RU2587096C2 - Processing of silicon substrate - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to fabrication of solid-state devices, particularly, to processing of silicon substrate backs before built-up processes. Claimed process consists in that the jet of particles of silicon carbide, their sizes not exceeding 6 mcm, is sprayed on silicon plate surface under the following process conditions: air pressure in the nozzle - 2.5±0.3 kg/cm², time - 5±0.1 minutes and table revolution speed - 20±4 rpm. Note here that the surface features good adhesive properties, plate depth scatter not exceeding 1.5±0.01 mcm, and rules out the origination of microfractures and mechanical strains that deteriorate the surface quality.

EFFECT: good adhesive properties, no mechanical strains or fractures, or chips.

4 ex

Description

The invention relates to a manufacturing technology of semiconductor devices, in particular to a method for processing the reverse side of silicon substrates before spraying processes.

There are various methods of processing and preparing the reverse side of silicon substrates with ready-made transistor structures to improve the adhesive properties of the surface before spraying processes during sputtering - mechanical and chemical.

Mechanical methods are based on the use of abrasive material during grinding and polishing [1]. The main disadvantage of these methods is that during processing microcracks form, which subsequently lead to the creation of a network of cracks and cause chips of individual sections, which degrades the characteristics of the device and reduces the percentage of suitable devices.

Chemical methods are based on the use of chemical solutions and etchants. Known methods for processing semiconductor materials in the etchant: nitric acid with hydrofluoric acid in alkali solutions KOH, NaOH at temperatures of 90-100 ° C and others [1].

The disadvantage of these methods is that chemical reagents introduce unwanted impurities onto the surface of the silicon substrate, which impair its electrophysical properties, and etchants can unevenly etch the surface, which affects the unevenness of the subsequent deposition.

The technical result of the invention is to obtain a silicon surface with good adhesion to sprayed metals, uniform in thickness with no mechanical stresses, cracks and chips.

The essence of the method lies in the fact that a stream of silicon carbide is directed to the surface of the silicon wafer at a distance under the following technological conditions: air pressure in the nozzle - 2.5 ± 0.3 kg / cm ² , time - 5 ± 0.1 minutes and speed tables 20 ± 4 rpm. Moreover, the surface has good adhesive properties, the spread in the thickness of the plate is not more than 1.5 ± 0.01 μm, and the occurrence of microcracks and mechanical stresses that impair the quality of the surface are excluded.

The invention is confirmed by the following examples.

EXAMPLE 1: The process is carried out on a sandblasting unit, where silicon wafers are mounted on the plate holders of a rotary table using vacuum tweezers. Then set the time for processing, turn on the rotary table (i.e. set the speed of rotation of the table) and subsequently turn on the injection of sand from the sandblasting nozzle, at the same time turn on the nozzle on time. Silicon carbide (SiC) powder with a sand particle size of not more than 6 microns is used as an abrasive material. Then they stop the rotation of the table and unload the plates. At the end of the process, the injection of sand from the nozzle is stopped. The sandblasting process is carried out under the following technological conditions: air pressure in the nozzle - 1.5 ± 0.3 kg / cm ² , time - 5 ± 0.1 minutes, nominal table rotation speed of 15 ± 2 rpm.

Control is carried out by the thickness of the plates. The spread across the plate thickness is 1.8 μm ± 5%.

EXAMPLE 2: The process is carried out similarly to the condition of example 1. The sandblasting process is carried out under the following conditions: air pressure in the nozzle - 2.0 ± 0.3 kg / cm ² , time - 10 ± 0.1 minutes, nominal table rotation speed 10 ± 4 rpm

The control is carried out by the thickness of the plate, the spread of which is 2.0 μm ± 5%.

EXAMPLE 3: The process is carried out similarly to the condition of example 1. The sandblasting process is carried out under the following conditions: air pressure in the nozzle - 2.0 ± 0.3 kg / cm ² , time - 7 ± 0.1 minutes and table rotation speed of 20 ± 4 rpm

The control is carried out by the thickness of the plates, the spread of which is 2.2 μm ± 5%.

EXAMPLE 4: The process is carried out similarly to the conditions of example 1. The sandblasting process is carried out under the following conditions: air pressure in the nozzle - 2.5 ± 0.3 kg / cm ² , time - 5 ± 0.1 minutes, nominal table rotation speed of 20 ± 4 rpm

The control is carried out by the thickness of the plates, the spread of which is 1.5 μm ± 5%.

Thus, the proposed method in comparison with the prototype allows to obtain plates with good adhesion, uniform in thickness, where the spread is 1.5 μm ± 5%, and without mechanical stress.

Literature

1. Kurnosov A.I., Yudin V.V. Technology for the production of semiconductor devices and integrated circuits, M .: "Higher school", 1986, p. 177-178.

Claims (1)

A method of surface treatment of silicon substrates, including the processing of silicon wafers in a sandblasting installation, characterized in that particles of silicon carbide no larger than 6 microns are used as sand under the following conditions: air pressure in the nozzle - 2.5 ± 0.3 kg / cm ² , the duration is 5 ± 0.1 minutes and the nominal rotation speed of the table is 20 ± 4 rpm, the variation in the thickness of the silicon wafers is not more than 1.5 ± 0.01 μm.