JPH0472711A - Exposure condition setting method and device - Google Patents

Abstract

PURPOSE:To contrive accomplishment of quickness and stabilization of setting of conditions of pattern exposure by a method wherein the pattern density of the mask to be evaluated is measured, the relation between the pattern density and the smallest pattern size is obtained from a data bank, and the optimum exposure quantity in a exposing process using a mask to be evaluated for a semiconductor substrate, is set. CONSTITUTION:A mask pattern region 1 is formed into a patternless blank region, the transmitted light of the reference mask 3, on which the circumferential part of a mask pattern region 1 is covered by a screening film 2, is received by a photosensor 4, and ratio (S1/S0) of the quantity of received light (S0) of the photosensor 4 and the quantity of received light (S1) of the mask 5 to be evaluated is computed based on the quantity of received light (S0) of the photosensor 4, the optimum quantity of exposure of the mask to be evaluated 18 set by verifying to the exposure data in which at least one of resist type, resist film thickness, pattern type, minimum pattern size and pattern density, which are stored in a data bank in advance.

Description

[Detailed description of the invention] 〔overview〕 The present invention relates to a method for setting exposure conditions for an exposure apparatus.

The goal is to speed up and stabilize exposure condition settings.

■Make the mask pattern area a patternless blank area,
A photosensor receives transmitted light through a reference mask whose peripheral edge of the mask pattern area is covered with a shielding film.

Using the amount of light received by the photosensor (S0) as a reference, the ratio (St/SO) to the amount of light received by the mask to be evaluated (S, ) is calculated.

The optimal exposure amount for the mask to be evaluated is set by comparing with exposure data stored in advance in a data bank, including at least one of resist type, resist film thickness, pattern type, minimum pattern size, and pattern density.

■It has a detection section that measures pattern density, a data bank that stores exposure data, and a calculation section that takes in the data of the detection section and the data bank and sets the optimal exposure amount;
The detection unit detects the amount of light transmitted through the mask to be evaluated using a photo sensor.

It is converted into a digital value by a DA converter, and the data bank stores the optimal exposure amount calculated from multiple reference patterns that combine resist type, resist film thickness, pattern type, minimum pattern, and pattern density. The calculation unit obtains the ratio (St/S0) of the received light amount (Sl) and the received light amount of the reference mask (S0), and compares it with the data in the data bank to determine the optimal exposure amount for the mask to be evaluated. Configure to set.

[Industrial application field]

The present invention relates to a method for setting exposure conditions for an exposure apparatus.

Higher integration and miniaturization of LSI semiconductor device patterns are
As technology continues to advance, the importance of controlling pattern line width is increasing.

[Conventional technology]

FIG. 4 is an explanatory diagram of a conventional example.

In the figure, 21 is a uniform illumination light source, and 22 is a reticle.

23 is a platen, 24 is an XY stage, 25 is a focusing lens group, 26 is a column, 27 is a reduction lens, 28 is a test mask, 29 is an XY stage, 30 is a vibration isolation table, 31
is the irradiation light.

The above line width control is performed by performing test exposure on a test mask 28 coated with a resist film for each reticle 22 or master mask to be used using the exposure apparatus shown in FIG. 4, and then determining the exposure conditions. I am using a method.

The number of man-hours required to perform test exposure for each sheet increases.

■Because it takes time to get the exposure results, the turnaround time from development to mass production becomes long, resulting in delays in mass production and commercialization.

■Unable to respond quickly to changes in process parameters such as exposure, development, and etching, resulting in a decrease in 1-dimensional accuracy.
As a result, the yield of 9 was unstable.

leading to a decline.

I had problems such as.

・The exposure amount is determined by comparing the relationship between the minimum dimension determined through testing and the exposure amount.

In view of one or more points, the present invention is provided for the purpose of speeding up and stabilizing the setting of pattern exposure conditions.

[Means to solve the problem]

FIG. 1 shows an optimal exposure calculation system of the present invention, and FIG. 2 shows a reference mask and a reference pattern used in the present invention.

