JPH0464219A - Charged particle beam drawing device - Google Patents

Abstract

PURPOSE:To form an article to be machined with high accuracy by comparing a pattern data used at a time when a previously machined structure is drawn and an afterward drawn pattern data, extracting a feature point such as overlap ping and varying the conditions of drawing on the basis of the feature point. CONSTITUTION:A pattern data storage section 1 is composed of a memory 1a, in which a pattern data (hereinafter called a foundation data) regarding a previously machined structure is stored, and a memory 1b, in which a pattern data (hereinafter called a machining data) used when an article to be machined is machined is stored. Extracting feature points 5 regarding items having effects on the results of drawing such as the mutual overlapping of graphics, adjacent relationship, etc., are obtained on the basis of two data output from the storage section 1 and conditions 3 in a comparator 2. A drawing device 6 is controlled according to predetermined drawing conditions on the basis of the extracting feature points 5 and machining data stored in the memory 1b, and an article to be machined 7 is drawn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a writing technique used in semiconductor manufacturing, and particularly to a technique that is effective when used for writing using a charged particle beam. .

[Conventional technology]

Various methods have been used to expose a wafer to light, one of which is direct writing using an electron beam. This method has the advantage of being able to form fine patterns without using a photomask, and is suitable for manufacturing high-density packaging semiconductor devices.

This type of device is described, for example, in Japanese Patent Application Laid-Open No. 53-50978 and Japanese Patent Application Laid-open No. 63-285933. Tokukai Showa 6
No. 3-285933 discloses a configuration in which the irradiation amount is changed depending on the size of the electron beam used for drawing in order to prevent deterioration of pattern formation accuracy in electron beam drawing,
No. 285,933 discloses a method of dividing a pattern into a plurality of regions and writing the pattern using a thick beam at the center and a thin beam at the outer periphery, thereby ensuring writing accuracy while maintaining throughput.

By the way, the present inventor has discovered that the structural part (
We investigated the deterioration of pattern shape accuracy due to differences in electron reflection depending on the shape or material.

The following are the techniques studied by the present inventor, and the outline thereof is as follows.

In other words, this type of device irradiates an electron beam emitted from an electron gun onto a wafer through a plurality of shaping and deflecting means.
The structure is such that drawing is performed by a combination of this deflection scanning and driving of the XY stage on which the wafer is placed.

[Problem to be solved by the invention]

However, conventional direct drawing devices such as the one mentioned above
It is assumed that the surface of the processed part is flat, and if a structure has already been formed on the processed part, for example, due to the difference in the number of reflected electrons between areas where heavy metals are present and where heavy metals are not present. , a difference occurs in the exposed area of the resist, resulting in a difference in size after development.

Additionally, if there is a step in the processed area, there will be a difference in the resist film thickness across the step, a difference in the focus of the electron beam, and a difference in the photosensitive state of the resist, resulting in deterioration of the pattern shape. was discovered by the present inventor.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide a technique that can form a pattern with high precision even when a structure has already been formed on a processed part.

The above objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

That is, it is a charged particle beam drawing apparatus that draws a figure on an already processed surface of a workpiece using a charged particle beam,
A base data storage means for storing the figure data used in the processing as base data, processing data as figure data to be applied to the already machined surface from now on, and base data read from the base data storage means to store each figure. The apparatus is configured to include feature point extraction means for extracting overlapping portions or adjacent portions, and control means for changing exposure conditions based on the extraction results by the feature point extraction means.

[Effect]

According to the above-mentioned means, feature points such as overlap are extracted by comparing the pattern data used when drawing a structure that has already been processed and the pattern data to be drawn from now on, and based on this extraction result. to change the drawing conditions.

Thereby, writing can be performed under optimal writing conditions, and changes in pattern dimensions and resist film thickness due to differences in underlying material and step shape can be canceled out, and pattern formation can be performed with high precision.

〔Example〕

FIG. 1 is a system diagram showing an embodiment of a charged particle beam lithography apparatus according to the present invention.

The pattern data storage unit 1 includes a memory 1a serving as a base data storage means in which pattern data (hereinafter referred to as base data) regarding structures that have already been processed is stored, and pattern data to be used when processing the workpiece from now on. It is composed of a memory lb in which (hereinafter referred to as processed data) is stored.

A comparator 2 (feature point extraction means) is connected to the pattern data storage section 1, and a comparison is made with a predetermined condition 3 (information regarding the degree of influence that should be taken into consideration when performing a drawing operation).

