pickup device 6 is moved onto the next adjacent chip (in this case, the chip T ₂ on the right side of the chip T ₁ ), and in step 10, each bump B ₂₁ of the chip T ₂ is moved. ~ B ₂₄ is sequentially imaged and its position is taught. When the positions of all the bumps B _{21 to} B ₂₄ are taught,
Step 11 proceeds to step 12 is "YES", the control unit 24 reads the common data file 25 from the memory 13, teaches the inspection data corresponding for each of the bumps B ₂₁ .about.B ₂₄ (Step 1
2).

As shown in FIG. 4 (2), by the procedure of steps 10 to 12, the bump B ₂₁ has the same color parameter information C as the bump B _{11 in} addition to the position coordinates (x ₂₁ , y ₂₁ ). ₁ and the inspection reference information P ₁ are taught. Similarly, for bump B ₂₂ , the position coordinates (x ₂₂ , y
₂₂ ), color parameter information C ₂ and inspection standard information P ₂
For the bump B ₂₃ , position coordinates (x ₂₃ , y ₂₃ ), color parameter information C _3, inspection reference information P ₃ , and for the bump B ₂₄ position coordinates (x ₂₄ , y ₂₄ ), color parameter information C ₄ , The inspection standard information P ₄ is taught, and these pieces of information are stored in the determination data file 26.

In the same manner, the steps 9 to 12 are sequentially executed for each chip T _i , and each bump B
each position coordinate as test data for _i1 .about.B _i4, color parameter information, such as information of the inspection criteria are taught. Step 13 when the instruction for all chips is completed
Is “YES”, and in the next step 14, the control section 24 stores the judgment data file 26 having the content shown in FIG. 4B in the teaching table 14.

5 and 6 show other examples of teaching. This teaching is also performed by using the reference wafer 1S similar to that shown in FIG.
Then, after performing the procedure similar to steps 1 to 3 of FIG.
Reference point t _i for each chip T _i in step 4 following
The position (shown in FIG. 6 (1)) is taught. In addition to the manual input by the operator, the teaching of the reference point t _i
It is also possible to use CAD data or the like used when a wafer is created.

In the next step 5, as in the first embodiment, the reference chip T ₁ is imaged and each bump B ₁₁ is imaged.
~ B ₁₄ , position coordinates and color parameter information C ₁ ~
C _4, such as information P ₁ to P ₄ of the inspection criteria are sequentially taught as test data (step 6,7). When this teaching is completed, the determination in step 8 becomes "YES" and the process proceeds to step 9, and the control unit 24 collectively stores each taught data as a determination data file in the teaching table 14.

Judgment data file 2 created at this time
6'is composed of a reference data file 27 and a position data file 28 as shown in FIG. 6 (2). The reference data file 27 includes bumps B _{11 to} B ₁₄ for the _first chip T ₁ taught in steps 5 and 6 of FIG.
Inspection data, that is, position coordinates of each bump, color parameter information C _{1 to} C ₄ , and inspection reference information P _{1 to} P
_It is a memorized ₄ etc. The position data file 28 stores the coordinates (X _i , Y _i ) of the reference point t _i of each chip T _i stored in step 4 of FIG.

The reference point t _i is not limited to the position shown in FIG. 6A, but may be freely set at a position corresponding to each chip T _i .

FIG. 7 shows the procedure of the bump automatic inspection using the judgment data file 26 created by the procedure of FIG. 3, and the wafer name to be inspected is selected and bumps are selected in steps 1 and 2 of FIG. Perform automatic inspection start operation. The next step 3 is the wafer 1 to be inspected to the automatic bump inspection apparatus.
The supply of T is checked, and if the result of the determination is “YES”, the conveyor 8 is activated and the wafer to be inspected 1
T is carried in (step 4).

In step 5, the control section 24 controls the X-axis table section 3 and the Y-axis table section 4 to take an image based on the taught position coordinate data of the first bump 2T on the wafer 1T to be inspected. The visual field of the unit 6 is positioned and imaging is performed, and the inspection region is automatically extracted. In the next step 6, image processing is performed based on the instructed color parameter information to create an inspection data file. Then, the control section 24 transfers the inspected data file to the determination section 16, compares the inspected data file with the information of the corresponding inspection standard in the determination data file 26, and determines the first bump 2T. The quality such as the quality of the shape is judged (step 7).

When such an inspection is completed, it is checked in the next step 8 whether all the bumps on the wafer 1T have been inspected. If the judgment is "NO", the image pickup section 6 is operated in step 9. Is moved to the next bump 2T, and steps 5 to 7 are performed again for this bump 2T.
Perform the inspection according to the procedure.

When the above inspection is repeatedly executed for all the bumps 2T on the wafer 1T to be inspected, step 8 becomes "YES" and the process shifts to step 10 to check the presence or absence of defective bumps. As a result, if there is a defective bump, the defective bump and the content of the defect are output to the display unit 20 or the printer 21, and then the inspected wafer 1T is unloaded from the observation position (steps 11 and 12). Thus, when the same inspection procedure is executed for all the inspected wafers 1T, the determination in step 13 becomes "YES", and the inspection is completed.

