JPS5941847A - Device for displaying pattern defect - Google Patents

Abstract

PURPOSE:To obtain an inexpensive device for displaying pattern defects, by processing images by using a computer and software, making it possible to change inspection criterion for inspection readily, and facilitating recognition. CONSTITUTION:A standard IC chip 100 is placed on a mounting part 5a of a sample table 5. An operation command is inputted to a CPU22 from a key input device 23 through keys. Then control signals are outputted to a mounting part movement controlling circuit 9 and a focal point adjustment controlling circuit 10. Based on said control signal, the mounting part movement controlling circuit 9 moves the mounting part 5a back and forth and right and left through a mounting part moving mechanism 6 and positiones the standard IC chip 100 at a specified location with respect to an objective lens 2. The focal point adjustment controlling circuit 10 adjusts the focal point of the objective lens 2 with respect to the standard IC chip 100 through a focal point adjusting mechanism 7. Then, the image of the pattern of the standard IC chip 100 is taken out of a microscope 1 through reflecting mirrors 8a, 8b, and 8c, and transduced into an image signal by a photoelectric transducer circuit 11.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for inspecting pattern defects in patterned bodies such as semiconductor chips and printed circuit boards, and for displaying abnormal areas. , - It is characterized by determining the result of manual processing of the pattern and displaying the normal part (! - in a color that clearly identifies it) so that it can be clearly seen.

An example of an apparatus for inspecting pattern defects in a semiconductor chip of a semiconductor integrated circuit will be described below.

FIG. 1 is a block diagram showing the configuration of an example of a conventional pattern defect inspection apparatus. In the figure, (1) is a microscope, (2) and (3) are respectively the objective lens and eyepiece of the microscope (1), and (4) is a holding pedestal that holds the microscope (1) so that it can move up and down. (5) A sample stand attached to the holding stand (4j and provided so that the placing part (5a) on which the IC chip to be inspected (1σ0) is placed can be moved back and forth and left and right; (6) is a holding stand ( 4), and the sample stage (
5) a placing part moving mechanism for moving the placing part (5a);
7) moves the microscope (1) installed on the holding stand (4) up and down to measure the amount of test material C chip (10) of the objective lens (2).
0), (8a), (8t'
) and (8C)Vi objective lens (2) This is a reflector that takes out the image of the 7" (100) pattern from inside the microscope (1) to the outside. (9) (10) is a focus adjustment control circuit that controls the focus adjustment mechanism (7), (11) is a TV right camera, and a microscope ( 1) A photoelectric conversion circuit that converts the image of the pattern of the inspected C chip (100) taken out from inside through the reflecting mirror (8a x 8t) and (8C) into an image signal and outputs the image signal, (12) is The image signal amplification circuit (13) amplifies and outputs the image signal output from the photoelectric conversion circuit (11), and the A/D conversion circuit (13) converts the image signal output from the image signal amplification circuit (12) into a digital image signal. The circuit (14) is a quantization processing circuit that divides the image signal output from the image signal amplification circuit (engine 2) into a plurality of fractional image signals, quantizes and outputs these fractional image signals. , (15) is a processing screen determining circuit that determines and outputs the portion of the image signal outputted from the image signal amplification circuit (12) that corresponds to the processing screen, and (16) is a photoelectric converter (11) that outputs the image signal. Amplification circuit (
12), quantization processing circuit (14) and processing screen determination circuit (
(15) a synchronization signal generation circuit that outputs a synchronization signal to (17);
), an image analysis circuit that extracts and processes data signals of characteristic variations such as the length, area, and shape of the pattern of the XC chip (100) to be scanned from the digital image signal outputted by the A/D conversion circuit (13); 18) is an image analysis circuit (1
7) is a temporary storage device that stores data signals of extracted feature parameters. Note that this temporary storage device
(18) is the percentage characteristic parameter data of the pattern of the standard IC chip (100) without defects, which is also stored in advance. (19) is the fraction 1-image quantized signal output from the quantization processing circuit (14) and the processing screen determination circuit (1
Based on the image signal corresponding to the processing screen outputted from 5) and the data signal of the characteristic parameter outputted from the image analysis circuit (17), predetermined arithmetic processing is performed in CL to calculate the This is an arithmetic processing circuit that calculates numerical values such as length, area, shape, etc. necessary for bar':! Compare the values calculated from the data signals of the characteristic variations of the pattern of the standard IC chip (100) stored in the storage device (18),
Blink or block the comparison result as a message.
The image is displayed on the display device (20), etc., and is also displayed as an image on the monitor TV ground display (21), and at the same time, the control signal accompanying the completion of the calculation is sent to the mounting unit movement control circuit (9) and the focal point sub-control cape. Output to the circuit (lO).

