JPH0228248B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an apparatus for cooling a substrate such as a silicon wafer used in the manufacture of semiconductors.

(Prior art) Conventionally, when performing ion implantation or other processing on this type of substrate in a vacuum chamber, there is a risk of heat generation and damage to the substrate, so the substrate was cooled by being held in a substrate holder that circulated cooling water. However, the substrate is easily deformed by heat, and if it loses contact with the substrate holder, the cooling performance deteriorates and cracks occur in the substrate, so the surface of the substrate holder is A cushion member made of silicone rubber covered with a thin film of polytetrafluoroethylene is provided, and by bringing the substrate into contact with this cushion member, the substrate is prevented from separating due to deformation and cooling performance is maintained.

(Problem to be solved by the invention) When large currents and high voltages are used for ion implantation processing of substrates as in recent times, the amount of heat generated by the substrate increases, and the heat flux decreases to 1w/cm ^2. When the contact heat transfer coefficient and thermal conductivity reach a certain level, it becomes difficult to cool the substrate with a cushion member made of silicone rubber covered with a thin film of polytetrafluoroethylene, which has poor contact heat transfer coefficient and thermal conductivity. During the ion implantation process, the temperature of the silicon substrate is preferably cooled to around 100°C.

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly durable cooling device that is suitable for cooling substrates that are processed under conditions that generate a large amount of heat.

(Means for Solving the Problems) In the present invention, a substrate to be processed in a vacuum chamber is held by a substrate holder cooled by circulation of cooling water through a cushion member. The cushion member is made of an elastomer mixed with powder or fibers of metal, carbon, etc., and a thin metal film is formed on the surface of the cushion member that comes into contact with the substrate.

(Function) The substrate is held in a substrate holder via a cushion member, and is subjected to treatments such as ion implantation in a vacuum chamber. The cushion member is made of powder or fibers mixed with the substrate, and a thin metal film with good thermal conductivity is formed on the surface of the cushion member that comes into contact with the substrate. The heat is transmitted to the cooled substrate holder via the thin film and the cushion member mixed with powder or fibers of metal, carbon, etc., and the substrate is cooled well.

(Example) To explain the example of the present invention with reference to the drawings, the first example is as follows.
In the figure, reference numeral 1 denotes a substrate holder disposed within a vacuum chamber 2. The substrate holder 1 is made of metal such as Cu or Al, and a cooling water circulation path 3 is provided inside thereof.

Reference numeral 4 denotes a cushion member provided on the surface, that is, the cooling surface, of the holder 1, and a thin metal film 6 is formed on the surface that comes into contact with a substrate 5 such as a silicon wafer.

The substrate 5 is placed on the cushion member 4 on which the metal thin film 6 is formed, is pressed against the pusher 7, and is held by the substrate holder 1.

The cushion member 4 is composed of an elastomer 8 such as silicone rubber mixed with a powder 9 of metal such as Al, carbon, etc. as shown in FIGS. 1 and 2, or fibers 9 as shown in the third diagram. . In this case, the fibers 9 may be long fibers or short fibers, and the fibers 9 may be long fibers or short fibers.
As shown in the figure, the fibers may be intertwined in a fluffy manner, and the fibers themselves may also have elasticity. The mixing ratio of the powder 9 or the fibers 9 is 5 to 95% by weight, the shore hardness of the cushion member 4 is about 20 to 80, and the thermal conductivity is 2 to 2 of that of the elastomer 8 alone. It is preferable to make it about 10 times as large.

The metal thin film 6 may be a single-layer film of Al, a two-layer film in which a film of Cu, Ag, etc. is formed on a film of Cr or Ti, or a three-layer film in which a film of Ni, etc. is formed on the two-layer film. , etc. These films can be formed by physical thin film forming means such as vacuum evaporation, sputtering, ion plating, etc., or chemical thin film forming means such as plating, for example. Formed to a thickness of 1 to 100 microns. The metal thin film 6 effectively transfers heat from the substrate 5 to the cushion member 4, prevents the fibers 9 from protruding from the elastomer 8, and also functions to reduce the amount of gas released from the elastomer 8. Incidentally, the metal thin film 6 may be constituted by a four-layer film in which an organic film is applied on the three-layer film as necessary.

The heat generated during the ion implantation process of the substrate 5 is caused by the metal thin film 6 which is a good thermal conductor and the cushion member 4 which is a good thermal conductor.
Since the temperature of the substrate 5 is smoothly transmitted to the cooled substrate holder 1 through Since it has elasticity, the closeness with the substrate 5 is improved and the cooling performance is accordingly improved.

(Effects of the Invention) According to the present invention, the substrate is held by the substrate holder via the cushion member formed with a thin metal film with good thermal conductivity, so that the metal thin film can be changed according to the deformation of the substrate. The cushion member is deformed and the substrate can be brought into constant contact with the cushion member, resulting in improved cooling performance and good elasticity.

[Brief explanation of drawings]

FIG. 1 is a cutaway side view of an embodiment of the present invention, FIG. 2 is an enlarged view of the main part thereof, and FIG. 3 is an enlarged view of the main part of another embodiment of the invention. DESCRIPTION OF SYMBOLS 1...Substrate holder, 2...Vacuum chamber, 4...Cushion member, 5...Substrate, 6...Metal thin film, 8...
...Elastomer, 9...Powder or fiber of metal, carbon, etc.

Claims (1)

[Claims] 1. In a device in which a substrate to be processed in a vacuum chamber is held in a substrate holder cooled by circulation of cooling water through a cushion member, the cushion member is coated with an elastomer containing powder of metal, carbon, etc. 1. A cooling device for a substrate, characterized in that the cushion member is made of a material mixed with fibers, and a metal thin film is formed on the surface of the cushion member that comes into contact with the substrate.