JPS5815936B2 - How to use the mask - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of making a mask for an integrated circuit.

Typically, to fabricate an integrated circuit, a mask is created by drawing a mask pattern on a glass or plastic substrate, and the mask is placed on the integrated circuit substrate, exposed, and etched to form diffusion holes according to mask pattern J-7. integrated circuits are realized by diffusing impurities.

One mask is used for each diffusion step, and typically six or more masks are required to fabricate an integrated circuit.

When designing a mask, the pattern is determined where each element (transistor, resistor, etc.) that makes up the integrated circuit should be placed on the mask, taking into consideration the design and manufacturing conditions. .

However, during the design process, operations such as simultaneously overlapping several mask patterns corresponding to each diffusion process and extracting only the specified mask pattern must be repeated many times, making it difficult to accurately select the optimal mask. difficult to produce.

In order to make this operation as easy as possible, it has been proposed to design a mask using a graphic display device.

Conventionally, this type of mask design apparatus is comprised of an information processing apparatus, a graphic display apparatus for displaying in one color, a photographic recording apparatus, and a light pen.

However, the graphic display device displays in one color, and the light pen used in this device can equally display all the data within the field of view of the light pen from among the data drawn by the graphic display device.
Detect that light.

For this reason, even if other diffusion process drawings are distinguished by bright lines or line types such as solid lines or dotted lines, detection with a light pen cannot distinguish them.

In other words, if data from another diffusion process drawing generates light near a certain point on the display screen of a graphic display device, that light will also be detected, making it difficult to always specify correctly with a light pen. It's flawed too.

Therefore, when attempting to correctly detect data for each diffusion process using a light pen, the procedure is to re-display only the data of the required diffusion process drawing each time, and then perform detection using the light pen. This means that both simultaneous and single displays of each diffusion process drawing will be displayed.

Repeated operations like this often become inefficient and take a huge amount of time if done many times, and depending on the skill of the individual, they may produce incorrect masks that do not meet the design and manufacturing conditions, or the design may be incorrect. Even if it is possible, it often takes a huge amount of time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for creating a mask for an integrated circuit that reduces the time required for the above-described repetitive operations and allows for efficient design.

According to the present invention, there are a step of incorporating graphical information regarding a plurality of masks into an information processing device, and a step of extracting a plurality of graphical information from the information processing device and color-coding them for each mask and drawing them on a graphic color display device. , a step of transmitting only light in a specific wavelength range corresponding to the type of mask among the patterns drawn on the graphic display device and photographically recording a light pattern caused by the transmitted light; A method for making a mask for an integrated circuit is obtained, comprising the step of obtaining a mask by baking it onto a glass substrate.

Next, the present invention will be explained with reference to the drawings.

Referring to FIG. 1, an information processing device 1 used in the present invention stores graphical information regarding a mask and a program for controlling mask design procedures, executes the program,
This is a device that processes data.

This information processing device 1 does not need to be dedicated to a mask design device for integrated circuits, and a normal electronic computer can be used.

The graphic color display device 2 is a device that draws the display data sent from the information processing device 1 in a specified color, and can simultaneously display not only letters and numbers but also mask patterns in different colors for each diffusion process. can.

The photographic recording device 4 is equipped with a filter plate 3 that transmits only light in a specific wavelength range, and records only the light that passes through the filter plate 3 out of the data displayed on the graphic color display device 2.

The light pen 6 is equipped with a filter plate 5 at its tip that transmits only light in a specific wavelength range, and among the data drawn in several colors on the graphic color display device 2, the light that passes through the filter plate 5 This is a photodetector that detects only the data and interrupts the information processing device 1 to extract data to be processed.

As the light pen 6, a photodiode or a combination of an optical fiber and a photomultiplier can be used.

A photodetector can detect not only monochromatic light but also several colors simultaneously, depending on the wavelength and intensity of the light.

Next, a method for creating a mask according to the present invention will be explained.

The information processing device 1 stores graphical information regarding the mask and a program for controlling the mask design procedure, and by executing this program, data of the diffusion process drawing is sent to the graphic color display device 2 to display the diffusion process drawing.

The graphic color display device 2 receives color specification data and display data sent from the information processing device 1,
Draws display data in the specified color.

