RU205508U1 - EXPLOSIVE PHOTOLITHOGRAPHY MASK - Google Patents

Abstract

The field of application of the proposed utility model is microelectronics, and can also be used in the manufacture of a number of electronic devices, for example, for the formation of a Schottky contact, metallization from materials that are weakly etched. The result of the proposed utility model is to expand the possibility of using a mask for applying working layers using magnetron sputtering. This result is achieved by the fact that, in contrast to the known mask for explosive photolithography, which consists of a resist layer for explosive lithography, a photoresist with a pattern on the processed plate, in the proposed mask for explosive photolithography between the resist layer for explosive lithography and photoresist an additional layer of aluminum with a thickness of 0 , 2≤d≤0.3μm.

Description

The field of application of the proposed utility model is microelectronics, and can also be used in the manufacture of a number of electronic devices, for example, for the formation of a Schottky contact, metallization from materials that are not easily etched.

Known mask for explosive photolithography, consisting of a layer of photoresist with a pattern on the processed plate (see, for example, the article "The method of explosive photolithography as a solution to the problems of complex semiconductor systems" L. Ryabtsev; scientific supervisor VM Komarovskaya // Engineering pedagogical education in the XXI century: materials of the Republican scientific-practical conference of young scientists and students, May 24-25, 2018 - Minsk: BITU, 2018. - Part 2. - P. 185-187.).

The thickness of the photoresist is chosen equal to 1.5-2 of the thickness of the metal layer.

The main disadvantage of this mask is that it is necessary to maintain the verticality of the photoresist walls and a large distance from the metal source to the processed plate, in order to be able to remove the photoresist through its side wall in relief to form a metal pattern.

The above disadvantages are partially eliminated in the mask, consisting of a layer of photoresist and resist for explosive lithography (LOR) with a pattern on the processed wafer (see, for example, the article by MicroChem "LORLift-Off Resists" https: //research.engineering.ucdavis. edu / cnm2 / wp-content / uploads / sites / 11/2013/05 / LOR_Data_Sheet.pdf).

When a pattern is formed in a resist layer for explosive lithography (LOR), the dimensions of the resulting holes are slightly larger than the dimensions of the pattern in the photoresist, which makes it possible to remove the photoresist through its side wall in relief to form a pattern from the metal, however, it is necessary to maintain a large distance from the metal source to the processed plate.

The main disadvantage of this mask is that with the widespread magnetron sputtering of sufficiently thick layers of metal films (0.3 μm and more), the border of the photoresist overhanging the layer (LOR) rises and the metal dusting of the side walls (LOR) occurs, which makes it difficult separation of metallization areas and impairs the reproducibility of the explosive photolithography process.

The result of the proposed utility model is the expansion of the possibility of using a mask for applying working layers using magnetron sputtering.

This result is achieved by the fact that, in contrast to the known mask for explosive photolithography, consisting of a resist layer for explosive lithography, a photoresist with a pattern on the processed plate, in the proposed mask for explosive photolithography, an additional layer of aluminum is introduced between the resist layer for explosive lithography and photoresist, thickness 0.2≤d≤0.3μm.

Thus, the aluminum layer in the mask is not deformed during metal deposition and the side wall of the resist for explosive lithography is not covered with the deposited metal, which simplifies its removal, even in the case of magnetron metal deposition.

The minimum size d is due to the fact that at a smaller thickness there will be no rigidity of the "canopy" of aluminum.

The maximum dimension d is due to the fact that with a greater thickness of aluminum, the dimensional accuracy deteriorates.

The essence of the proposed utility model is illustrated by Figures 1-5.

FIG. 1 semiconductor wafer with deposited resist (LOR), layer of aluminum mask, layer of photoresist.

FIG. 2 semiconductor wafer with a formed pattern in the photoresist.

FIG. 3 a semiconductor wafer with a formed pattern in a photoresist, in an aluminum mask layer and in a resist layer (LOR).

FIG. 4 semiconductor wafer after applying the working layer.

FIG. 5 semiconductor wafer with a metal layer, the pattern of which was obtained by explosive photolithography.

The positions in FIG. 1-5 are indicated:

1 - semiconductor plate;

2 - resist layer for explosive lithography;

3 - a layer of an aluminum mask;

4 - photoresist layer;

5- applied metal layer;

6 - area for etching;

7 - metal layer, the pattern of which was obtained by explosive photolithography.

The main stages of manufacturing and using the proposed mask are described below using the example of a semiconductor wafer.

On a semiconductor wafer 1, consisting of a silicon substrate, a layer of resist for explosive lithography 2 of the LOR 5A brand with a thickness of 0.6 μm is applied by centrifugation, followed by drying at 125 ° C, 180 ° C.

Then a layer of aluminum is applied to form an aluminum mask 3 by the method of electron-beam sputtering with a thickness of 0.2-0.3 microns. Then a layer of photoresist 4 grade S1813G2SP15 with a thickness of 1 μm is applied and photolithography is performed to form an area for etching 6 layers 2, 3.

Next, the layer of the aluminum mask 3 is removed by liquid etching (etchant for aluminum H3PO4: HNO3: H3COOH: H2O = 73%: 3, l%: 3.3%: 20.6%), plasma-chemical etching is possible to obtain smaller sizes.

Then a layer of resist for explosive lithography 2 in oxygen plasma is etched. Next, a layer of metal (titanium, gold) with a total thickness of 0.3 microns is applied by magnetron sputtering. Then carry out the removal (explosion) of layers 2,3,4 in nitric acid, which penetrates into the side walls of section 6 and removes layers 2,3,4.

Claims (1)

A mask for explosive photolithography, consisting of a resist layer for explosive photolithography, a photoresist with a pattern on the processed plate, characterized in that an additional layer of aluminum with a thickness of 0.2≤d≤0.3 μm is introduced between the resist layer for explosive lithography and the photoresist.

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