A control circuit 4 (control means) is connected to the comparator 2, and controls a drawing device 6 to be controlled based on extracted feature points 5 and processed data output from the comparator 2. A workpiece 7 is set in the drawing device 6 .

The comparator 2 extracts items that affect the drawing result, such as overlap between figures and adjacency relationships, based on the two data (base data and processed data) output from the pattern data storage unit 1 and condition 3. Find feature point 5. The extracted feature points 5 and the memory 1b for storing pattern data 81
The drawing device 6 is controlled according to predetermined drawing conditions based on the processing data stored in the workpiece 7.
Draw on.

Note that in this embodiment, feature points are extracted by the drawing device, but the present invention is not limited to this. For example, the same result can be obtained even if the host computer 1 adds information to the pattern data itself 1. .

FIG. 2 is an explanatory diagram showing an example of conditions for feature point extraction.

Here, an example is shown in which a location where base data and processed data overlap is set as a feature point. This condition is, for example,
This is the case, for example, when there is a heavy metal partially in the base of the workpiece 7.

In FIG. 2, processed data 8, 9, and 10 all have the same dimensions, but processed data 9 overlaps base data 11. Therefore, it is necessary to distinguish it from the processed data 8 and 10 that do not overlap. Here, processing data 9
are extracted as feature points (which are said to overlap with the base data 11).

Then, the control circuit 4 performs writing under conditions different from the processing data 8 and 9 (for example, changing the irradiation amount or beam size).

For example, if the drawing size when there is a heavy metal on the base is Ll and the drawing size when there is nothing on the base is L2, then the drawing conditions in this case are changed so that <L2.

FIG. 3 is an explanatory diagram showing another example of conditions for feature point extraction.

This example is a case where processed data 12 intersects base data 11. In this case, the intersections overlap, and the processed data 12 is changed to the processed data 13. as shown in FIG.
It is divided into three parts: 14.15. Among these, base data 1
The processed data 14 that overlaps with the processed data 14 is extracted as a feature point, and is drawn under different drawing conditions from the processed data 13, the processed data 15, and the processed data 14 that do not overlap.

In the above description, the extraction condition is that the base data and processed data overlap, but the extraction condition is not only overlap, but also adjacency within a certain distance.

Above, the invention made by the present inventor has been specifically explained based on Examples, but it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. stomach.

For example, in the above embodiments, an example of a writing apparatus using an electron beam is shown, but it is also possible to apply the present invention to any apparatus using a charged particle beam, such as one using an ion beam.

〔Effect of the invention〕

Among the inventions disclosed in this application, the effects obtained by typical inventions are briefly explained below.

That is, it is a charged particle beam drawing device that draws a figure on an already processed surface of a workpiece using a charged particle beam,
A base data storage means for storing the figure data used in the processing as base data, processing data as figure data to be applied to the already machined surface from now on, and base data read from the base data storage means to create each figure. Since feature point extraction means for extracting overlapping or adjacent parts and control means for changing exposure conditions based on the extraction results by the feature point extraction means are provided, patterns due to differences in base material or step shape are provided. Changes in dimensions and resist film thickness can be canceled out, and pattern formation can be performed with high precision.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing one embodiment of a charged particle beam lithography apparatus according to the present invention, Fig. 2 is an explanatory diagram showing an example of one condition for feature point extraction, and Fig. 3 is an explanatory diagram showing an example of one condition for feature point extraction. FIG. 4 is an explanatory diagram showing an example of the conditions of FIG. 3. FIG. 1... Pattern data storage section, 1a... Memory, 1
b...Memory, 2...Comparator, 3...Condition, 4.
... Control circuit, 5... Extracted feature reading/drawing device, - Workpiece, 8゜9゜10゜・Processing data, ... Base data, 13゜14゜・Processing data. Figure 13゜14゜15: Processing data

Claims (1)

[Scope of Claims] 1. A charged particle beam drawing device that draws a figure on an already machined surface of a workpiece using a charged particle beam, wherein the figure data used during said processing is saved as base data. and feature point extraction means for extracting characteristic portions between each figure based on processing data as figure data to be applied to the already processed surface and base data read from the base data storage means. A charged particle beam drawing apparatus comprising: and a control means for changing exposure conditions based on the extraction result by the feature point extraction means. 2. The charged particle beam lithography apparatus according to claim 1, wherein the feature points are extracted from overlapping portions or adjacent portions of figures. 3. The charged particle beam lithography apparatus according to claim 1, wherein the exposure condition is a beam irradiation amount or a beam size.