JPH09190981A - Heat treatment device for wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent defects such as slip, etc., from occurring in a wafer and also, improve the equality of film thickness in film growth by CVD device and the equality of film quality by providing a heat treatment device which can heat and cool the center and the periphery of a wafer with roughly uniform property. SOLUTION: A lower heat equalizing plate 15 is provided within a treatment chamber demarcated by a quartz glass board, and a water w is placed on the lower heat equalizing plate 15, and the also an upper heat equalizing plate 16 is arranged apart above this wafer W. Here, a recess 18 is made at the center of this upper heat equalizing plate 16 thereby thinning it, and infrared rays are applied from the halogen lamps provided at the top and bottom of the treatment chamber so as to heat the wafer W.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer heat treatment apparatus used in a CVD apparatus or the like, and more particularly to a heat treatment apparatus capable of matching the temperature raising / lowering characteristics of a central portion of a wafer with the temperature raising / lowering characteristics of a peripheral portion. .

[0002]

2. Description of the Related Art In a CVD apparatus or the like, a wafer is heated by a heat treatment apparatus when forming a film on the wafer. As this kind of heat treatment apparatus, one using infrared rays shown in FIG. 4 is known. As shown in the figure, this heat treatment apparatus uses a transparent quartz glass plate 11 for processing chamber 10
And a plurality of rod-shaped halogen lamps 21 are arranged in parallel on the upper and lower sides of the processing chamber 10.
A lower heat equalizing plate 15 and an upper heat equalizing plate 16 are arranged inside the zero.

The lower heat equalizing plate 15 is made of a translucent material and is placed inside the processing chamber 10 by legs 15a. The lower soaking plate 15 also serves as a support base for the wafer W, and an accommodation recess 19 for accommodating the wafer W is formed on the upper surface. The upper heat equalizing plate 16 is made of a translucent material, and is provided above the lower heat equalizing plate 15 in parallel with the lower heat equalizing plate 15 by a leg 16a at a considerable distance.

In this heat treatment apparatus, the halogen lamp 21 emits light in the ascending step of heating the wafer W and the soaking plate 1
Wafer W is irradiated with infrared rays that pass through 5, 16 and 16, infrared rays that enter from the side of the gap between lower heat equalizing plate 15 and upper heat equalizing plate 16 and infrared rays that are radiated by heat equalizing plates 15 and 16, and The wafer W is maintained at a constant temperature in the processing steps such as film formation, and the wafer W is cooled in the subsequent temperature lowering step. That is, as shown in FIG. 5, in the temperature raising step, infrared rays transmitted through the upper heat equalizing plate 16 (light amount Q1), infrared rays incident from the side (light amount Q2), and secondary radiation with the upper heat equalizing plate 16 The wafer W is irradiated with infrared rays (light quantity Q3) and infrared rays (light quantity Q4) transmitted through the lower heat equalizing plate 15, and the wafers W are heated by these infrared rays Q1, Q2, Q3, Q4.

[0005]

However, in the above-mentioned conventional heat treatment apparatus, the temperature rising / falling characteristics of the wafer W are affected by the soaking plates 15, 16 and the like, so that the wafer W
It is difficult to uniformly raise and lower the temperature of the entire surface of the wafer W, and there is a problem that a partial difference in thermal history occurs in the wafer W.
That is, as shown in FIG. 6, the central portion of the wafer W has a low rate of temperature rise and a low rate of temperature decrease (in the figure,
However, conversely, the peripheral portion of the wafer W has a characteristic that the temperature rising rate and the temperature lowering rate are both high (solid line in the figure), and a thermal history difference is generated between the central portion and the peripheral portion of the wafer W. There was a problem.