In the figure, 1 is a mask pattern area, 2 is a shielding film, and 3 is a mask pattern area.
4 is a reference mask, 4 is a photo sensor, and 5 is a target [Problem to be solved by the invention] LSI manufacturing technology is constantly being developed and advanced.

Responding quickly to improvements in this technology will contribute to improving and stabilizing commercialization 2 quality, and is an important issue in reducing manufacturing costs.

In setting the pattern exposure conditions, the means for evaluating pattern density and the results are evaluated in advance. 11 is a platen, 12 is an XY stage, and 13 is a column.

14 is a focusing lens group, 15 is a reduction lens, 16 is irradiation light, 17 is a received light amount meter, 18 is a memory, 19 is a computer, and 20 is a typewriter.

In the present invention, first, as a means for evaluating the pattern density of the mask 5 to be evaluated, the exposure area in which the mask pattern is formed is transparent, that is, patternless, and its peripheral portion is covered with a shielding film 2 made of chrome or the like. A reference mask (including a reticle) 3 is prepared and compared with the mask to be evaluated using the exposure apparatus shown in FIG. 1, and the amount of light received from the photosensor 4 is measured.

Then, the optimum exposure amount is set based on the minimum pattern dimension of the mask 5 to be evaluated.

That is, one object of the present invention is to make the mask pattern area 1 a patternless blank area, to receive transmitted light of a reference mask 3 in which the peripheral edge of the mask pattern area 1 is covered with a shielding film 2 by a photosensor 4; The ratio (St/
s0) in advance.

Resist type and resist film thickness in data panchromatic.

By comparing at least one of pattern type, minimum pattern size, and pattern density with stored exposure data, and setting the optimum exposure amount for the mask to be evaluated.

It also has a detecting section 7 that measures pattern density, a data panchromatic unit that stores exposure data, and a calculating section 8 that takes in the detecting section 7 and the data panchromatic data and sets the optimum exposure amount.

The detection section 7 detects the amount of light received passing through the mask 5 to be evaluated using the photo sensor 4, and converts it into a digital value using the DA converter 9.

The data panchromatic information includes resist type and resist film thickness.

It stores the optimum exposure amount calculated from a plurality of reference patterns that are a combination of pattern type, minimum pattern, and pattern density.

The calculation unit 8 calculates the ratio (S1/S0) of the received light amount (Sl) and the received light amount (S0) of the reference mask 3, and compares it with the data of the data panchromatic to determine the optimum exposure amount of the mask 5 to be evaluated. This is achieved by using an exposure condition setting device that is characterized by setting the exposure conditions.

[Effect]

In the present invention, as described above, the pattern density of the mask to be evaluated is measured, the relationship with the minimum pattern dimension is obtained from a data bank, and the optimum exposure amount in the exposure process using the mask to be evaluated for semiconductor substrates is calculated. Can be set.

〔Example〕

FIG. 1 is a system for calculating the optimum exposure dose of the present invention, FIG. 2 is a reference mask and reference pattern used in the present invention, and FIG. 3 is a diagram showing the relationship between pattern density/minimum dimension and optimum exposure dose.

An embodiment of the present invention will be described.

First, as shown in FIG. 2 (S), a reference mask is created in which the mask pattern area 1 is a patternless blank area and the peripheral edge of the mask pattern area is covered with a shielding film 2 made of a sputtered chromium film. death.

It is loaded into the exposure apparatus shown in FIG. 1, and the transmitted light of 1 (10%) of the mask pattern area of the reference mask is received by a photosensor having a light receiving area of 20 - 1 corner.

On the other hand, the minimum dimension pattern is set within the mask pattern area by 0.
Embed in the range of 2 to 2 μm, and create a plurality of reference patterns 10 with the pattern area density in the mask pattern area from coarse near zero to 1 (close to 10% density), and the minimum pattern is patterned as designed. The optimum exposure amount is determined, and the data is collected and stored in data panchromatic storage.

For example, as shown in FIGS. 2(A) to 2(D).