FIG. 8 shows the procedure of the bump automatic inspection by the judgment data file 26 'created by the procedure of FIG. First, in steps 1 to 4, step 1 in FIG.
~ After the procedure similar to step 4 is executed, in the next step 5, the control unit 24 uses the position data file 28 to determine the reference point t _i of the tip T _{i and} the reference point t of the first tip T _1.
The position coordinates with ₁ are read out, and the pitches α _i and β _i in the X and Y directions with respect to the reference chip T ₁ of the chip T _i are obtained using the following equation.

[0052]

[Equation 1]

[0053]

[Equation 2]

At the next step 6, the control section 24 reads the data of the reference data file 27, changes the position coordinates of each bump to the original coordinates plus the pitches α _i, β _i , and changes this. It is stored in the memory 13 as inspection data of the chip T _i .

FIG. 9 shows the contents of the inspection data used to inspect each chip T _i . As is apparent from the illustrated example, the data in the reference data file 27 is used as it is as the inspection data for the first chip T ₁ . In addition, each bump B ₁ in the second and subsequent chips T _i
Check data for .about.B _4, for the position coordinates, data of the reference data file 27, i.e. the pitch alpha _i was calculated by the formula to the coordinates of the first chip T ₁ of the bumps B ₁ .about.B _4, beta _i is added, and other inspection data, that is, color parameter information C ₁ to
As for C ₄ and inspection standard information P _{1 to} P ₄ , the data of the standard data file 27 is used as it is.

Returning to FIG. 8, in the next steps 7 to 9,
An inspection (similar to steps 5 to 7 in FIG. 7) is performed on each bump on the chip T _i using the inspection data. In the next step 10, it is checked whether or not all the bumps on the chip T _i have been inspected. If this determination is “NO”, then in step 11, the image pickup device 6 is moved onto the next bump and again. Steps 7-10
Perform the inspection procedure in.

When the inspection of all the bumps on the chip T _i is completed, the inspection data of the chip T _i stored in the memory 13 is cleared in step 12, and in the next step 13, the inspection data on the wafer 1T is read. It is checked whether all chips T _i have been tested. When this determination is "NO", the process returns to step 5 and the same procedure as above is executed for the next chip T _i .

When all the chips T _i on the wafer 1T have been inspected, step 13 becomes "YES" and the process proceeds to step 14, and step 10 of FIG.
~ A procedure similar to step 13 is executed (step 1
4-17).

In the above two embodiments, the inspection data for the bump group of one chip is stored.
The present invention is not limited to this, and each embodiment can be similarly applied to a unit of a bump group of an arbitrary size such as a bump group of half of one chip or a bump group of two chips.

[0060]

As described above, according to the present invention, when inspecting each quality of a plurality of bumps formed on a wafer, inspection data for a specific group of bumps on the wafer is set to a group of other bumps. Since the data is used for the inspection data of each included bump, the labor and time required for teaching can be significantly reduced. According to the invention of claim 3, the position data of each bump is taught for a group of specific bumps, and the relative position data for the group of specific bumps is taught for another group of bumps. It has a remarkable effect of achieving the object of the invention, such as a significant reduction in capacity.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the overall configuration of an automatic bump inspection apparatus.

FIG. 2 is an explanatory diagram showing the relationship between the quality of the bump shape and the pattern.

FIG. 3 is an explanatory diagram showing a procedure of teaching by a control processing unit.

FIG. 4 is an explanatory diagram showing a configuration of a reference wafer and a configuration of a determination data file.

FIG. 5 is an explanatory diagram showing a second teaching procedure by a control processing unit.

FIG. 6 is an explanatory diagram showing a structure of a reference wafer and a structure of a determination data file.

FIG. 7 is a flowchart showing a procedure of automatic inspection.

FIG. 8 is a flowchart showing a procedure of a second automatic inspection.

9 is an explanatory diagram showing inspection data for each chip in the procedure of FIG. 8. FIG.

[Explanation of symbols]

 1S, 1T wafer 2S, 2T bump 7 control processing unit 13 memory 14 teaching table 24 control unit 25 common data file 26 26 'judgment data file 27 reference data file 28 position data file

Claims (3)

[Claims] 1. A method of teaching inspection data for automatically inspecting each quality of a plurality of bumps formed on a wafer to an automatic bump inspection apparatus, the automatic bump inspection apparatus for a group of specific bumps. A method for teaching bump inspection data, characterized by diverting the set of inspection data taught by the above into the inspection data of each bump included in a group of other bumps and teaching the same to an automatic bump inspection apparatus. 2. The method for teaching bump inspection data according to claim 1, wherein the data for teaching the bump automatic inspection apparatus includes position data of all bumps on the wafer. 3. The data to be taught to the automatic bump inspection apparatus includes position data of each bump forming a group of specific bumps and relative position data of another group of bumps to the group of specific bumps. The method for teaching bump inspection data according to claim 1, further comprising: