JPS59201426A - Processing of semiconductor substrate - Google Patents

Abstract

PURPOSE:To easily remove damage and contamination generated due to the etching by covering semiconductor substrate where a diffused layer is formed with an insulating film, a window is opened by the dry etching, and annealing the exposed portion of diffused layer through irradiation of the light from the tangsten halogen lamp for a short period of time. CONSTITUTION:The N<+> type or P<+> type diffused layer is formed at the surface layer of P or N type Si substrate and an SiO2 film 3 is then deposited at the entire surface including it. The reactive ion etching is carried out corresponding to the diffused layer 2 to form a contact window 4 and thereby the annealing is carried out for a short period to the diffused layer 2 exposed in the window 4 under the specified ambient. At this time, the light of tungsten halogen lamp in the wavelength of 0.4-4.0mum is used for annealing for the period as short as several seconds to 10 and several seconds. Contamination and damage by irradiation generated during the annealing can be removed within a short period under the continuous annealing.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for treating semiconductor substrates, and in particular to a method for recovering and removing damage and contamination from dry etching repellent substrates.

BACKGROUND ART AND PROBLEMS Dry etching is one of the etching processes used in manufacturing semiconductor devices such as LSIs (Large Scale Integrated Circuits). Generally, in this dry etching, #! is etched by the etching gas components and the constituent materials of the etching container. - If the surface of a conductor substrate is stained, or if reactive ion milling (RIM) or reactive ion etching (I'tIE) is used, the acceleration energy of the incident ions and electrons is large, so the semiconductor substrate may be damaged. It is well known that radiation damage such as crystal defects occurs. Therefore, conventional methods are used to solve these problems. That is, for example, (1) dry etching is performed by selecting conditions that cause less contamination and damage; (2) dry etching is stopped midway through etching, and then wet etching is performed with less contamination and damage. (3) After dry etching has been completed, the electrically active area can be removed by other means that cause less contamination and damage. This is a method of removing contamination and damage caused to the area. Among these methods, (1) and (2)
) can be carried out relatively easily, but it lacks applicability in the manufacture of semiconductor devices such as LSIs, which require highly accurate micro-processing conditions as processing dimensions become smaller and higher density. However, the disadvantage is that the actual scope of use is very narrow. On the other hand, the method of (31) is a very versatile method compared to the methods of (Ll and (21).

Purpose of the Invention In view of the above-mentioned points, the present invention uses #r order short-time annealing as one of the methods described in (3) above to eliminate contamination and radiation +1 falseness generated on a semiconductor substrate during dry etching. The present invention provides a method for processing a semiconductor substrate that enables recovery.

SUMMARY OF THE INVENTION The present invention is a method for processing a semiconductor substrate, which includes the steps of dry etching the whole surface of the semiconductor substrate and irradiating the main opening with a lamp.

By using such a treatment method, contamination and radiation damage caused to the semiconductor substrate by dry etching can be removed in a short time.

Example originally hl! One example is as shown in Figure 1 A and B.
A diffusion layer (2) of Hj cedar is formed, and a contact window hole (4) facing the diffusion layer (2) is formed on the diffusion layer (2) by reactive ion etching (RIE). In the third aspect of the present invention, after forming the contact window hole (4) by reactive ion etching, a lamp beam with a wavelength of 0.4 to 4.0 μm is emitted from a tungsten halogen lamp. The surface of the diffusion layer (2) facing the contact window hole (4) is irradiated and annealed for a short time.Here, the diffusion layer (2) is made of As.
In the case of a diffusion layer, the above annealing can be performed in an oxygen atmosphere, and in the case of a diffusion layer of an impurity other than As, the above annealing can be performed in a vacuum.

According to such a processing method, the annealing time is short, ranging from several seconds to several seconds, so dry processing can be performed without affecting the impurity distribution (surface concentration, junction depth, etc.) of the already formed diffusion layer (2). Damage caused by etching can be removed.

In addition, in annealing using a normal furnace, the 5I02 film (
3) Secondary contamination from the furnace tube may occur on the surface of the diffusion layer (2) exposed by opening the window, but according to this invention, the contamination is prevented because the annealing tube is kept at a low temperature. Very few (
Become. Hydrogen is usually used as the annealing atmosphere, but
When oxygen is used, crystal defects in the 81 substrate can be annealed without causing redistribution of impurities;
Moreover, the thin 5i formed on the substrate surface by short-time annealing
The 02 membrane can be used to remove contamination from the extreme surface and prevent impurities from diffusing to the outside.

