JPS58195846A - Blank for chromium mask - Google Patents

Abstract

PURPOSE:To obtain a blank giving a hard photomask for manufacturing a semiconductor integrated circuit at a high etching speed with superior productivity, by forming a chromium layer contg. carbon and a chromium oxide layer on a substrate. CONSTITUTION:Chromium is deposited on a substrate by vapor deposition or sputtering in an atmosphere contg. a compound having carbon in the molecule such as methane or acetylene to form a chromium layer contg. about 0.001- 30wt% carbon, and a chromium oxide layer is formed on the chromium layer to obtain a blank for a photomask. Carbon may be also contained in the chromium oxide layer A. photoresist layer is formed on the blank, imagewise exposed, and developed to imagewise disclose the suface of the blank. The chromium oxide layer and the chromium layer are then dry-etched to manufacture a hard mask for manufacturing a semiconductor integrated circuit, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photomask material used in the manufacturing process of semiconductor integrated circuits and high-density integrated circuits.

2. Description of the Related Art Hard masks used as photomasks in the manufacturing process of semiconductor integrated circuits and the like are widely used because they have higher resolution and durability than conventional emulsion masks. A typical hard mask is a chrome mask, and in particular, a so-called anti-reflection type chrome mask, in which a chromium oxide layer is laminated on the surface of a chromium layer and acts as an ImK anti-reflection layer, is widely used.

L-line patterns have become finer, and with conventional wet chemical etching, the image quality of etched patterns deteriorates, making it difficult to form fine patterns.F-line processing was proposed as an etching method that eliminates this drawback. . However, when performing dry etching, the etching rate of a laminated film of a chromium layer and a chromium oxide layer is low, leading to a decrease in hardmask productivity. The purpose is to provide a hard master material with high productivity for hard masks.The purpose is to provide a chromium mask material having a chromium layer and a chromium oxide layer laminated on a substrate. This is achieved using a chrome mask material characterized by containing carbon in the chromium layer. A more preferred embodiment is achieved by including carbon in both the chromium layer and the chromium oxide layer.

The present inventors investigated the speed improvement of dry etching of the above-mentioned chrome mask material 1. As a result, it has been found that the dry etching rate can be significantly improved by incorporating chromium oxide FIFK carbon into the chromium layer laminated on the substrate.

Based on the above findings, the amount of carbon contained in the aluminum layer and chromium oxide layer according to the present invention is 0001 to 30%,
Preferably it is 001-lowt%.

In addition, as a means of incorporating carbon into the chromium layer/chromium oxide layer, chromium is added in a conventional manner in an atmosphere containing a gas containing carbon atoms in its composition, such as methane gas (CH4), acetylene gas (C, H, etc.). Vacuum deposition or G1 based on
It can be sputtered and deposited on a substrate.

Alternatively, a chromium target containing chromium carbide, or a chromium target with pores filled with carbon, is sputtered in an inert gas atmosphere to deposit a chromium layer on the support to form saponified chromium. The layer can be formed by sputtering a four-layer target in an atmosphere containing oxygen as described above.

The chrome mask material of the present invention obtained in this way is
It can be processed in accordance with a commonly used method for making a chrome mask from a chrome mask material, and is particularly suitable for a method for making a chrome mask using "K)" litching.

For example, a photoresist (preferably 7 photoresist for dry etching) suitable for the engraving to be used is applied to the chrome mask material of the present invention and prebaked, and an image is printed with active radiation for the photoresist) and developed. The surface of the chrome mask material was washed with water and subjected to RF etching in a mixture of CCI and air ((3°C) and 1°C) in a plasma etching system.
Plasma etching (dry etching) is performed by applying a power of about 300 W, and then the photoresist is ashed using oxygen plasma or the like to create a chrome mask.

In the above-mentioned dry etching, the first measurement example compares the dry etching speed of the carbon-containing chromium layer and the chromium oxide layer according to the present invention with the dry etching speed of the two types of layers in general. It is shown in Fig. 2 and Fig. 2. It is clearly shown that the dry etching rate can be increased several times by incorporating carbon into the layer.

Next, a more specific explanation will be given using examples.