Using two types of minimum patterns, 0.5 μm square and 2 μm square, and using a total of 4 types of reference patterns with respective pattern densities of 5% and 75%, the exposure apparatus is applied to a semiconductor substrate such as silicon coated with resist. After development, the pattern is inspected using SEM, etc., and the type of resist film used, film thickness, etching conditions (reflectance differs depending on whether it is an insulator or metal), pattern type (open window, etc.) The optimum exposure amount is set by taking into account the process conditions such as (the brightness differs depending on the electrode formation), and the optimum exposure amount is set based on the balance between pattern density and minimum dimension under the process conditions as shown in Figure 3. In this way, a large amount of data can be accumulated.

Next, in the detecting section 7, the analog amount of light received by the photosensor 4 of the mask 5 to be processed is summarized into a digital amount by the converter 9.

This amount is stored in the memory 18 in the calculation section.

The computer 19 calculates the pattern density of the mask to be processed 5 by comparing it with the amount of received light S0 of the substrate mask measured in advance.

Once the pattern density has been calculated, the minimum pattern dimensions and process conditions are known from the design information of the mask to be processed, so the data for the corresponding conditions is retrieved from the data stored in the data bank and the optimum exposure amount is determined. The data is automatically output from the typewriter 20.

In this way, conventionally, a mask to be processed is used.

Instead of previously determining the exposure conditions by exposing and developing a semiconductor substrate for testing and observing the pattern, the method, device, and system of the present invention enables the setting of the exposure amount in a short time. It is now possible to do this.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to shorten the setting time for process conditions such as exposure time, and the time required for setting process conditions such as exposure time can be reduced from more than 1 hour to 10 minutes or less.

Along with this, the present invention can also be applied to simulations when changing the type of resist or process conditions, reducing process development time and setting time for process conditions such as reactive dry etching. As a result, the yield was increased by 5% due to the precision amplifier setting conditions.

[Brief explanation of drawings]

FIG. 1 shows the optimum exposure amount calculation system of the present invention. FIG. 2 shows the reference mask and reference pattern used in the present invention. Figure 3 is a diagram showing the relationship between pattern density/minimum dimension and optimum exposure amount. FIG. 4 is an explanatory diagram of a conventional example. In fig. ■ is the mask pattern area. 2 is a shielding film, 3 is a reference mask 24 is a photo sensor, 5 is a mask to be evaluated 6 is a data bank, 7
The detection unit 12 is an XY stage, and the column 14 is a focusing lens group. 15 is a reduction lens, 16 is an irradiation light 17 is a received light amount meter, 18 is a memory 19 is a computer, 20 is a typewriter Mufaji 0 minimum front light 1 calculation system No. 1 Mask Bi reference pattern 2nd
[21 S Minimum dimension Rem (ILm) D Explanatory diagram of the conventional example 'y] + Box

Claims (1)

[Claims] 1) The mask pattern area (1) is a patternless blank area, and the peripheral edge of the mask pattern area (1) is covered with a shielding film (
The transmitted light of the reference mask (3) covered with the photo sensor (
4), and the amount of light received by the photosensor (4) (S_0)
Based on the amount of light received by the mask to be evaluated (5) (S_1)
The ratio (S_1/S_0) of An exposure condition setting method characterized by setting an optimum exposure amount for the mask to be evaluated (5). 2) A detection section (7) that measures pattern density, a data bank (6) that stores exposure data, and a calculation section that takes in the data of the detection section (7) and the data bank (6) and sets the optimum exposure amount. (8), the detection unit (7) detects the amount of light received passing through the mask to be evaluated (5) using a photosensor (4), and converts it into a digital value using a DA converter (9). The data bank (6) stores the optimum exposure amount calculated from a plurality of reference patterns (10) that combine resist type, resist film thickness, pattern type, minimum pattern dimension, and pattern density. The calculation unit (8) calculates the ratio (S_1/S_0) of the amount of received light (S_1) and the amount of received light (S_0) of the reference mask (3), and compares it with the data in the data bank (6) to determine the amount of light received. An exposure condition setting device characterized by setting an optimum exposure amount of a mask to be evaluated (5).