The partial difference in the thermal history generated on the wafer W causes the defects of the wafer W such as slip due to thermal stress, and impairs the film thickness uniformity and the film quality uniformity during film formation by the CVD apparatus. To cause
The solution was strongly demanded. The present invention has been made in view of the above circumstances, and provides a heat treatment apparatus capable of heating the entire surface (all portions) of a wafer at a uniform rate of temperature increase and cooling at a uniform rate of temperature decrease. The purpose is to

[0007]

In order to achieve the above object, the present invention provides a soaking plate between a wafer and an infrared lamp, and the infrared rays emitted by the infrared lamp are passed through the soaking plate. In the wafer heat treatment device for irradiating the wafer with the above-mentioned wafer, a light amount control means is provided for increasing the amount of infrared light applied to the central portion of the wafer to be larger than that of the peripheral portion, and for promoting heat radiation from the central portion of the wafer. It was

The heat treatment apparatus according to the present invention is applied to a semiconductor manufacturing apparatus represented by a CVD apparatus, but can also be applied to various semiconductor manufacturing apparatuses for heating a wafer during a semiconductor wafer manufacturing process. As the infrared lamp, a lamp which emits infrared rays and a halogen lamp are used. One or more of the infrared lamps are arranged on the upper and lower sides of the wafer or on one of the upper and lower sides, and the arrangement is appropriately selected. The heat equalizing plate is made of a translucent material and is provided between the wafer and the infrared lamp.

The light quantity control means makes the thickness of the central portion of the heat equalizing plate thinner than that of the peripheral portion, or partially changes the light transmittance or the refractive index of the heat equalizing plate, or the peripheral portion of the wafer. This is achieved by providing a shade member that reduces the amount of incident infrared light between the infrared lamp and the wafer, or by providing a lens.

In the wafer heat treatment apparatus according to the present invention, when the wafer is heated, the central portion of the wafer is irradiated with infrared rays having a larger light quantity than that of the peripheral portion. When the temperature of the wafer is increased at a high temperature rate and the wafer is cooled, heat dissipation from the central portion of the wafer is promoted, so that the temperature of the central portion and the peripheral portion of the wafer are reduced at substantially the same temperature reduction rate. That is, the central portion of the wafer has a lower rate of temperature increase and the lower rate of temperature decrease than the peripheral portion (see FIG. 6 described above), but the wafer has a temperature lowering rate and a higher rate of heating at the central portion and the peripheral portion due to the light amount control means. Match. Therefore, the thermal history of the wafer can be matched over the entire surface, and defects such as slips can be prevented from occurring.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show a wafer heat treatment apparatus according to an embodiment of the present invention.
Is an enlarged schematic cross-sectional view of a main part, FIG. 2 is a diagram showing an irradiation light amount characteristic of infrared rays, and FIG. 3 is a diagram showing a temperature characteristic of a soaking plate. The same parts as those of the heat treatment apparatus shown in FIG. 4 described above are designated by the same reference numerals, and a part of them is not illustrated and described.

In FIG. 1, reference numeral 15 denotes a lower soaking plate which accommodates and holds a wafer W in a housing recess 19, and 16 denotes a lower soaking plate 1.
The upper soaking plates 15 and 16 are arranged in parallel to face the wafer W on the wafer 5, and the soaking plates 15 and 16 are housed in the processing chamber 10. The upper heat equalizing plate 16 has a recess 18 formed in a central portion thereof facing the central portion of the wafer W on the upper surface, and the thickness (t2) of the central portion is smaller than the thickness (t1) of the peripheral portion. The concave portion 18 forms a curved surface with a gentle peripheral portion.

In this embodiment, the upper soaking plate 1
In FIG. 6, a recess 18 is formed on the upper surface in order to reduce the thickness t2 of the central portion, but a recess is formed on the lower surface, or a recess is formed on both the upper surface and the lower surface to reduce the thickness of the central portion. It is also possible to plan. Further, in this embodiment, the upper heat equalizing plate 16 is made thin, but the lower heat equalizing plate 15 is made thin similarly to the upper heat equalizing plate 16, and both the lower heat equalizing plate 15 and the upper heat equalizing plate 16 are It is also possible to reduce the thickness. Furthermore, in this embodiment, the shape of the recess 18 is not particularly mentioned, but this shape can be arbitrarily selected. A lens effect, for example, infrared rays, may be focused on the central portion of the wafer W while the recess 18 is used to reduce the thickness.

