JPS63276052A - Manufacture of photomask - Google Patents

Abstract

PURPOSE:To obtain a fine mask pattern with high accuracy, by taking directly electric conduction from a layer whose electric resistance is small, of the end face of a hard mask substrate in a process for forming a resist pattern by an electron beam exposing device. CONSTITUTION:As for a hard mask substrate 1, a metallic thin film 3 whose electric resistance value is small, such as Cr, etc. is formed on a transparent substrate 2 of glass, etc., a surface layer 4 of a metal oxide film is formed thereon, so as to have a function for preventing surface reflection, and also, on the surface layer 4, a resist layer 5 is formed. Also, on the substrate end face of the hard mask substrate 1, an exposing part 7 is formed on the metallic thin film 3 whose electric resistance is small, of the lower layer, therefore, at the time of an electronic exposure, a radiated electron transmits through the resist layer 5, reaches the layer whose electric resistance is large, of the surface layer 4, and thereafter, instantaneously, it is structured so as to be movable easily to an electric conduction pin 6 from the metallic thin film 3 of the lower layer whose electric resistance is smaller. In such a way, a photomask of fine pattern can be obtained with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the production of photomasks used in semiconductor production and the like.

[Conventional technology]

In the process of forming a pattern on the resist of a hard mask substrate-H in the production of photomasks used in semiconductor production, etc., a light exposure device or an electron beam exposure device may be used.

FIG. 3 shows a step of forming a resist pattern on a hard mask substrate using an electron beam exposure apparatus. That is, the hard mask substrate l used for making a photomask is a light-shielding film formed by forming a single layer or multiple layers of a metal thin film such as Cr on a transparent substrate 2 such as Canilas.

Among these, especially the f layer is a thin metal with low electrical resistance. On the other hand, a layer such as a transparent metal oxide film is formed on the surface layer 4 to have a surface antireflection function.
Furthermore, a resist rrj5 is formed on the surface M4.

Then, the resist layer 5 is exposed to an electron beam.
The electrons that have reached the resist layer 5 pass through the resist layer 5 while exposing the resist, and reach the surface layer 4 of the hard mask substrate 1 . If these electrons are charged directly on the hard mask substrate, they will cause a potential drop and will also block the arrival of subsequent incident electrons, leading to a decrease in the amount of exposure to the resist film and destabilization, causing damage to the resist film. This causes uneven exposure in the pattern, making it difficult to form highly accurate fine patterns. Therefore, even in the photomask finally obtained by developing such a resist film and etching the hard mask substrate 1, it is difficult to form a fine pattern with high precision. In order to prevent this problem, conventional electron beam exposure apparatuses adhere conductive pins 6 to the surface of the hard mask substrate 1 to establish electrical continuity and prevent the hard mask substrate 1 from being charged.

[Problem that the invention seeks to solve]

However, in the process of forming a resist pattern on a hard mask substrate using the above conventional electron beam exposure apparatus, since the electrical resistance of the surface layer 4 is large, during exposure using the electron beam exposure apparatus, The arrived electrons cannot move through the surface layer 4 and cannot reach the conductive pins 6, and even if they move from the surface layer 4 to the lower metal thin film layer 3 where they can freely move, the surface The problem is that the layer 4 acts as a barrier and cannot reach the conductive pin 6. As a result, conventional conduction methods cannot prevent a hard mask substrate having such a configuration from being charged during electron beam exposure.

Conventionally, as a means to solve this problem, an improved blocking plate has been devised in which the surface layer 4 has a lower resistance to energy, but this has not achieved the function of preventing surface reflection, which is the original purpose of the dry plate.

In reality, the reflectance of a low-reflection substrate is usually 10 at 436 nm.
%, whereas the improved substrate has a reflectance of 436n.
The reflectance increases to around 30% at m. Therefore, such methods have not essentially solved the problems of the prior art.

Furthermore, the conventional method has the problem of damaging the resist layer 5 because the conductive pins 6 are bonded to the surface of the hard mask substrate 1.