Next, the operation of this conventional example will be explained. First, the IC chip to be inspected (100) is placed on the holder lf part (5a) of the sample stage, and a control signal is sent to the holder Ii 1 movement control circuit (9) and the focus adjustment side circuit (10). The placing part movement control circuit (9) connects the placing part (5a) via the placing part moving mechanism (6).
) to the r4tJf&left and right and use the C-chip (
IOLI) is placed at a predetermined position with respect to the objective lens (2), and the focus-control circuit (10) is connected to the focus adjustment mechanism (7).
[through] the IC chip to be inspected (10) of the left lens (2)
Focus on m[0').

Next, one pattern image of the temporary inspection C-chip (100) is taken out from inside the microscope (1) via reflection a (8a), (8k)) and (8C) and transferred to the charging conversion circuit (II).
It is converted into a −鑵 signal.

Next, this image signal is amplified by a uniform signal amplification circuit (12), and this amplified image signal is converted into a digital image signal by an A/D conversion circuit (13) and is subjected to quantization processing. The circuit (14) divides the signal into multiple image signals,
At the same time, the amplified image signal corresponding to the processing screen is quantized for each image signal by the processing screen determination circuit (15).
) is determined. In between, a photoelectric conversion circuit (11), an image signal amplification circuit (12), an A/D conversion circuit (13),
Quantization processing circuit (14) and processing screen determination circuit (15)
Their operations are synchronized by a synchronization signal output from a synchronization signal generation circuit (16). Next, from the digital image I-image signal converted by the A/D conversion circuit (13), data signals of characteristic parameters of the pattern of the inspected C-chip (100) are extracted and processed by the image analysis circuit (17) and stored in a temporary storage device. (18) K can be stored.

Thereafter, in the arithmetic processing circuit (19), the image quantization No. 1a from the quantization processing circuit (14), the processing screen corresponding image signal from the processing screen determination circuit (15), and the image signal from the image analysis circuit (17) are processed. Predetermined arithmetic processing is performed based on the data signal of the characteristic parameters, and the IC chip to be inspected (10
The fx number required for recognizing the pattern of tJ) is calculated.

Then, fI! obtained by this calculation process! The 11th shift is compared with the numerical value calculated from the data signal of the characteristic parameter of the pattern of the standard IC chip (100) stored in the temporary storage device (18) in advance. For example, it is calculated from the data signal of the characteristic parameter of the defect-free aluminum (A/) wiring film (101a) of the standard IC chip (100a) stored in the temporary storage device (18) and whose plan view is shown in FIG. 2(A). The numerical values and parts S and D shown in the figure
When compared with the numerical value calculated from the data signal of the characteristic variation of the Al wiring film (1011) with defects in the part,
Al wiring film (101) of IC chip to be inspected (1001)
1)) The numbers in part 8 and part D are standard IC chips (
The above 8 parts of the Al wiring film (101a) of 100a) and D
Since the value is different from the value in the part corresponding to the part, all! of the Al wiring film (101b) of the IC chip (100b) is different. and a defect in part D is detected. These defects are displayed on the display device (20) with a message indicating that there is a defect, and an image is displayed on the monitor TV screen.

By the way, in conventional devices, when there is a defect, it is displayed as a message in text or the processed result is displayed in a pattern diagram. When displaying in text like this, you can immediately tell that there is a defect, but you cannot immediately see its location. Furthermore, when displayed as a pattern diagram, it is difficult to locate the defect. In addition, since the inspection criteria for inspecting pattern defects in the conventional example is fixed by the hardware that performs image processing, there is a drawback that it is not easy to change the inspection criteria, and the configuration of the hardware is complicated and expensive. There were disadvantages such as high cost.

This release L! A was made in view of the above points, and by using a computer to perform image processing using software, the inspection standards for checking pattern defects can be easily changed, and defective areas can be easily changed. The purpose of this invention is to provide an inexpensive display device for pattern defects by controlling them using color codes to facilitate identification.

