JP3747577B2 - Device layout design method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a layout design method using a CAD (Computer Aided Design) system, and more particularly to a device layout design method by multiple exposures.
[0002]
[Prior art]
With the development of high-definition and large-screen devices such as liquid crystal display panels, the device design is used in each manufacturing process in addition to screen configuration patterns in the product area that occupies most of the substrate. Therefore, it is necessary to form a large number of patterns including alignment marks or the like in a minute area (peripheral area) surrounding the product area with high accuracy, and the design of the layout has become complicated.
[0003]
Conventionally, in the CAD system used for layout design, the design of the product area has been the center, and in the peripheral area, the correspondence between the pattern displayed on the CAD screen and the film formation pattern on the actual device substrate Was not necessarily considered.
[0004]
In the CAD system targeted here, only the pattern of the portion remaining on the substrate after the thin film is exposed and etched in each step described below as an example of device manufacture is displayed on the CAD screen. An unexposed area, that is, a peripheral area surrounding the product area is not displayed.
[0005]
In general, the manufacture of devices such as liquid crystal display panels uses a transparent glass plate as a substrate, forms various thin films using means such as sputtering and CVD on it, and photosensitive to form fine patterns on the thin film. Through each step of agent coating, exposure, etching, etc., sequentially form a pixel array of a display unit that meets the specifications required for the product, a transistor array such as a TFT (Thin Film Transistor), and its electrodes and electrode terminal leads. Is going by. The reticle used in this exposure process is a factor that determines the production yield of the product, so high accuracy is required, and a necessary pattern is formed on a transparent glass substrate on which a light-shielding chromium or other metal thin film is formed. It is manufactured by an exposure and etching process.
[0006]
The pattern of the region to be the product part is configured using a plurality of types of reticles. The reticle is prepared for production according to the target product specifications using a pattern generator or the like separately for each process.
[0007]
As described above, in order to cope with the increase in size and size of the screen, the layout of the device is configured by combining multiple types of reticles for each process, and the entire device is shot with multiple shots (exposure) using a stepper. Form.
[0008]
For example, in a liquid crystal display panel device manufacturing, a reticle having a pattern for pixel configuration, for transistor configuration, and more specifically for gate, gate insulating film, semiconductor film, drain, source configuration and electrode configuration, as different patterns for each process. And all types of designs require multiple types of design.
[0009]
In actual product manufacturing, a gate metal film is formed as a first layer (layer), then a gate pattern is formed using a gate mask, then a gate insulating film is formed as a second layer, and gate insulation is performed. Layers are formed so as to form a film pattern, and after sequentially forming necessary films, a pattern is formed using a reticle necessary for the process.
[0010]
In general, the type and number of reticles increase with the number of layers, but the positional relationship of all the reticles used in each process needs to be accurately matched.
Therefore, in each process, for alignment between layers and the manufacturing equipment used in each process and devices such as glass substrates in the peripheral area outside the product area formed using the reticle In addition, many alignment mark patterns are formed, and alignment is performed in accordance therewith. In addition to these marks, various mark patterns used for other purposes such as inspection may be formed in the peripheral area.
[0011]
These patterns are also formed by exposure and etching processes as in the product region. This peripheral area is separated from the product area when it is no longer needed for manufacturing.
When forming a device pattern with a stepper using a reticle, it takes a long time to expose the entire device, so the product area is conventionally exposed with a stepper, but the entire peripheral area is not exposed. By limiting the exposure to only the partial areas necessary for forming alignment marks and the like, the throughput was shortened.
[0012]
However, in this case, even though the images look the same on the CAD screen, the actual device substrate image may be different because the display contents are different between the product area and the peripheral area. That is, in the product area, the metal pattern part formed through the exposure and etching process is displayed and the part without the pattern is not displayed, whereas in the peripheral area, most of the part is unexposed, so it is actually Not displayed despite the presence of a metal film. Further, even if a metal film pattern such as an alignment mark exists in a partial area of a certain layer, it may overlap with the metal film of another layer and may not be recognized on the CAD screen.
[0013]
For this reason, a design error due to misrecognition has occurred, or work efficiency has been reduced.
[0014]
[Problems to be solved by the invention]
Therefore, the present invention provides a device design method in which the display on the CAD screen and the image of the presence or absence of the metal pattern on the actual device substrate correspond to each other so that the design error due to the misrecognition of the design worker can be eliminated and the work efficiency can be improved. The purpose is to provide.
[0015]
As described above, the product area corresponds to the reticle pattern on the CAD screen, but the peripheral area is out of the exposure area by the product reticle, so that it is an unexposed area and is not displayed on the CAD screen. As with the product area, the presence or absence of metal could not be clearly grasped. That is, whether or not the metal remains or has been removed after the etching process is not displayed on the CAD screen although this portion is important for the formation of alignment marks and the like. For this reason, the design operator made a judgment on the overlapping (interference) state between the reticle used in different manufacturing processes and the layer of the film to be manufactured actually manufactured using the peripheral region.
[0016]
Therefore, when examining the overlay status of reticles used in each manufacturing process, etc., the peripheral area that is not displayed on the screen is actually metal in one of the manufactured film layers to be manufactured. Even if it exists, it cannot be distinguished whether it is not displayed because it is an unexposed area, or whether it is not displayed because there is no actual metal, and this has caused erroneous recognition in design work.
