JPS63269543A - Soaking stage of heat pipe system - Google Patents

Abstract

PURPOSE:To keep a temperature distribution on a heating face uniform by a method wherein an inner side of a container at a face where a trapezoid-shaped container is to be soaked is used as a working-liquid condensation face and pyramid-shaped protrusions or cone-shaped protrusions of a specific size are formed densely on the whole face. CONSTITUTION:An inner side of a container 1 is used as a working-liquid condensation face 2; pyramid-shaped protrusion or cone-shaped protrusions are formed there. It is desirable that these protrusions are shaped to be quadrangular pyramids or triangular pyramids 4; a length of one side at a base of these pyramids is to be 2-20 mm and their height is to be 2-20 mm. If the length of the side at the base and the height are less than 2 mm, a condensed liquid film spaces between the protrusions and a liquid film is formed on a condensed face. It is desirable that an area of the condensation face 2 is to be 20-600 cm<2>; if it is less than 20 cm<2>, the condensation face does not function as a soaking stage; if the area exceeds 300 cm<2>, highly accurate uniformity becomes difficult. A working liquid can be selected according to the purpose of use; naphthalene can be used for evaluation of an inspection of a gallium arsenide semiconductor wafer; as a material for the container, stainless steel is to be used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a heat pipe type soaking table used in the inspection and evaluation process of gallium-arsenide semiconductor wafers.

[Problems to be solved by the prior art and the invention] In heating substances, uniformity of humidity on the heating surface is often a problem. That is, it is clear that if there is local variation in the temperature of a heating surface having a certain area, this will directly lead to unevenness in the quality of products manufactured using the heating surface.

Generally, a method has been used in the past in which the metal plate is directly heated with a heater or the like. In this case, it goes without saying that the surface temperature varies to some extent, but in the conventional technical field, highly accurate uniformity was not required. However, in the inspection and evaluation process of gallium-arsenide semiconductor wafers, which has been rapidly developed in recent years, the heating surface temperature must be kept at ±1°C.
Therefore, the demand for high-precision soaking tables has become extremely large.

Under these circumstances, methods have been developed in which a heat pipe is used to connect the soaking table and the heating source, and a method in which the soaking table itself is made into a heat pipe. Even with this arrangement, it is impossible to control the surface temperature to ±1°C.

Furthermore, in the latter case, before the condensate on the heat pipe condensing surface drips, a liquid film is formed that is unevenly distributed on the condensing surface, which has the disadvantage that the temperature distribution varies to some extent.

(Means for Solving the Problems) In view of this, the present invention has been developed as a result of various studies and has developed a heat pipe-type soaking table having highly accurate temperature uniformity required in the field of advanced technology. By evacuating the inside and sealing the working fluid, it is made into a pipe, and one of the bottoms of the container is used as a condensing surface for the working fluid to perform uniform heating, and a pyramid is placed inside the container on the condensing surface. Alternatively, it is characterized by densely provided conical protrusions over the entire surface.

[For production]

By using the inside of the trapezoidal container, which is the surface for uniform heating, as the working fluid condensation surface, and by providing pyramidal or conical projections densely over the entire surface, the condensed liquid is distributed uniformly over the entire surface. It becomes like this. As a result, the temperature distribution on the heating surface can be maintained uniformly, and temperature variations can be kept within ±1°C.

The truncated container may be any truncated container, but it is preferable to use a truncated pyramid or a truncated cone from the viewpoint of use. One of the bottoms of the container should be the heating surface, and the inside of the container should be the condensing surface for the working fluid. A pyramid or conical protrusion is provided as a base. It is desirable to use a square or triangular protrusion for processing purposes, and the length of one side of the base should be 2 to 20 #1, and the height should be 2.
~20m. This is because if the length and height of the bottom of the protrusion are less than 2mm, the condensate will fill between the protrusions and form a liquid film on the condensation surface. This is because if each exceeds 20 Mn, the distribution of the condensate becomes macro-dimensional and becomes meaningless.