FIG. 3 is a block diagram showing the structure of a pattern defect display device according to an embodiment of the present invention. In the candy in the same figure, the same reference numerals as in the conventional example shown in FIG. 1 indicate the same parts, and the explanation thereof will be omitted. (22) is a central processing unit f (hereinafter referred to as "CPU") which performs image processing of the digital image number fa output from the A/Dg conversion circuit (13). (23)
KECL'U (22) A human-powered device that manually inputs control commands, (24) KECP U (22) is a dOM that stores a series of control programs for floor treatment.
・25) Sharpening of the standard C chip (lυ0) (a
(26) is a temporary storage device that stores the identification signal of the pattern of the IC chip to be inspected (100); (27) is a color code memory in which the code corresponding to the specified color is stored. Color code memory.

(28) is a standard storage device (25) and a temporary storage device (
26) is an auxiliary storage device such as a magnetic tape or a magnetic disk used in the case of overflow or to store data signals separately.

Next, the operation of this embodiment will be explained. First, place the standard C chip (ioo) on the mounting part (5a) of the sample stage (5).
CPU (22) from the human power device (23)
When you input the activation command manually, c p U (22
) outputs a control signal to the platform movement control circuit (9) and the focus adjustment control circuit (10), and this control signal +1111 causes the platform movement control circuit (9) to control the movement of the platform. The standard IC chip (100) is placed at a predetermined position with respect to the objective lens (2) by moving the mounting part (5a) back and forth and left and right through the mechanism (6), and the focus adjustment control circuit (10) adjusts the focus. The focus of the objective lens (2) on the standard C depth (100) is adjusted via the adjustment mechanism (7). Next, the pattern of the standard C-chip (100) is taken out from inside the microscope (1) via reflection jumps (8a), (8t') and (8c), and is sent to the photovoltaic conversion circuit (11). converted into an image signal. This image signal is amplified by the image signal amplification circuit (12), and this amplified image (No. F1 is the A/Dffi Boku circuit (
13), it is converted into a digital image signal and sent to the CPU (2
2) through the input port and synchronized with the synchronization signal output by the generating circuit (16). Then,
The digital image signal of the pattern of the standard IC chip (100) outputted from the A/D conversion circuit (13) to the CPU (22) is stored in the ROM in the CPU (22).
According to the control 11 program stored in (24), picture one image obfuscation (No. 771) is stored in the standard storage device (25).

In this way, the image of the 4s semi-engineered C chip (1oo) It'
With the quantized signal stored in the standard storage device (25), the p-111 C chip (100) t-sample stage I5)
of! When it is placed on the R placement part (5a) and an operation command is input manually from the manual device (23) to the c p u (22), the same functional operation as in the case of the standard IC chip CIGO described above is performed. , a digital image signal of the pattern of the IC chip to be inspected (100) is output from the A/D conversion circuit (13) to the CPU (22) through the input port. Then, at cpσ (22), this digital image signal is stored in the temporary storage device (26) as a quantized image signal according to the control program stored in the ROM (24). 26)
The image quantization signal stored in the standard storage device (25) is compared with the image quantization signal stored in the standard storage device (25). At this time, if there is a mark and a signal generated based on it, the color code memory (27) is accessed, and the data is outputted via the hot controller for the monitor TV Brown f (21
) to output the specified color. For example, a defect-free A/wiring IA (101
As shown in FIG. 4(A) of a), the standard storage device (25
) and the image quantized signal stored in (B) K”
Al wiring film (101t) with defects in the S part and D part of the IC chip to be inspected (100b) showing the IL direction view
As shown in FIG. 4(B), the temporary storage device t (26)
The image quantized signal stored in At this time, the code for r41 indicated by diagonal lines in Fig. 4(E) is the second code.
Since they correspond to the defective parts S and D in Figure (B), the color code memory (27) is accessed as described above when a defect is detected, and the color control part of the monitor TV ground f (21) is controlled. The defect is displayed in a pre-specified color. Therefore, the defective part can be clearly seen at a glance.

In this way, in the device of this embodiment, the image processing by the CPU (22) is performed by the ROM (24) K storage and 1N
-C press. 1 in accordance with 224. A. By changing only the control program stored in the ROMC 24) without changing the hardware that performs image processing as in the conventional example shown in Fig. 1, it is possible to change the image size, etc. By specifying data, the color code for displaying defective parts can be changed, and inspection standards for pattern defects can be easily changed.

