JPS60227258A - Production of photomask - Google Patents

Abstract

PURPOSE:To enable direct reading of dimensional accuracy after formation of a pattern in a process for manufacturing a photomask by the microscope alone without using a micrometer by forming patterns for dimensional inspaection on the photomask. CONSTITUTION:The mask layer on a mask substrate is subjected to a photoetching treatment by using an original mask plate having the plural inspection patterns having the widths increasing or decreasing gradually at known sizes or a direct exposing means controlled by pattern information including the information on said inspection patterns by which the mask layer is made into a pattern having a prescribed shape. Said patterns for dimensional inspection are juxtaposed with rectangular patterns 3 having, for example, successively increasing widths W, 2W, 3W, 4W, 5W and rectangular drop-out patterns 4 having successively increasing widths as well as patterns 5 from figures 1 to 5 in a way that the respective patterns can be recognized in accordance with the widths and positions of the rectangular patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a fine pattern photomask, which makes it possible to directly read mask dimensional accuracy in a mask manufacturing process using a dimensional inspection pattern.

Structures of conventional examples and their problems In recent years, with the progress of technology such as VLSI, photomasks with fine patterns of one order of magnitude or less have been formed. In addition, as a result, it has become extremely important to obtain information regarding the degree of dimensional accuracy of patterns formed in the photomask manufacturing process when forming fine patterns.

Conventionally, among the patterns formed on a photomask as shown in FIG. The dimensional accuracy of the pattern was confirmed by measuring it. however,
With this method, a measuring device such as a micrometer must be used each time a photomask is manufactured, making the manufacturing process complicated.Moreover, mechanical accuracy becomes a problem when the maximum deviation value of dimensional variation is less than 1 μm. There was a problem in that it was not possible to accurately measure the actual dimensions. Note that the shaded area in FIG. 1 indicates the opaque area of the photomask.

Purpose of the Invention The present invention provides a photomask manufacturing method that can eliminate the above-mentioned inconveniences, that is, a photomask in which the dimensional accuracy after pattern formation in the photomask manufacturing process can be directly read using a microscope without using a micrometer. The present invention provides a method for manufacturing.

Structure of the Invention The photomask manufacturing method of the present invention provides a mask layer on a mask substrate having a mask original plate having a plurality of inspection patterns whose widths increase or decrease sequentially with known dimensions, or pattern information including the inspection pattern information. In this method, the mask layer is patterned into a predetermined shape by photoetching using direct exposure means controlled by the method.

According to this method, an inspection pattern that disappears among inspection patterns whose dimensions are known and is formed on a photomask,
Furthermore, the amount of etching can be determined based on confirmation of the test pattern located next to the disappeared test pattern.

DESCRIPTION OF EMBODIMENTS An embodiment of the photomask manufacturing method of the present invention will be described with reference to FIG. FIG. 2 is a diagram showing an example of a dimension inspection pattern ideally formed without side etching on the photomask of the present invention.

This pattern has widths of W, 2W, aw, and 4W.

Rectangular pattern 3 with widths of 6W and 2W, 3
A hollow rectangular pattern 4 which is expanded sequentially as W, 4W, and 5W, and patterns 6 with numbers 1 to 5 are juxtaposed so that each pattern can be recognized in accordance with the width and position of the rectangular pattern. The reason why the inspection pattern is a rectangle with parallel sides is that it has the feature that the average amount of etching can be seen. Note that the diagonal lines in Figures 2 to 4 do not indicate transparent and opaque areas of the photomask, but indicate areas that are recognized to be usable for both positive and negative resist masks. It is.

The value of W depends on the accuracy of the equipment or materials used in the photomask manufacturing process, but is preferably 0.1 to 0.3 μm.

The reason why the rectangular pattern 3 and the inverted rectangular pattern 4 with hollow holes are juxtaposed is so that it can be used both when etching a rectangular pattern and when etching the periphery of a rectangular pattern to produce a photomask. This is to do so. However, if you know the condition of the mask you are using,
Either pattern can be used.

This dimension inspection pattern is manufactured on a photomask,
Moreover, if the area recognized at the time of manufacturing is etched to be thinner by W, for example, then rectangles with widths W and 2W corresponding to numbers 1 and 2 of the inspection rectangular pattern 3 formed on the photomask will be formed. The pattern disappears and the number 3
, 4.5, the widths of the rectangular patterns are 2W, 2W, and 3W, respectively, which are narrower by 2W. On the other hand, the width of each of the hollowed out inspection rectangular patterns 4 is 2W wider than the original pattern width, and the pattern widths corresponding to numbers 1 to 5 are 3W to 7W.