In this embodiment, the lower heat equalizing plate 1
5, the wafer W is placed in the accommodation recess 19 of the processing chamber 10,
The wafer W is irradiated with infrared rays from the upper and lower sides of the wafer by the halogen lamp 21 (see FIG. 4). Then, in the temperature raising step, as described above, the wafer W is transferred to the upper soaking plate 16
Are heated by the infrared ray Q1 which passes through, the infrared ray Q2 which enters from the side, the infrared ray Q3 by the secondary radiation, and the infrared ray Q4 which passes through the lower heat equalizing plate 15.

Here, since the upper heat equalizing plate 16 has a recess 18 formed in the central portion and the central portion is thinned,
As shown in, the amount of light (the amount of light per unit area) Q1 ″ radiated to the central portion of the wafer W through the central portion of the upper heat equalizing plate 16 is equal to the amount of light radiated to the peripheral portion of the wafer W through the peripheral portion. 3, the heat capacity (per unit area) of the central portion of the upper soaking plate 16 is smaller than that of the peripheral portion, and the temperature of the central portion rises faster than that of the peripheral portion, as shown in FIG. The temperature rising characteristics of the central portion of the wafer W and the temperature rising characteristics of the peripheral portion can be made to substantially match.

During the cooling step after the treatment step, in other words, during cooling, as shown in FIG. 3, the heat capacity of the central portion of the upper soaking plate 16 is small and the temperature of the central portion is the temperature of the peripheral portion. More quickly than. Therefore, in the wafer W as well, the characteristics of the temperature drop in the central portion and the temperature drop in the peripheral portion substantially match. In FIG. 3, the solid line indicates the temperature characteristic of the central portion of the upper heat equalizing plate 16, and the broken line indicates the temperature characteristic of the peripheral portion.

As described above, in this embodiment, since the temperature raising / lowering characteristic of the temperature of the central portion of the wafer W and the temperature raising / lowering characteristic of the peripheral portion of the wafer W can be made to substantially coincide with each other, a defect such as a slip is generated. When used in a CVD apparatus, the film thickness uniformity and the film quality uniformity can be improved.

[0018]

As described above, according to the heat treatment apparatus for a wafer according to the present invention, the central portion and the peripheral portion of the wafer can be heated and cooled with substantially the same characteristics, and the wafer can be partially heated. Since it is possible to prevent a difference in thermal history, it is possible to prevent defects such as slip, and also to prevent CV
The effect that the uniformity of the film thickness and the uniformity of the film quality at the time of film formation in the D device can be improved is obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged schematic view of a main part of a wafer heat treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a graph showing a characteristic of an infrared irradiation light amount on a wafer in the heat treatment apparatus.

FIG. 3 is a graph showing temperature rising / falling characteristics of a soaking plate in the heat treatment apparatus.

FIG. 4 is a schematic view of a conventional wafer heat treatment apparatus.

FIG. 5 is an explanatory view schematically showing a path of infrared rays with which a wafer is irradiated in the conventional heat treatment apparatus.

[FIG. 6] Temperature rise of a wafer in the conventional heat treatment apparatus
It is a graph which shows a temperature drop characteristic.

[Explanation of symbols]

 10 Processing Chamber 15 Lower Uniform Plate 16 Upper Uniform Plate 18 Recessed 19 Recessed Housing 21 Halogen Lamp (Infrared Lamp) W Wafer

Claims (1)

[Claims] 1. A wafer heat treatment apparatus in which a soaking plate is provided between a wafer and an infrared lamp, and infrared rays emitted by the infrared lamp are applied to the wafer through the soaking plate. A heat treatment apparatus for a wafer, which is provided with a light amount control means for increasing the amount of infrared light applied to the central portion to be larger than that for the peripheral portion and for promoting heat radiation from the central portion of the wafer.