Further, when the annealing atmosphere is set to a solid wall, contamination on the extreme surface is vaporized and removed, and at the same time, the inside of the substrate is also annealed. However, when annealing is performed in the entire material, sufficient care must be taken to avoid etching of the substrate itself due to the high temperature, external diffusion of impurities, and omissions due to vaporization.

Figure 2 shows the results of measuring the degree of recovery of crystal defects in a silicon substrate using the Rutherford-Pack e-scattering (RBS) method using helium when using the treatment method of the present invention. A P-type silicon substrate with a specific resistance of 8 to 12 Ω was used.This silicon substrate was subjected to reactive ion etching (CF4 + H2r5Pa, 300 Ω).
The surface of the substrate was etched for 10 minutes with W) to cause contamination and radiation damage, and then cleaned with oxygen plasma for 30 minutes using a barrel-type etching device, and then etched with H
After boiling in a mixed solution of 2SO4 and HNO3, buffer H
Light etching was performed with F solution. This silicon substrate is exposed to a heater electric fi97 in an oxygen atmosphere (this is because the substrate is diffused with As, otherwise it is true).
Annealing was performed using a tungsten 710 gen lamp under conditions A while changing the irradiation time. Song fit (A)
, (B).

(C) and CD) are the measurement results when the irradiation time was 3 seconds, 4 seconds, 5 seconds, and 6 seconds, respectively. Also, the curve (E
) is the measurement result when using a (111) plane silicon substrate without dry etching or the above annealing,
Curve (F) is obtained after performing reactive ion etching under the same conditions as above using a P-type silicon substrate with a (111) plane.
These are the measurement results when the above-mentioned annealing was not performed. Second
In the figure, the smaller the value of the horizontal axis, the deeper the base,
The vertical axis indicates that the larger the value of 1 po, the more crystal defects there are. However, due to the difference in crystal plane between the (111) plane and the four planes) LB'
It was confirmed that there was almost no difference in the analysis of S. From this measurement result, it can be seen that when the main annealing was performed on the silicon substrate for 6 seconds (curve (D)), the crystal defects were well recovered even in the axilla.

Laser annealing is known as a short-time annealing technique, but in the case of laser annealing using coherent light, the annealing process occurs at the end of the contact window hole (4) due to the interference effect of the 5i02 film. becomes discontinuous stitches. However, in the annealing using the tungsten halogen lamp of the present invention, incoherent light (λ-0, 4 to 40μ
m), phenomena such as laser annealing are avoided.

In addition, in the processing method of the present invention, physical damage is removed when sputtering, milling, reactive ion etching, reactive ion milling, etc. are used as dry etching, and etching is removed when plasma etching is used. The adduct is removed by sublimation.

Effects of the Invention According to the present invention, since the semiconductor can be processed in a short time, it is possible to remove the released JAJ loss chains and contamination caused by dry etching without affecting the distribution of impurities that have already been formed. can do. Furthermore, since incoherent light is used in the annealing after dry etching, it is possible to avoid the problem of laser annealing where the annealing group becomes discontinuous in the M part of the window hole.

↑ 115 of the drawings. Figures 1A and B are cross-sectional views for explaining one embodiment of the processing method of the present invention. Figure 2 shows a semiconductor substrate that has been dry etched and then annealed using a halogen lamp in tungsten. +'t (9+) was measured by the Rutherford back scattering method.

Figure 1 Figure 2 Nayanshinru Soft Procedure Amendment 1. Display of the case 1982 Patent Application No. 75709 2, Title of the invention Method for processing semiconductor substrates 3, Person making the amendment Relationship to the case Patent applicant address 6-7-35, Kitashinyo, Tokyo Parts Ward Name ( 2]
81 Sony Corporation Representative Director Norio Ohga 5, date of amendment order: 6, 1939,
Number of inventions increased by amendment

Claims (1)

[Claims] A method for processing a semiconductor substrate, comprising the steps of dry etching the entire surface of the semiconductor substrate, and irradiating the main surface with a lamp beam.