JPH0418197Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a substrate cooling pad provided in a cooling device for substrates such as silicon wafers used in semiconductor manufacturing.

(Prior art) Conventionally, in a vacuum chamber, ions were implanted into this type of substrate to change the physical properties of its surface.
However, since there is a risk that the substrate or the resist coated on the substrate may be damaged due to temperature rise due to heat incidence, the flatness of the cooling plate that circulates cooling water over the substrate is Alternatively, it is cooled by being brought into contact with a lens-shaped raised front surface. In this case, the contact area with the cooling plate is reduced due to the unevenness on the back surface of the substrate, so a highly elastic thermally conductive rubber such as silicone rubber is provided on the front surface of the cooling plate, and the The board is pressed against the cooling plate using a clamp.

(Problem to be solved by the invention) When a thermally conductive rubber is provided on the cooling plate, a large amount of gas is generated from the rubber during processing of the substrate in the vacuum chamber, causing the vacuum chamber to become dirty and the vacuum to be poor. Moreover, the thermal conductivity of the rubber is 1 to 8×.
10 ^-3 w/cm・K, and the contact area with the substrate is extremely small, so the cooling efficiency is low, and when a large amount of power is required to process the substrate, as is the case in recent years, the substrate temperature will rise. Thermal conductive rubber is not suitable for use because it may cause damage to the resist or damage the substrate.

The object of the present invention is to provide a pad that releases less gas in a vacuum and has good cooling performance.

(Means for solving the problem) In the present invention, a substrate to be subjected to ion implantation or other processing in a vacuum chamber is brought into contact with the front surface of a cooling plate cooled by circulation of cooling water etc. via a pad. ,
In order to cool the substrate whose temperature increases with the processing, the pad is made of a laminate of Al or other metal thin films.

(Function) A substrate such as a silicon wafer is brought into contact with the front surface of a cooling plate through a pad, and when the substrate is subjected to, for example, ion implantation in a vacuum chamber and generates heat, the heat flows from the pad to the cooling plate. .

If this heat flow is poor, the temperature of the substrate will rise, causing damage or resist deterioration, but in the present invention, the pad is made of a laminate of thin metal films such as Al and Cu, so it is heat conductive. The pad surface has a significantly higher smoothness than rubber, and since it is a laminate, it has excellent ability to follow the warpage of the board when a load is applied to it, and the contact area with the board is also small. becomes larger. As a result, cooling efficiency is increased, and less gas is generated from the pads.
No substrate contamination.

(Example) To explain the example of the present invention with reference to the drawings, the first example is as follows.
In the figure, 1 is a substrate such as a silicon wafer that is brought into contact with the front surface of a cooling plate 3 provided in a vacuum chamber 2 via a pad 4, and the substrate 1 is subjected to, for example, ion implantation processing. . This process increases the temperature of the substrate 1, which may damage the substrate 1 or deteriorate the resist applied to it. Therefore, the cooling plate 3 is cooled by a cooling pipe 5 through which cooling water is circulated. ,
The substrate 1 is cooled via the pad 4.

Since the substrate 1 is brought into contact with the pad 4 on the front surface of the cooling plate 3 which is flat or protruded into a lens shape by the clamp 6, it comes into contact with the relatively uneven back surface of the substrate 1 with a large contact area. Since the pad 4 is made of a laminate of metal thin films such as Al or Cu, it has good thermal conductivity, and since there is little gas released from the pad 4 into the vacuum chamber 2, there is little dirt inside the vacuum chamber 2.

When the pad 4 is formed of a metal thin film of Al, its thermal conductivity is 2.0w/cm・K, and the pad is made of a 15μm thick film.
When 8 layers of Al thin films are stacked to form a pad,
As shown by curve A in Figure 2, even if the power for ion implantation is increased, the temperature rise of the substrate 1 is smaller than when silicone rubber pads shown in curves B, C, and D are used, resulting in good cooling. It worked.
The pad 4 made of Cu has a thermal conductivity of 3.9w/cm·K, which provides an even better cooling effect.

(Effects of the invention) As described above, according to the invention, the pad interposed between the substrate and the cooling plate is composed of a laminate of metal thin films, which maintains a large contact area with the substrate and improves cooling efficiency. Since there is little gas released into the vacuum chamber, there is less contamination of the chamber and the substrate, and the device is particularly effective as a cooling pad for high current density ion implanters.

[Brief explanation of the drawing]

FIG. 1 is a cutaway side view of an embodiment of the present invention, and FIG. 2 is a temperature diagram of the substrate. 1...Substrate, 2...Vacuum chamber, 3...Cooling plate, 4
... Patsudo.

Claims (1)

[Scope of utility model registration request] A substrate to be subjected to ion implantation or other processing in a vacuum chamber is brought into contact with the front surface of a cooling plate, which is cooled by circulation of cooling water, through a pad, to cool the substrate whose temperature increases due to the processing. A substrate cooling pad comprising a laminate of Al or other metal thin film.