Example 1 (11) A glass substrate was installed in a sputtering device.
After evacuation to Xl0 Torr, a mixed gas of Ar gas and CH4 gas is introduced until the pressure becomes 5 mTorr 4C.
is 1%.

(2) A voltage of 3007500 V is applied to one node and the cathode of the sputtering device to generate plasma, and chromium is used as a target. Form a layer □ (3) Then C) A whose content of 14 gas is 3-30%
Introduce a mixed gas of r and 0 until the pressure reaches 5 mTorr.
0 vI) IIE pressure is applied to generate plasma, and chromium is targeted, and a thickness of 30 mm is deposited on the chromium film.
A saponified chromium layer containing carbon is formed in step 01.

伜) As above, the chromium layer and chromium oxide layer are fl
Photoresist Z 1350 (
Silapray Co., Ltd.) was applied to a thickness of 500X and heated (prebaked) in air for about 30 minutes at a temperature of 90" to solidify the resist layer.

(6) Expose and develop the first layer of Gekiki PhotoRegikai,
A desired resist pattern is formed.

(7) Using the first generation registration pattern as a mask, a pattern is formed by etching the portions of the chromium layer and chromium oxide layer that are not covered by this mask using the following dry process.

Using a cylindrical plasma etching device, CCj4 gas and 0. Gas mixture (gas group y, CC14=to=l
:2) When the chromium layer and chromium oxide were etched using K, it took only 2 minutes.

In addition, 1 gas pressure is 0.3Thrh high frequency output is 150W,
The aperture ratio of the pattern is 30%.

Figure 1 shows the etching rates of the chromium layer and chromium oxide layer in this example using the conventional method using only chromium gas and Ar gas.
A comparison is shown with the etching rates of a chromium layer and a chromium oxide layer created with +O gas.

Example 2 (1) A chromium layer and a chromium oxide layer are formed by reactive sputtering under the same conditions as in Example 1.

(2) A resist is applied in the same manner as in Example 1, prebaked, exposed and developed to form a desired pattern.

(3) Using a balanced flat plate mold and 7-cut ion etching apparatus, CCl4 gas and 0.0. Etching of the chromium layer and chromium oxide layer using a gas mixture (gas composition C (J, :0.=3:4) was completed in 1 minute I seconds.
0. ZTorrx high frequency power (GO 200W, pattern aperture ratio is 30%).

Figure 112 shows the chromium layer and oxidation in this example.
The etching rate of No. 41 is shown in comparison with the etching rates of a chromium layer and an oxide layer prepared using conventional methods.

The results described above for Actual #Ii$11 and 2 are compared with those of the conventional type and are shown in Table IK.

Table 1 As detailed above, according to the present invention, it is possible to increase the etching speed by dry processing of a chromium mask material containing carbon in the chromium layer or chromium oxide layer, thereby improving throughput.

[Brief explanation of drawings]

FIG. 1 shows the etching rate of the chromium layer and chromium oxide layer by the cylindrical plasma etching device 11c, and FIG. 2 shows the etching rate of the chromium layer and the chromium oxide layer by the parallel plate type reactive ion etching device. It shows d degrees. Agent Yoshi Kuwahara Beautiful procedural amendment 11i1'11ノ, j, 1973 19th effect'1h/Ha Noko tsees
-ji-', 5Ctill... (□!'j
・Tarom Mask Material - Sleeves 11 I?゛1i fj2 I open sound holding, '1 piece 1 person 11゛ji
East IIl Capital i1i Ii Ward West 41 Inn + 1'1126 Duke 2ya)j: f'i' 11271 Konishi 6lj° Tei 1-Gyo Co., Ltd'f1 generation no, j [Small? Nobuhiko Moto for τλ! 1.: , 11 Medium.: "A: II J'f
1ji 7. <r) Town 1, 'l ''e! 6, Subject of amendment l!

Claims (1)

[Claims] (1) A chromium mask material having a chromium layer and a chromium oxide layer laminated on a substrate, characterized in that carbon is contained in the chromium layer formed on the substrate. ■) Claims characterized in that a chromium oxide layer containing carbon is provided on the chromium layer containing carbon formed on the substrate! ! Chrome mask material described in section g1