Furthermore, the configuration of image processing using c P U (22) is simple and the price is low. Note that in this embodiment, the Sakatoshi IC
We have described the case of image processing of the pattern of the chip (100), but as in the conventional example shown in FIG.
Needless to say, even when extracting the characteristic parameters of the chip (100) and performing image processing, there are young fruits similar to those in this embodiment. Furthermore, by specifying a color code, defects can be classified by color. For further display,
It can be displayed not only on TV, but also on printers, blocks, etc. as necessary. Until now, IC chips (10
Although the device for displaying pattern defects in υ) has been described as an example, the present invention is not limited thereto, and can be applied to inspecting and displaying defects in printed circuit boards and other pattern-formed bodies.

As described above, in the pattern defect display device of the present invention, image processing is performed on a digital image signal corresponding to a pattern of a standard pattern forming body without defects in accordance with a control program stored in a ROM. a standard image data signal obtained by subjecting No. 8 to one-image processing according to the above-mentioned control program; By comparison, it detects human defects in the above-mentioned Bakun-type 1-absence pattern to be inspected, and uses software processing to clearly display the defective part by specifying a color code, so it does not work as in the conventional example. By simply changing the side program stored in the ROMK or the specified code data without changing the hardware that performs image processing, the inspection criteria for pattern defects on the patterned body can be easily changed, and the inspection criteria for pattern defects can be easily changed. It is possible to display parts so that they can be clearly identified.Moreover, the above image processing configuration
It's easy and can be done cheaply.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing an example of a conventional device, and Figure 2 (
A) and (B) are plan views showing an example of a standard IC chip and an example of inspected C-chiping, respectively; FIG. 3 is a block diagram showing the configuration of a pattern defect display device according to an embodiment of the present invention; FIG. (A) is a diagram showing an example of the image 11J quantized signal stored in the standard storage device of the above embodiment and corresponding to the standard XC chip A/wiring film in the second section, FIG. 4 CB
) is stored in the temporary storage device of the above embodiment, and is shown in FIG.
) is a diagram showing an example of an image quantized signal corresponding to the AI wiring pattern of the failure inspection IC chip. (1)...Microscope, (2)...Objective lens, (3)
...Eyepiece, (4)...Holding stand, (5)...
Sample stage, (5a)...Placement part, (6)...Placement part movement mechanism, (7)...Focus adjustment mechanism, (100)...Cig, (8a), (8b ), (80)--reflector, (9)--placement part movement control circuit, (10)-focus adjustment control circuit, (11)--photoelectric nine conversion circuit, (12)--
...Image 1 = signal amplification circuit, (13)...A/D conversion circuit, (14)...quantization processing circuit, (15)...
・Processing screen determination circuit, (16)...Synchronization signal generation circuit, (17)...Image analysis circuit, (18)...Storage device, (19)...Arithmetic processing circuit, (20)...・Display device, (21)...TV gracun tube, (22)...C
PU, (23)...key human power device, (24)...f(O
M, (25)...Standard storage device, (26)...Temporary storage device, (27)...Color code memory, (28)...Auxiliary storage device.

Claims (1)

[Claims] A photoelectric conversion circuit that converts an image of a pattern on a pattern forming body into an image signal and outputs the image signal; and A/
A D conversion circuit, a central processing unit that performs image processing on a digital image signal output by the A/D conversion circuit according to a control program, a read-only memory that stores the control program, and the pattern formation body that is a defect-free standard. A standard storage device that stores standard image data obtained by converting the image of the pattern into digital image signal pressure through the photoelectric conversion circuit and the A/D fb circuit and performing image processing; A temporary storage device that converts the pattern painter into a digital image signal through the photoelectric conversion circuit and the A/D conversion circuit and temporarily stores the image to be inspected obtained by performing image processing, The processing device compares the standard image data stored in the standard storage device with the image data to be inspected stored in the temporary storage device according to the control program stored in the ROM, and determines the image data to be inspected. A pattern defect display device characterized in that when a defect in a pattern of a pattern forming body is detected, the defect is replaced with a specified color and displayed without accessing a memory that stores a specified color code. .