JP2001107230A - Substrate holder for sputtering film formation and method of manufacturing photomask blanks using the same - Google Patents

Abstract

(57) Abstract: Provided is a substrate holder for sputtering film formation, in which a sputter voltage does not fluctuate when a predetermined film is formed on a glass substrate by sputtering, and a method for manufacturing a photomask blank using the same. With the goal. A substrate holder includes a frame portion made of metal or the like and a portion on which a glass substrate is placed. A dummy portion of a predetermined size made of glass of the same material as the glass substrate is provided on the frame portion. It is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate holder and a method of manufacturing a photomask blank used in a sputtering film forming apparatus for manufacturing a photomask blank for a photomask used in manufacturing a semiconductor integrated circuit or the like. It is about.

[0002]

2. Description of the Related Art In the manufacture of semiconductors such as semiconductor elements, ICs, and LSIs, the process of manufacturing a photomask used for transferring a fine pattern onto a semiconductor wafer is usually performed by precision polishing of quartz glass or the like. Polishing process for obtaining a light-transmitting substrate, film-forming process for forming a light-shielding film such as chromium on one main surface of a light-transmitting substrate by sputtering, etc., resist coating process for applying a resist film on the light-shielding film by spin coating or the like An exposure step of selectively exposing the resist film through a master mask having a predetermined pattern, an etching step of developing the exposed resist film with a predetermined developer and performing etching to obtain a predetermined light-shielding film pattern Done. Here, the glass substrate on which the light-shielding film and the like are formed in the film forming step is generally called a photomask blank.

[0003] A conventional process for producing this photomask blank using a continuous sputtering apparatus will be described. FIG. 2 is a sectional view showing a conventional continuous sputtering apparatus. Reference numeral 22 denotes a film forming chamber in which a film forming process by sputtering is performed. Reference numeral 23 denotes a load isolation chamber, on which a glass substrate on which a film forming process is to be performed is mounted on a substrate holder 40, and is supplied into the film forming chamber 22 from here. The substrate holder 40a on which the glass substrate is placed is subjected to a film forming process in the film forming chamber 22, discharged to the unloading isolation chamber 24, and stocked. In the film forming chamber 22, there are a lower electrode 26 and an upper electrode 27 for performing plasma excitation, and a target 25 is fixed on the lower electrode 26. The target 25 is made of a metal which is a main component of a compound to be formed into a film. 29 is a chimney and target 25
Is a component for controlling the direction in which atoms struck out of the glass substrate fly to the glass substrate so as not to scatter in the film formation chamber.
It also serves as a barrier to prevent diffusion into the interior. However, the chimney 29 is not an essential component and may be omitted. Reference numeral 28 denotes a gas introduction port through which a gas for exciting plasma is introduced into the film formation chamber. Reference numeral 31 denotes a vacuum exhaust system, which maintains a degree of vacuum and controls a gas flow rate. The substrate holder 40a on which the glass substrate supplied into the film forming chamber 22 is placed has the same potential as the upper electrode 27, and may have the same function as the upper electrode 27.

A substrate holder 40 on which a glass substrate is placed
a is supplied from the load isolation chamber 23 into the film forming chamber 22 and moves in the film forming chamber 22 in the horizontal direction. While the substrate holder 40a moves between the target 25 fixed on the lower electrode 26 and the upper electrode 27, the target 2
The atoms struck out from 5 adhere to the lower surface of the glass substrate and are formed into a film having a predetermined thickness. The holder 41b on which the glass substrate on which the film forming process has been performed is further moved in the horizontal direction, and is moved from the film forming chamber 22 to the unload isolation chamber 24.
Is discharged and stocked.

[0005] The sputtering voltage fluctuates while the holder 40a on which the glass substrate is placed is moving in the film forming chamber 22, and the film quality of the compound deposited on each glass substrate in the holder varies. As a result, there arises a problem that optical characteristics such as light transmittance and reflectance vary. Here, the sputtering voltage refers to a potential difference between the upper electrode 27 and the lower electrode 26.

The cause of the fluctuation of the sputtering voltage will be described below. Between the upper electrode 27 and the lower electrode 26, when the glass substrate of the substrate holder 40a on which the glass substrate is mounted passes, and when the substrate holder 4 on which the glass substrate is mounted
It was found that there was a difference in the sputter voltage when the portion 41 of the frame 0a passed. That is, the substrate holder 40a is provided between the upper electrode 27 and the lower electrode 26.
When the glass substrate passes through, the sputtering voltage is higher than when the frame portion 41 of the substrate holder 40 passes. This is because the dielectric constant of glass is
This is because the dielectric constant of the metal (such as aluminum) constituting the frame portion 41 of the substrate holder 40 is higher than that of the metal. As a result, there is a difference between the film quality deposited on the glass substrate when the sputtering voltage is high and the film quality deposited on the glass substrate when the sputtering voltage is low.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a substrate for sputtering film formation in which a sputtering voltage does not fluctuate when a predetermined film is formed on a glass substrate by sputtering. An object of the present invention is to provide a holder and a method for manufacturing a photomask blank using the holder.