The present invention solves the above-mentioned problem, and provides a photomask with a highly accurate fine pattern by exposing the hard mask substrate to light without being charged in the electron beam exposure process even if the surface layer of the hard mask substrate has a large electrical resistance. The purpose of the present invention is to provide a photomask manufacturing method that enables the following.

[Means for solving problems]

To this end, the photomask manufacturing method of the present invention uses a hard mask substrate to form a resist pattern using an electron beam exposure device in a method of manufacturing a photomask used for manufacturing a semi-demolition body, etc. using a hard mask substrate. It is characterized by direct conduction from a layer with low electrical resistance on the end face.

[Effect]

In the present invention, for example, as shown in FIG. 1, on the substrate end surface of the hard mask substrate l, an exposed portion 7 is formed in the underlying metal thin film 3 with low electrical resistance, so that during electronic exposure, as shown in FIG. As shown in FIG.
After reaching the surface layer 4, which has a high electrical resistance, it can instantly move easily from the lower metal thin film 3, which has a lower electrical resistance, to the conductive pin 6.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1st
The figure is a perspective view of a hard mask substrate for explaining one embodiment of the photomask manufacturing method of the present invention, and FIG. 2 is a diagram for explaining the operation of FIG. 1. In the figure, 1 is a hard mask substrate, 2 is a transparent substrate, 3 is a metal thin film, 4 is a surface layer, and 5
6 indicates a resist layer, 6 indicates a 6-electrode pin, and 7 indicates an exposed portion.

In FIG. 1, the hard mask substrate 1 is formed by forming a metal thin film 3 having a small electric resistance value such as C on a transparent substrate 2 such as glass, and coating a surface N4 such as a transparent metal oxide film on top of it. The surface layer 4 is formed to have a surface antireflection function.
A resist Hi5 is formed on top of the resist. On the substrate end surface of the hard mask substrate 1, an exposed portion 7 is formed in the underlying metal thin film 3 with low electrical resistance, so during electron exposure, the irradiated electrons are transferred to the resist as shown in FIG. After passing through the layer 5 and reaching the surface layer 4, which has a high electrical resistance,
It has a structure that allows it to be easily moved from the lower metal thin film 3, which has lower electrical resistance, to the conductive pin 6 in an instant.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made.

For example, in the second embodiment, the hard mask substrate 1
Although the exposed portion 7 of the underlying metal thin film 3 having low electrical resistance is formed on the end surface of the substrate, the exposed portion 7 of the metal thin film 3 may be formed on the substrate surface near the end surface.

〔Effect of the invention〕

As explained above, in the present invention, a hard mask having a layer with high electrical resistance on its surface layer (even if it is a plate, has conductivity directly or equivalent to the underlying metal thin film with low electrical resistance). Therefore, during electron beam exposure, the irradiated electrons can make contact with the resist layer.
3, and after reaching the surface layer with high electrical resistance, the electric wind (which can easily reach the conductive pin through the original small underlying metal thin film, reduce the charging of the hard mask law plate) Therefore, it is possible to obtain a fine mask pattern with high precision.

Furthermore, since the conductive pin is bonded to the end surface of the hard mask substrate, conduction can be achieved without damaging the resist layer.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a hard mask substrate for explaining one embodiment of the photomask manufacturing method of the present invention, and FIG.
FIG. 3 is a perspective view of a conventional hard mask substrate. 1... Hard mask substrate, 2... Transparent substrate, 3...
・Metal thin film, 4... Surface layer, 5... Resist layer, 6
...Conductive bottle, 7...Exposed part. Applicant Dai Nippon Printing Co., Ltd. Representative Patent Attorney Hiroki Shirai (2 others) Figure 1 Figure 2

Claims (2)

[Claims] (1) In a method of manufacturing photomasks used in semiconductor manufacturing etc. using a hard mask substrate, direct conduction is established from a layer of low electrical resistance on the end surface of the hard mask substrate during the process of forming a resist pattern using an electron beam exposure device. A photomask manufacturing method characterized by taking the following steps. (2) The photomask manufacturing method according to claim 1, wherein the hard mask substrate has a layer having low electrical resistance formed on an end surface of the substrate.