JP2000131823A - Semiconductor reticule mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent dielectric breakdown of a reticule with a simple structure by electrically connecting isolated patterns which constitute a metal pattern with an extra-fine pattern smaller than the resolution limit. SOLUTION: Isolated patterns 1 to 4 which constitute the metal pattern are electrically connected with an extra-fine pattern 5 smaller than the resolution limit. The extra-fine pattern 5 is formed to drain the electric charges in other metal patterns and is inserted into regions where discharge is easily caused by the edge effect such as pattern corners and narrow regions between patterns, and has the size smaller than the resolution limit. The extra-fine pattern 5 can be simultaneously formed when the other metal patterns such as a circuit pattern 1 are formed. By this method, when the pattern touches a charged reticule or a man, charged device or jig, electrostatic charges are released through the inserted pattern which connects the patterns so that no discharge is caused between the isolated patterns, and therefore, no dielectric breakdown is caused.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor reticle mask used in a photolithography process for manufacturing a semiconductor device, and more particularly to a mask capable of preventing electrostatic breakdown of a pattern.

[0002]

2. Description of the Related Art A stepper is mainly used as an exposing machine for printing a circuit on a wafer in accordance with a fine pattern of a semiconductor integrated circuit. In the stepper, a semiconductor reticle mask (hereinafter abbreviated as a reticle) having a pattern size 1 to 10 times the pattern size on the wafer is used. An electron beam exposure apparatus is mainly used for drawing a circuit pattern for producing a reticle. At this time, a reticle formed when a negative resist is used as a resist sensitive to an electron beam is as shown in FIG. There was something. That is, chrome on a transparent glass substrate,
It has a metal pattern formed of a light-shielding metal film such as chromium oxide. The metal pattern mainly includes a circuit pattern 1, an alignment pattern 2, and a scribe TEG pattern 3.
And a light-shielding pattern 4 and the like formed around them. These patterns are isolated from each other, and each isolated pattern itself usually has an isolated part or is divided into several parts.

The circuit pattern 1 is a pattern in which a relatively large metal film such as an electrode pad, a via hole, or a contact hole remains, and the alignment pattern 2 is a pattern for forming an alignment mark on a wafer (not shown). The TEG pattern 3 is a pattern for forming a test element (usually provided in a scribe line of a wafer).

The main structure of the reticle formed when a positive resist is used as the resist has a shape in which the light-shielding portion on which the metal pattern shown in FIG. 2 is adhered and the exposed transparent portion of the glass substrate are inverted.

[0005]

Since the reticle has a structure in which a metal film is formed on a glass substrate, which is an insulator, the flow of air in a clean room in which a reticle is manufactured or used, or a reticle is used. High-pressure shower washing with pure water used for washing or the like, or electrification is caused by friction with an insulating reticle carrier, a case or the like.

[0006] The charge amount may reach several KV to several tens KV. At this time, a discharge phenomenon occurs in the circuit pattern of the reticle, and a part of the pattern may be destroyed (electrostatic breakdown). . Experience has shown that electrostatic breakdown is likely to occur when the majority of the reticle is chrome or when the spacing between patterns is very narrow. In particular, it is considered that electrostatic breakdown easily occurs between large patterns, such as between a circuit pattern and a light-shielding pattern, because they become capacitors and store large electric charges. For this reason, when the trapped charges are released at one time, the corners of the pattern or between narrow patterns become a path for the charges due to the edge effect, so that the parts are destroyed.

When the above-described electrostatic breakdown occurs after the completion of the shipping inspection of the reticle, since a part of the circuit pattern is broken, a normal semiconductor integrated circuit cannot be manufactured, and the diffusion yield is greatly reduced. Cause. In order to prevent this, it is necessary to inspect the entire pattern area immediately before using the reticle, which requires a lot of man-hours.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem and to prevent electrostatic damage of a reticle with a simple structure.

[0009]

According to a first aspect of the present invention, there is provided a reticle having a glass substrate and a metal pattern formed on the glass substrate. It is characterized in that they are interconnected and electrically connected with each other in an ultrafine pattern less than the resolution limit.

The second invention is characterized in that the ultrafine pattern is formed of the same material as the metal pattern.

[0011]

With this configuration, when touching a charged reticle, or touching with a person, a charged device or a jig, static electricity escapes through an insertion pattern connecting the patterns. And no electrostatic breakdown occurs.

[0012]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an array diagram of a reticle according to one embodiment of the present invention. In this figure, those having the same reference numerals as those in FIG.

The extra-fine pattern 5 is a pattern for releasing electricity charged to other metal patterns, and is inserted into a portion which is easily discharged due to an edge effect such as a corner portion of the pattern or a narrow portion between the patterns, and is resolved. It has a thickness less than the limit. The thickness can be defined by the following equation (Rayleigh equation), and can be formed simultaneously with the formation of another metal pattern such as the circuit pattern 1.

[0015]

(Equation 1)

In the above equation, the process constant k1 is determined by, for example, resist baking.

With such a structure, the charged electric charge can be released through the inserted fine pattern 5 through a handling arm or the like on the apparatus side such as a stepper or a scrubber. Destruction can be prevented. In addition, the ultrafine pattern of the present invention is not only electrically connected between one large group of metal patterns as shown in the figure, but also in each metal pattern, for example, a circuit pattern such as one layer in a multilayer wiring. There is an isolated portion or divided into a plurality of portions even inside the circuit pattern. Needless to say, in such a case, the isolated and divided portions may be used to electrically connect. .

The metal pattern such as the circuit pattern 1 is a so-called real pattern which can form a resist pattern in which the shape of the circuit pattern is transferred onto a semiconductor device in a later photolithographic process. Is
Since it is less than the resolution limit, it is not transferred onto the wafer.

Further, since the ultrafine pattern is made of the same material as the metal pattern to be the actual pattern, it has the same resistance value per unit area, and is smaller than the resolution limit, so that it is thinner than the actual pattern. Therefore, the metal film has the highest resistance value among the metal films deposited on the glass substrate, and is under a condition that the metal film is easily broken by an electric current flowing through the metal film. However, since the resistance value is not so high as to cause dielectric breakdown (discharge) due to the edge effect in a part of another metal pattern, it plays a role like a fuse which is first destroyed by charging.

The environment in which the reticle is charged may affect not only the reticle manufacturing process but also other wafer processes, etc. Can be sensed quickly, and the occurrence of defects can be suppressed.

[0021]

As described above, the present invention has a structure in which a pattern less than the resolution limit is inserted and a charge is released without being charged, and loss of the reticle mask due to electrostatic breakdown can be prevented. it can.

Further, since the ultrafine pattern of the present invention is made of the same material as the other metal patterns, it has the highest resistance and is liable to be broken, and by observing the conditions, it is possible to quickly detect abnormalities in the process. Is possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing a semiconductor reticle mask of the present invention.

FIG. 2 is a diagram showing a conventional semiconductor reticle mask.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circuit pattern 2 Alignment pattern 3 TEG pattern 4 Light shielding pattern 5 Extra fine pattern

Claims (2)

[Claims] 1. A semiconductor reticle mask having a glass substrate and a metal pattern formed on the glass substrate, wherein the isolated patterns constituting the metal pattern are interconnected by an extremely fine pattern less than the resolution limit. It is characterized by being electrically connected. 2. The semiconductor reticle mask according to claim 1, wherein said ultrafine pattern is formed of the same material as said metal pattern.