In other words, various diffusion process drawings for integrated circuits (for bipolar integrated circuits, for insulation diffusion, emitter diffusion, base diffusion, etc.; for MO8 integrated circuits, for gate diffusion, boron diffusion, etc.) (diffusion process drawings) are simultaneously displayed on the graphic color display device 2 with different colors for each diffusion process.

The filter plate 5 is set so that only the light of the diffusion process drawing to be corrected can be detected by looking at the displayed drawing.

The light pen 6 is moved to a part of the displayed drawing to be corrected, its light is detected, and an interrupt is made to the information processing device 1 to notify the data.

The information processing device 1 corrects the data of the diffusion process drawing by adding, deleting, or replacing data according to the interrupt information from the light pen 6, and displays the corrected drawing again.

Repeat this operation to complete one of the diffusion process drawings, then set another filter plate 5 so that only the light from the other diffusion process drawing can be detected, modify that diffusion process drawing, and complete it. .

This process is repeated to complete all mask patterns.

The completed mask pattern is displayed on the graphic color display device 2, and a filter plate 3 is set to transmit the light of the diffusion process drawing to be selected, and the drawing for each diffusion process is recorded on the photographic recording device 4.

Furthermore, by using a double-printing technique, it is also possible to record in the photographic recording device 4 a drawing in which several desired diffusion drawings are superimposed.

Next, using a mask design device, once the mask pattern is determined, a mask is created.

After the mask pattern for each diffusion step recorded in the photographic recording device 4 is enlarged or reduced by photographic techniques, the pattern is exposed and developed on a glass or plastic substrate coated with a photosensitive material to form a mask.

According to this other method of manufacturing a mask, an information processing device 1 is used to operate an electron beam exposure device based on information regarding the stored mask pattern, and a photosensitive material is coated on a glass or plastic substrate. A mask can also be formed by irradiating an electron beam according to a pattern.

As is clear from the above description, according to the present invention, the mask pattern can be simultaneously displayed in different colors for each diffusion process, and a filter plate is attached to the tip of the light pen. Since only the light that passes through the mask pattern is detected, errors can be detected quickly during the mask pattern design process, and the data can be extracted in exactly the same way as when each diffusion process drawing is displayed individually. This greatly reduces the need for repeated operations such as displaying the diffusion process drawings simultaneously or extracting only the specified diffusion process drawings, and recording can be done by simply replacing the filter plate, allowing for overlapping display and extraction. It is possible to efficiently design integrated circuit masks in a short period of time without the need for such operations.Comparing the design method of the present invention with the conventional method, it is possible to design masks for integrated circuits efficiently in a short time. The time T required for designing a mask pattern in the creation method includes mask design processing time t1 in the information processing device, time t12 for data transfer from the information processing device to the graphic color display device, display time t2 on the graphic color display device, and graphic color. The total time t26 for a human to instruct the light pen to transmit the data displayed on the display device, the time tat for transmitting the data captured by the light pen to the information processing device, and the time t24 for transmitting the data to the photographic recording device. Oro as T2 t1+t12+t2+t26+t6□
+t24 can be expected.

On the other hand, in the time required to design a mask pattern using a conventional design device, in the case of an integrated circuit that requires m masks, at least τ=m2(tl+t12+t2+t2a+t
at)+mt24.

At this time, since m is usually 6 or more, the time required for design can be greatly shortened by using the method according to the present invention.

It is clear that the integrated circuit mask creation method according to the present invention can be used not only for designing a mask for the diffusion process described as an example above, but also for designing an etching mask for metal wiring. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an apparatus used in an embodiment of the present invention. 1... Information processing device, 2... Graphic color display device, 3... Light filter, 4... Photographic recording device, 5...
...Filtering plate, 6...Light pen.

Claims (1)

[Claims] 1. A step of incorporating graphical information regarding a plurality of masks into an information processing device, a step of extracting a plurality of graphical information from the information processing device and color-coding them for each mask and drawing them on a graphic color display device; A step of transmitting only light in a specific wavelength range corresponding to the type of mask among the patterns drawn on the play device and photographically recording a light pattern caused by the transmitted light;
A method for making a mask for an integrated circuit, comprising the step of: obtaining a mask by printing the photographically recorded pattern onto a lath substrate.