On the other hand, if the recognized area is etched to be thicker by W, for example, the rectangular patterns corresponding to numbers 1 and 2 and having widths W and 2W disappear, and number 3 is removed. , 4.6, the width of each rectangular pattern is narrower than the original pattern width by 2W.
, 2W, and 3W. Moreover, the width of the rectangular pattern 3 is 2W wider than the original pattern width, corresponding to numbers 1 to 5, and becomes 3W to 7W.

As described above, in the manufacturing method of the 7-oto mask of the present invention, the amount of etching can be determined by observing the disappearance state of the rectangular pattern forming the pattern for dimension inspection, and the pattern width can be visually observed with a microscope without measuring with a micrometer. It is possible to read the fine pattern accuracy with just a single measurement, and it is possible to judge whether mask production is good or bad.

In addition, as another embodiment of the present invention, a rectangular pattern 6 with hollowed-out numbers as shown in FIG. 3 and a width of W, 2W, 3W, 4W,
It is also possible to create a pattern in which sW and inspection pattern 7 that are sequentially changed are juxtaposed (upper side of FIG. 3).

It is also possible to create a pattern in which the recognition area is reversed (lower side of Figure 3).

In the case of this pattern, the position of the inspection pattern to be erased by etching can be determined even if there is no corresponding number pattern, and the recognition of the inspection pattern and number pattern used to measure etching accuracy is reversed. Therefore, even if the test pattern for measuring etching accuracy is erased, the number pattern always remains and is easy to distinguish.

Further, as another embodiment of the present invention, a ring pattern may be used in which the width of the test pattern is varied in order to check the etching accuracy in all directions, as shown in FIG.

All the test patterns described above have the width between two parallel sides changed five times from W to 5W, but the invention is not limited to this.

As described in detail of the invention, according to the method for manufacturing a photomask with an inspection pattern of the present invention, the dimensional accuracy after pattern formation can be directly read by simply visually observing it with a microscope, without measuring the dimensional accuracy with a micrometer. This makes it easy to judge whether mask production is good or bad. Also, according to this pattern, for example,
If the pattern is etched by W, the dimensional accuracy can be detected when the pattern changes by 2W, so it can be read with twice the accuracy.

[Brief explanation of drawings]

1... Opaque rectangular pattern, 2... Transparent rectangular pattern, 3... Rectangular pattern/, 4...
...Rectangular pattern with hollow holes, 6... Number pattern, 6... Rectangular pattern with hollow numbers, 7
...Parallel side, 8...Ring. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
figure

Claims (9)

[Claims] (1) Using a mask original plate having a plurality of inspection patterns whose widths sequentially increase or decrease with known dimensions on a mask layer on a mask substrate, or a direct exposure means controlled by pattern information including the inspection pattern information. 1. A method for manufacturing a photomask, characterized in that the mask layer is patterned into a predetermined shape by subjecting the mask layer to a photo-etching process. (2) The method for manufacturing a photomask according to claim 1, wherein the mask original plate has a plurality of independent inspection patterns. (3) The method for manufacturing a photomask according to claim 1, wherein the mask original plate has a plurality of continuous inspection patterns. (4) The method for manufacturing a photomask according to claim 1, wherein the direct exposure means is controlled by pattern information including a plurality of independent inspection pattern information. (5) The method for manufacturing a photomask according to claim 1, wherein the direct exposure means is controlled by pattern information including information on a plurality of continuous inspection patterns. (6) The method for manufacturing a photomask according to claim 1, wherein the mask original plate has an inspection pattern in which two opposing sides are parallel. (7) The method for manufacturing a photomask according to claim 1, wherein the direct exposure means is controlled by pattern information including inspection pattern information in which two opposing sides are parallel. (8) The method for manufacturing a photomask according to claim 1, wherein the mask original plate used has a pattern of symbols or numbers arranged near the inspection pattern. (9) The direct exposure means is controlled by pattern information including an inspection pattern and pattern information of symbols or numbers located in the vicinity of the inspection pattern.
2. Method for manufacturing a photomask as described in section.