JPH034035Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a so-called sample holder, which is a support on which a semiconductor substrate is placed, which is convenient when processing a semiconductor substrate by changing the temperature, for example.

Conventional configuration and its problems For example, in an ion implanter, semiconductor substrates with different diameters can be freely installed, and even if the outer diameter and thickness of the sample semiconductor substrates differ, each time the sample is loaded, As a sample holder that eliminates the inconvenience of replacing the sample holder, there is one shown in the plan view and cross-sectional view of FIGS. 1a and 1b.

That is, as shown in FIG.
Further, during the ion implantation operation, the sample 5 can be held by being supported by the canopy-like protrusion 4 of the base 1.

However, when processing a semiconductor (e.g., silicon) wafer 5 at high temperatures in this sample holder, if the wafer is covered with an oxide film, the top surface will warp in a concave shape, and the outer periphery of the wafer will warp. It is known that when the semiconductor wafer reaches the wafer, the outer periphery hits the eave-shaped protrusion 4 of the base 1, and that stress causes cracks in the semiconductor wafer. Therefore, as the diameter of a semiconductor wafer to be heat-treated increases to 5 or 6 inches, the warpage cannot be ignored, and as a result, the wafer may be damaged within the sample holder.

Purpose of the Invention The present invention improves this point and provides a substrate support that deforms in accordance with the warpage of the wafer at high temperatures.

Structure of the invention In summary, the present invention provides a recess capable of accommodating the semiconductor substrate on one surface of a base that supports the semiconductor substrate in a planar manner, and a large-diameter annular groove on the circumferential side of the recess. This is a substrate support in which a layer of a substance with a low coefficient of thermal expansion is provided on the side surface so that one surface side of the base can be bent into a concave shape when heated, thereby preventing warping during heat processing of semiconductor wafers. In addition, the substrate support itself can be warped, and the wafer will not be damaged.

DESCRIPTION OF EMBODIMENTS FIGS. 2a and 2b show a plan view and a sectional view of a substrate support according to the present invention. A sample holder 6 for supporting a substrate formed of polysilicon as a base material is covered with a silicon dioxide film 7 on its surface, and has a recess for holding a semiconductor substrate 8 and an eaves portion 9 for supporting the sample 8. FIG. 3 is a sectional view showing the warping state when the semiconductor substrate 8 is placed in the recess and the substrate support 6 is held at a high temperature. As an example, if the substrate to be processed is a 4-inch diameter silicon wafer with a silicon dioxide film on one main surface, the film thickness ratio between the polysilicon holder base 6 and the silicon dioxide film 7 is as follows:
By forming the ratio of 200 to 450 to 1, the warped states of the substrate 8 to be processed and the holder base 8 could be matched.

It should be noted that even if the warpage of the substrate 8 to be processed is small, the warpage in both cases hardly hits the eaves, and the mechanical damage caused is extremely small.

Effects of the invention According to the invention, by forming a material with a small coefficient of thermal expansion on the surface of the concave side of the base of the holder, that is, the substrate support, suitable for wafers of various diameters, a silicon dioxide film can be formed on the surface. Even if a silicon wafer is subjected to high-temperature processing while being placed on the substrate support itself after normal ion implantation processing, it is possible to maintain the warpage in the same direction as the wafer to be processed. It does not damage the wafer.

[Brief explanation of drawings]

Figures 1a and 1b are plan views of conventional examples of substrate supports;
A sectional view, FIGS. 2a and 2b are plan views of the embodiment of the present invention,
FIG. 3 is a cross-sectional view of the substrate support according to the embodiment of the present invention. 2...Plate-shaped recessed portion, 6...Substrate support, 7...
...Oxide film, 8...Semiconductor wafer.

Claims (1)

[Scope of utility model registration request] A recess capable of accommodating and supporting the semiconductor substrate and a large-diameter annular groove on the circumferential side of the recess are provided on one surface of the base that supports the semiconductor substrate planarly, and a thermal expansion coefficient is provided on the surface on the recess side. 1. A substrate support, which is provided with a coating layer of a substance having a small amount, so that one surface side of the base can be bent into a concave shape when heated.