JPS58194332A - Heating method of semiconductor with irradiation of light - Google Patents

Abstract

PURPOSE:To suppress the damage like a slip line through heating of semiconductor wafer with irradiation of light by auxiliarily heating the area near the circumference of wafer or preheating it after arranging the auxiliary heating source of the self heating type such as halogen bulb or molybdenum heater in such a way as surrounding the circumference of semiconductor wafer. CONSTITUTION:As an auxiliary heating source 2, a halogen bulb or infrared bulb consisting of an oblong quartz glass. Such heating source is provided with a filament 2b which is arranged like a ring in such a way as surrounding the circumference 1c of the wafer 1 and also provides, to and from the quartz hooks 2a in order to support the wafer 1. At the time of heating wafer by irradiation of light, the heating source 2 is turned ON in view of auxiliarily heating the area near the circumference 1b of wafer. Thereby, temperature difference between the center 1a and the area near the circumference 1b becomes small and the wafer can be heated without generating damage like a slip line etc. As a heating source 2, a metal resistance heat generating body like a molybdenum heater which provides an output as a result of self heat generation in accordance with power consumption may be used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of heating a semiconductor wafer by light irradiation.

Recently, as a method for introducing impurities into semiconductor wafers (hereinafter referred to as wafers), ion implantation has been developed, in which the impurities are accelerated into ions and implanted into the wafer in order to precisely control the impurity concentration and junction depth. It is being used. However, in this ion implantation method, 100Or
wafers need to be heat-treated for a longer period of time.

In that case, the heat treatment must be performed in a short time so that the depth distribution of the implanted impurities does not change due to thermal diffusion. Furthermore, rapid heating and cooling of wafers is required for rounding to improve productivity.

In response to the above request, a method has recently been developed that heats wafers with a force of 1000 C in a few seconds.
It is possible to increase knitting up to 1400C for a short time.

However, when a wafer, for example single crystal silicon, is heated to over 1ooot:' within a few seconds, damage called "slip line" occurs due to the difference in temperature rise between the wafer's outer periphery and the center, that is, the rounding of uneven temperature rise. I found out. In other words, the thickness of the wafer is usually 05m before fIk
The temperature distribution on the wafer surface is very thin, and the humidity distribution in the thickness direction is alleviated in about 10 seconds, so in practical terms, it is necessary to even the temperature distribution on the wafer surface, such as with a slip line. However, if the surface of the wafer is irradiated with light at a uniform irradiation energy density, the heat dissipation from the wafer's outer periphery is greater than that from the center, so the temperature near the wafer's periphery is lower than the center. The temperature will be lower than the normal temperature, and a slip line will occur.

From this perspective, the present invention has been made with the object of providing a heating method for heating semiconductor wafers by light irradiation that does not cause damage such as slip lines. A self-heating auxiliary heating source such as a molybdenum heater is arranged so as to surround the outer periphery of the semiconductor wafer, and the auxiliary heating source is used to supplementally heat the vicinity of the periphery of the semiconductor wafer. The purpose of this method is to heat the semiconductor material by irradiating it with light.

An embodiment of the present invention will be described below with reference to the drawings.

Figure 1 is an explanatory diagram of a heating method for wafers placed in a light irradiation furnace, viewed from above. The light is irradiated so that the surface temperature of 1 becomes approximately 12501:' at the central portion 1α. The total power consumption of the surface light source for light irradiation is about 35 yen, and the wafer is ion-implanted 4-inch diameter single-crystal silicon.

2 is a long halogen 1 made of quartz glass! It is a sphere or an infrared light bulb, and is equipped with a filament 26 and is arranged in a ring shape so as to surround the outer IC of the wafer 1, and has quartz claws 2α supporting the Ueno-1 here and there. It is equipped with The inner diameter d of the ring is approximately 11D1
Since it is about 1, the gap t with Ueno-1 is approximately 4ml! degree. Then, when heating the wafer by light irradiation, the upper distribution lamp is turned on with a power consumption of about 920W, and if the area near the outer periphery 1b of the wafer is heated auxiliaryly, the temperature of the central part 1α of 1250t:' K is increased. Near the outer periphery 16 is 125
5t: 8 degrees Celsius, the temperature near the outer periphery 1b is a little higher, so the sea urchin can be heat-treated without any damage such as slip lines. In the above case, when light irradiation heating is performed without supplementary heating, 1f near the outer periphery 1b becomes a considerably low value of about 1120C, and damage such as slip lines is observed9.

As can be understood from the above embodiments, the present invention provides an auxiliary heat source for the outer periphery 1b of the wafer so as to surround the outer periphery IC with one auxiliary heating source so as to offset the temperature drop due to heat dissipation from the outer periphery 16. This method attempts to prevent the occurrence of slip lines by heating the wafer to a uniform temperature by reducing the temperature difference between the center and the vicinity of the outer periphery and making the temperature uniform over the entire surface of the wafer.

However, since wafer heating by light irradiation is generally carried out in an inert gas atmosphere such as argon or in a vacuum, the auxiliary heating source is not limited to a light bulb ME, but also a metal heater such as a molybdenum heater. A resistive heating element may be used, and the output of the auxiliary heating source may be one that self-heats according to its power consumption.

The present invention is based on the method described above and the method of heating semiconductor wafers I. Improving the uniformity of temperature distribution on the wafer surface by heating the semiconductor wafer with light irradiation while supplementally heating the vicinity of the outer periphery of the semiconductor wafer with a heat source, or by heating the semiconductor wafer preliminarily with light irradiation. However, it suppresses damage such as slip lines, and has extremely great practical value.

[Brief explanation of the drawing]

FIGS. 1 and 2 are explanatory diagrams of a wafer placed in a light irradiation furnace, and 1#:t ueno.-12 indicates a supplementary heat source. Patent Applicant's Inn Figure (self f-) Proceedings Amendment Written December 2, 1930, Director General of the Patent Office, Arashi 1, Mr. Ju, -41 1, Indication of the Case, 1972, 11 Fees, 1st Q' L-Dakupu No. 2, Name of the invention: 1. Heated by Koshoji (3 pieces, 5 comparisons 3, Relationship with the person making the amendment case) γS! + Applicant's address: 2-chome, Otemachi, Chiyoda-ku, Tokyo No. 6 No. 1 Asahi Tokai Building 191 Old 4, Ne So and l 毫K l Ha Added 13 Sac Mei's dinner destination, subject of correction (+) Sai 4I31i* ¥8R')t! j:lit
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Claims (1)

[Claims] In a method of heating a semiconductor wafer by light irradiation, an auxiliary heating source that generates self-heating, such as molybdenum heat in a halogen bulb, is placed so as to surround the periphery of the semiconductor wafer, and the auxiliary heating source is used to auxiliarily heat the vicinity of the periphery of the semiconductor wafer. A method of heating the semiconductor wafer 1- by light irradiation while heating or auxiliary heating.