The size of the condensing surface is preferably 20 to 600 cIi, because if it is less than 2OC, it will not be able to function as a soaking table, and if it exceeds 600 crA, it will be difficult to achieve high-precision uniformity. The working fluid may be selected depending on the purpose of use, but naphthalene is used for inspection and evaluation of gallium-arsenide semiconductor wafers, and stainless steel is used as the material for the container. Further, in order to prevent distortion of the heat-uniforming surface due to an increase in internal pressure, it is preferable to provide a support between the bottom surfaces of the container.

(Example) Figures 1 and 2 show an example of the soaking table of the present invention.
m, diameter of one bottom surface 130 m.

A truncated conical hollow container with a diameter of 82 mm on the other bottom surface is shown, and one bottom surface of the container (1) with a diameter of 130 mm is placed on a soaking surface (2
), attach the bottom of the 82InIn diameter to the heating source mounting surface (3
). Inside the container (1) on the soaking surface (2), square pyramid-shaped protrusions (4) with a side of 188 cm and a height of 5 m on the bottom are densely arranged to encourage condensation of the working fluid and downward flow of the fluid. This prevents the condensate from being concentrated locally on the surface or from forming pools on the outer periphery.

Between the heating source mounting surface (3), that is, the bottom surfaces of the container, a strut (5) is provided to prevent the heating surface (2) from being distorted due to an increase in internal pressure. ) are provided with ports I to (6) for attaching the heater.

In addition, a working fluid injection and vacuum sealing tube (7) is attached to the hollow container (1), the inside is evacuated and naphthalene is sealed, a heater is attached to the heat source mounting surface (3), and a gallium-arsenide semiconductor wafer is I made a soaking table.

Regarding this, the temperature of the soaking table was set to 200° C. or higher, and the temperature distribution on the soaking surface was examined. As a result, the temperature distribution on the heating surface could be kept within ±1°C. For comparison, a soaking table of the same size without any projections formed on the inside of the container on the heating surface was prepared, and the temperature distribution on the heating surface was similarly investigated. As a result, the temperature distribution of the soaking table with no protrusions formed on the inside of the container on the soaking surface was ±10'C.

〔Effect of the invention〕

As described above, according to the soaking table of the present invention, the temperature of the object to be inspected is ±1°C in the inspection and evaluation process of gallium-arsenide semiconductor wafers, etc.
This method enables highly accurate soaking and greatly contributes to improving the quality of gallium-arsenide semiconductor wafers, which has significant industrial effects.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing one embodiment of the soaking table of the present invention;
The figure is a sectional view taken along the line AA' in FIG. 1. (1) Table-shaped container (2) Heating surface (3) Heating source mounting surface (4) Square hook-shaped projection (5) Support column (6) Bolt (7) Vacuum sealed tube

Claims (6)

[Claims] (1) A heat pipe is created by evacuating the inside of a table-shaped container and sealing the working fluid, and on a table where one of the bottoms of the container is used as a condensing surface for the working fluid to uniformly heat the container, the container is placed on the condensing surface. A heat pipe type soaking table characterized by having pyramidal or conical projections densely provided on the inside of the entire surface. (2) The heat pipe type soaking table according to claim 1, in which a truncated pyramid or truncated cone shaped container is used as the truncated container. (3) The shape of the protrusion on the condensation surface is a square pyramid or triangular pyramid, and the length of one side of the base is 2 to 20 mm and the height is 2 to 20 m.
A heat pipe type soaking stand according to claim 1 or 2, wherein m is defined as claim 1 or 2. (4) The heat pipe type soaking table according to claim 1, 2, or 3, wherein the area of the working fluid condensation surface is 20 to 600 cm^2. (5) Claim 1 in which naphthalene is used as the working fluid
The heat pipe type soaking table according to item 1, 2, 3, or 4. (6) Claims 1, 2, 3, and 4 in which a support column is provided between the condensation surface and the other bottom surface in the container to prevent deformation of the condensation surface due to thermal strain. Or the heat pipe type soaking table described in item 5.