[0008]

In order to solve the above-mentioned problems in the present invention, first, in claim 1, a substrate holder on which a plurality of glass substrates are mounted includes a load isolation chamber, a film forming chamber, and an unloading chamber. In a continuous sputtering film forming apparatus in which a predetermined film is formed on a glass substrate by moving a load isolation chamber, the substrate holder is provided with glass on at least a part of a frame portion excluding a portion on which the glass substrate is mounted. And a substrate holder for sputtering film formation, wherein a dummy portion is formed.

According to a second aspect of the present invention, there is provided a photomask wherein a light-shielding film such as chromium is formed on a glass substrate by a sputtering film forming apparatus using the substrate holder for a sputtering according to the first aspect. This is a blanks manufacturing method.

[0010]

Embodiments of the present invention will be described below. FIG. 1 is a plan view showing an embodiment of a substrate holder for sputtering film formation according to the present invention. Substrate holder 1
Reference numeral 0 denotes a frame portion 11 made of metal or the like and a portion 12 on which a glass substrate is placed. The frame portion 11 is provided with a dummy portion 13 of a predetermined size made of glass of the same material as the glass substrate. The ratio of the area occupied by the dummy portion 13 to the frame portion 11 can be appropriately set as long as the function as the substrate holder can be maintained. By adopting such a structure of the substrate holder, it is possible to eliminate the fluctuation of the sputtering voltage during the sputtering film formation, thereby preventing the variation of the film quality deposited on the glass substrate, and setting the substrate holder. In addition, variations in optical characteristics such as light transmittance and reflectance in the plane of each photomask blank can be eliminated.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A substrate holder 10 of the present invention comprises a frame portion 11 made of aluminum or the like and a portion 12 on which a glass substrate is placed. A dummy portion 13 was formed by fitting a glass substrate. Further, a glass substrate was set using the substrate holder 10 and loaded into a load isolation chamber of a sputtering film forming apparatus, and chromium was sputtered to a predetermined thickness in the film forming chamber to produce a photomask blank. . Thus, since the dummy portion 13 is made of glass in the frame portion 11 of the substrate holder 10, the dielectric constant of the entire holder can be made closer to the dielectric constant of glass. As a result, there is no difference in sputtering voltage between when the glass substrate passes between the lower electrode and the upper electrode of the sputtering film forming apparatus and when the frame portion of the holder passes. Thus, a photomask blank having no variation in optical characteristics such as light transmittance and reflectance could be obtained.

Comparative Example Using a conventional substrate holder 40 shown in FIG. 3, a film was formed by sputtering using the same apparatus as in the embodiment, and a photomask blank was produced. Since the frame portion 41 of the substrate holder 40 is entirely made of a metal such as aluminum, the dielectric constant of the frame portion is significantly lower than that of the glass substrate. As a result, the gap between the lower electrode and the upper electrode is There is a large difference in the sputter voltage between the time when the light passes and the time when the frame portion 41 passes, and the optical characteristics such as the transmittance and the reflectance of the in-plane light of the obtained photomask blank are obtained. Showed variation.

[0013]

As described above, by performing the sputtering film formation using the substrate holder of the present invention, the fluctuation of the sputtering voltage during the sputtering film formation can be eliminated, and as a result, the quality of the film deposited on the glass substrate can be reduced. Variations can be prevented, and variations in optical characteristics such as light transmittance and reflectance in the plane of each photomask blank set in the substrate holder can be eliminated.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a substrate holder according to the present invention.

FIG. 2 is a schematic sectional view illustrating an example of a sputtering film forming apparatus.

FIG. 3 is a plan view showing an example of a conventional substrate holder.

[Explanation of symbols]

10, 40 ... substrate holder 11, 41 ... frame part 12, 42 ... part on which glass substrate is mounted 13 ... dummy part 22 ····· Deposition chamber 23 ···· Load isolation chamber 24 ····· Unload isolation chamber 25 ····· Target 26 ······ Lower electrode 27 ··· ... Upper electrode 28... Gas inlet 29... Chimney 31... Vacuum exhaust system 40 a. 40b ...... Substrate holder on which the deposited glass substrate is placed

Claims (2)

[Claims] 1. A continuous sputtering film forming method in which a substrate holder on which a plurality of glass substrates are mounted moves in a load isolation chamber, a film formation chamber and an unload isolation chamber to form a predetermined film on a glass substrate. In the apparatus, the substrate holder has a dummy portion formed of glass on at least a part of a frame portion excluding a portion on which the glass substrate is mounted, and a substrate holder for sputtering film formation. 2. A method for manufacturing a photomask blank, comprising forming a light-shielding film such as chromium on a glass substrate using a sputtering film-forming apparatus using the substrate holder for sputtering according to claim 1.