[0017]
The present invention provides a layout design method for a device that always displays the state where the metal remains on the unexposed area in the peripheral area where the metal remains, on the CAD screen.
[0018]
[Means for Solving the Problems]
The problem described above is to separate the exposure area by the reticle pattern, which is the product area, from the peripheral area, which is the non-exposure area that surrounds the product area, and recognize that part according to the shape of the peripheral area. This can be solved by generating display graphic data for facilitating the display, composing display data for the entire substrate with the data and device data as a product area, and displaying the display data on a CAD screen.
[0019]
The display pattern generated as the graphic data is added with a pattern or the like in the fill pattern setting on the CAD system. If this pattern achieves the purpose of making it easy to distinguish from other areas, there is no particular emphasis on shading or diagonal lines.
[0020]
In the example of the liquid crystal display panel, when the entire glass substrate is displayed, the pattern added in the setting of the fill pattern is displayed on the CAD screen where the pattern in the product area and the metal in the unexposed area are formed. .
[0021]
By doing this, when the exposure work of the product area of each layer is advanced by multiple exposures using multiple types of multiple reticles, the peripheral area of each layer is visualized on the CAD screen, Since the exposure position of alignment marks and the like can be visually confirmed, layout design can be performed very efficiently.
[0022]
Thus, in designing a device using CAD, if the substrate is displayed with the above-described screen configuration, the presence or absence of the metal film in the peripheral region in the actual process is displayed on the CAD screen in the same manner as in the product region, and the overlap between layers is displayed. The state becomes clear.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 are diagrams for explaining the implementation according to the present invention.
The entire substrate to be exposed is displayed on the CAD screen, and the contour representing the outer periphery is defined as x in FIG. A product region on the substrate to be exposed is configured by arranging a reticle pattern that matches a target specification. For example, when the reticle pattern is composed of four types of patterns a, b, c, and d, the contour y representing the outermost periphery of these reticle patterns is first extracted in the CAD system. A region z representing the shape of the peripheral region is created by graphic logic operation of y and the outer periphery x of the substrate. FIG. 1B shows the region of z and the outermost periphery y. In order to identify and visualize the z region, a setting is made to add a fill pattern on the CAD system. In the figure, the region is indicated by hatching. Thereafter, the peripheral area z in which the fill pattern is set and the product area constituted by the data of the reticle patterns a, b, c, and d are combined to display the entire substrate on the CAD screen.
[0024]
FIG. 1C shows the display state of the entire substrate. On the newly displayed CAD screen, the state of the peripheral area that has not been displayed conventionally is visualized, and it is easy to confirm the presence or absence of metal.
[0025]
FIG. 2A shows an example of a screen displaying marks for alignment or the like by a conventional display method. As shown in this figure, the metal was present on the substrate only in the peripheral area where the mark was formed. FIG. 2B is a display example according to this method. The presence of metal in the surrounding area is indicated by shading, etc., and since there is no shading in part and no metal exists, a window is opened and inside A state in which the mark is made of metal is shown.
[0026]
FIG. 2 (c) shows that a metal exists in a layer different from FIG. 2 (b) by shading, etc., and shows a state where there is a portion where there is no shading and no metal exists due to opening of the window. ing.
[0027]
When figures (b) and (c) with different layers are superimposed on the CAD screen, patterns overlapping with e, f, g, and h are displayed in the reticle areas a, b, c, and d, respectively. Area marks can be displayed in a state where they do not necessarily overlap by opening a window. This makes it easier to work with all layers overlaid when the number of layers is large, thereby improving efficiency.
[0028]
【The invention's effect】
According to the present invention, an unexposed area in a peripheral area that has not been conventionally displayed on a CAD screen can be displayed in correspondence with an actual state. As a result, according to the present invention, the design operator can design the layout of the device without erroneously recognizing the actual process on the CAD screen, and the design efficiency can be greatly improved.
[0029]
Therefore, the present invention greatly contributes to device design.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a display method of the present invention. FIG. 2 is a display example of a display method of the present invention.
a, b, c, d Four types of reticle patterns e, f, g, h Four types of reticle patterns of other layers u Marks for alignment, etc. v Window opening for mark patterns w Display and windows such as shading Open display x Outer perimeter of substrate y Outer perimeter of reticle pattern z Peripheral area

Claims (2)

In a device layout design method for forming a device pattern on the main surface of a substrate to be exposed by multiple times of exposure using CAD,
First graphic data representing the contour of the main surface of the substrate to be exposed, second graphic data representing a product region in which the device pattern is formed on the main surface of the substrate to be exposed, and a peripheral region of the product region Generating third graphic data representing a pattern to be formed;
Generating, from the first graphic data and the second graphic data, fourth graphic data representing a region excluding the product region of the main surface of the substrate to be exposed;
An unexposed area of the area represented by the fourth graphic data is displayed in a recognizable manner, and the pattern represented by the third graphic data and the exposure pattern of the product area are represented by the fourth graphic data. And a method of designing the layout of the device, the method including a step of superimposing the display on the display of the region. 2. The device layout design method according to claim 1, wherein the area represented by the fourth graphic data is displayed as a fill pattern.

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