SU864383A1 - Pattern for roentgenolythography - Google Patents

Description

The invention relates to semiconductor manufacturing and can be used in microelectronics for obtaining by means of X-ray lithography semiconductor structures with submicron dimensions. A known template for X-ray lithography, consisting of a thin transparent Mylar film, which serves as a membrane tensioned on a supporting ring. A chromium underlayer is deposited on the surface of the film, which improves the adhesion of the membrane to the X-ray absorber layer, which uses gold 11. However, templates of polymeric materials are characterized by an insufficiently equal surface, low thermal conductivity, which makes it difficult to remove heat generated by absorbed X-rays, film deformations near fixed edges, leading to distortion of the pattern, transparency of the Mylar membrane, significantly decreasing due to the presence of an additional chromium layer . The closest to the proposed technical essence is the X-ray lithographic chalice containing a silicon substrate with through-holes, on the surface of which lightly doped n - and lightly doped n + layers are created. A layer of aluminum oxide is placed over these layers, forming a membrane (transparent for X-rays) in the through holes of the substrate, on which a layer of gold from the chromium substrates is deposited, formed in accordance with the topology pattern and serves as an X-ray absorber. Silicon patterns have high strength and dimensional stability; they have full compliance with thermal expansion with thermal expansion of silicon substrate 2. The disadvantages of these templates are poor adhesion of gold to the membrane, brittleness, low optical transparency in whitespace, eliminating optical lighting, low-tech because of the complexity of manufacturing a membrane , the presence of additional operations, in particular, the operations of applying chromium underlayer.

The purpose of the invention is an increase in the meanic strength of the template and the manufacturing technology.

The goal is achieved by the fact that the X-ray lithography pattern, which adheres to the substrate with SCORES, an X-ray-transparent layer of aluminum oxide, which forms an edge in the through windows of the substrate, and an X-ray absorber layer deposited on the membrane surface in accordance with the topology pattern, is provided with an aluminum layer located on the surface of the substrate under a layer of aluminum oxide and in the body of the membrane under a layer of an x-ray absorber.

Figure 1 shows the substrate with an increased layer of aluminum and a layer of gold absorber in figure 2 - template blank with through windows in the substrate and a topology pattern in the gold layer; on fig.Z - a template, a section.

Template for x-ray lithography is made as follows.

On a substrate 1, for example, silicon by vacuum deposition, a layer of aluminum 2 tolgdine from 1 to 5 µm is deposited, which ensures the transparency of the X-ray membrane with A 8.3 X. The aluminum layer provides a good heat sink when exposing rents. gene rays and plays the role of a buffer in the event of a strain. Then a gold 3 layer with a thickness of 0.4 µm is deposited onto the aluminum layer by vacuum deposition, which provides good contrast of the illuminated pattern. After that, a topology pattern 4 is formed on the gold layer using electron beam lithography with a minimum size of 0.1 μm. In the body of the silicon substrate, the through windows 5 are opened by etching in the etchant:

Ethylenediamine68 ml

Water3 2 ml

Pyrocatechin 12 g

at 115 ° C, after which two-sided anodizing of aluminum is carried out under the conditions of obtaining wear resistant coatings.

Concentration 100 g / l Current density 2 A / dm Voltage 16 V

Temperature

electrolyte 15–20 ° C. Process time 30 min. After obtaining a continuous layer of aluminum oxide 6 in the gap areas of the figure, the anodization is completed. The aluminum oxide film 6 obtained by anodic oxidation differs from films of similar oxides obtained by other methods, higher strength, absence of internal stresses, high adhesion to the aluminum layer. In addition, the aluminum oxide film was obtained after the formation of an absorber layer in accordance with the topology of the pattern and is integral only in the whitespace. Under the X-ray absorber layer, the aluminum layer is retained, as well as on the surface of the silicon substrate a layer equal to half the thickness of the deposited aluminum layer. Due to aluminum islands in the dielectric membrane body of aluminum oxide, the template's structure acquires a number of positive qualities: due to plasticity, aluminum serves as a buffer to reduce deformations when internal stresses occur, aluminum has a high thermal conductivity and serves to remove heat generated in the absorber during exposure due to absorption x-ray, aluminum is more efficient than chromium gold-membrane material due to the fact that aluminum is very cheap, and steaming alumina in vacuo readily accomplished using evaporator as tungsten spiral filament. In addition, aluminum has good adhesion to oxides (in particular, to aluminum oxide) and gold with the formation of intermetallic compounds, reacts with a SiOo monolayer

which always in vivo covers the silicon wafers to form a reliable contact to the wafer.

This design of a high quality X-ray lithography pattern is easier to manufacture, i.e. more technological, has high mechanical strength and thermal conductivity. The template can be removed on standard equipment of semi-water technology with minimal expenditure of energy, time and money to obtain a solid membrane with high adhesion of the latter to the absorber.

For example, the cost of electricity for the production of AE-jOj with a thickness of 5 μm on a plate with a size of 1 dm is equal for anodic oxidation of alcmini:

P 2L.1BV-0.5h 0.016 kW, h. The power of the alumina recovery unit from the gas phase is about 20 kW, the deposition rate is 200500 A / min. It takes 100 minutes to obtain 5 μm alumina. Electricity consumption is:

RZ 20 kW-1.5 kWh

Thus, the power consumption in the second case is many times higher.

Claims (2)

1. The patent of the Fan no. 2261622, cl. H 01 L 21/308,1975. 2.Boy id State ResNpov, 1972, voe 15, No. 7, Spear D- Smith H.J. (prototype). -3 -2  Sh  1 R fig