Method of manufacturing semiconductor substrate, method of manufacturing semiconductor device, and semiconductor device

Abstract

A method of manufacturing a semiconductor substrate includes: forming on a semiconductor base a first isolation layer for isolating an element region from another region; forming a first semiconductor layer on the semiconductor base; forming a second semiconductor layer on the first semiconductor layer, the second semiconductor layer having an etch selectivity less than that of the first semiconductor layer; forming a support hole by removing a portion of the second semiconductor layer and a portion of the first semiconductor layer each corresponding to the support hole; forming a support formation layer above the semiconductor base so as to cover the support hole and the second semiconductor layer; forming a support and an exposed surface for exposing part of an end of each of the first semiconductor layer and the second semiconductor layer by etching an area other than that including the support hole and the element region therein, the first semiconductor layer and the second semiconductor layer being located under the support; forming a cavity between the second semiconductor layer in the element region and the semiconductor base by etching away the first semiconductor layer through the exposed surface; forming a buried insulating layer in the cavity; and performing planarization above the second semiconductor layer to remove part of the support located on the second semiconductor layer; wherein the forming a support hole forms a first support hole at the boundary between the element region and the first isolation layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.

FIGS. 1A and 1B are schematic views showing a method of manufacturing a semiconductor substrate following the process flow of one embodiment of the invention; FIG. 1A is a schematic plan view showing the manufacturing method of a semiconductor substrate, and FIG. 1B a schematic sectional view showing the manufacturing method of a semiconductor substrate.

FIGS. 2A and 2B are schematic views showing the method of manufacturing a semiconductor substrate; FIG. 2A is a schematic plan view showing the manufacturing method of a semiconductor substrate, and FIG. 2B is a schematic sectional view showing the manufacturing method of a semiconductor substrate.

FIGS. 3A and 3B are schematic views showing the method of manufacturing a semiconductor substrate; FIG. 3A is a schematic plan view showing the manufacturing method of a semiconductor substrate, and FIG. 3B is a schematic sectional view showing the manufacturing method of a semiconductor substrate.

FIGS. 4A and 4B are schematic views showing the method of manufacturing a semiconductor substrate; FIG. 4A is a schematic plan view showing the manufacturing method of a semiconductor substrate, and FIG. 4B is a schematic sectional view showing the manufacturing method of a semiconductor substrate.

FIGS. 5A and 5B are schematic views showing the method of manufacturing a semiconductor substrate; FIG. 5A is a schematic plan view showing the manufacturing method of a semiconductor substrate, and FIG. 5B is a schematic sectional view showing the manufacturing method of a semiconductor substrate.

FIGS. 6A and 6B are schematic views showing the method of manufacturing a semiconductor substrate; FIG. 6A is a schematic plan view showing the manufacturing method of a semiconductor substrate, and FIG. 6B is a schematic sectional view showing the manufacturing method of a semiconductor substrate.

FIGS. 7A and 7B are schematic views showing the method of manufacturing a semiconductor substrate; FIG. 7A is a schematic plan view showing the manufacturing method of a semiconductor substrate, and FIG. 7B is a schematic sectional view showing the manufacturing method of a semiconductor substrate.

FIGS. 8A and 8B are schematic views showing the method of manufacturing a semiconductor substrate; FIG. 8A is a schematic plan view showing the manufacturing method of a semiconductor substrate, and FIG. 8B is a schematic sectional view showing the manufacturing method of a semiconductor substrate.

FIGS. 9A and 9B are schematic views showing the method of manufacturing a semiconductor substrate; FIG. 9A is a schematic plan view showing the manufacturing method of a semiconductor substrate, and FIG. 9B is a schematic sectional view showing the manufacturing method of a semiconductor substrate.

FIGS. 10A and 10B are schematic views showing a method of manufacturing a semiconductor device and a configuration of the semiconductor device; FIG. 10A is a schematic plan view and FIG. 10B is a schematic sectional view.

FIGS. 11A and 11B are schematic views showing a conventional method of manufacturing a semiconductor substrate; FIG. 11A is a schematic plan view and FIG. 11B is a schematic sectional view.

Claims

1. A method of manufacturing a semiconductor substrate, comprising: forming a first isolation layer for isolating an element region from another region on a semiconductor base;forming a first semiconductor layer on the semiconductor base;forming a second semiconductor layer on the first semiconductor layer, the second semiconductor layer having an etch selectivity less than an etch selectivity of the first semiconductor layer;forming a support hole by removing a portion of the second semiconductor layer and a portion of the first semiconductor layer each corresponding to the support hole;forming a support formation layer above the semiconductor base so as to cover the support hole and the second semiconductor layer;forming a support and an exposed surface for exposing part of an end of each of the first semiconductor layer and the second semiconductor layer by etching an area other than an area including the support hole and the element region therein, the first semiconductor layer and the second semiconductor layer being located under the support;forming a cavity between the second semiconductor layer in the element region and the semiconductor base by etching away the first semiconductor layer through the exposed surface;forming a buried insulating layer in the cavity; andperforming planarization above the second semiconductor layer to remove part of the support located on the second semiconductor layer;wherein the forming a support hole forms a first support hole at a boundary between the element region and the first isolation layer.

2. A method of manufacturing a semiconductor substrate, comprising: forming on a semiconductor base a first isolation layer for isolating an element region from another region and forming within the element region a second isolation layer for being used as a stopper layer;forming a first semiconductor layer on the semiconductor base;forming a second semiconductor layer on the first semiconductor layer, the second semiconductor layer having an etch selectivity less than an etch selectivity of the first semiconductor layer;forming a support hole by removing a portion of the second semiconductor layer and a portion of the first semiconductor layer each corresponding to the support hole;forming a support formation layer above the semiconductor base so as to bury the support hole and to cover the second semiconductor layer;forming a support and an exposed surface for exposing part of an end of each of the first semiconductor layer and the second semiconductor layer by etching an area other than an area including the support hole and the element region therein, the first semiconductor layer and the second semiconductor layer being located under the support;forming a cavity between the second semiconductor layer in the element region and the semiconductor base by etching away the first semiconductor layer through the exposed surface;forming a buried insulating layer in the cavity; andperforming planarization above the second semiconductor layer by using at least the second isolation layer to remove part of the support located on the second semiconductor layer;wherein the forming a support hole forms a first support hole at a boundary between the element region and the first isolation layer.

3. The method of manufacturing a semiconductor substrate according to claim 2, wherein the forming a support hole forms a second support hole in an area including the second isolation layer.

4. The method of manufacturing a semiconductor substrate according to claim 1, wherein: the first semiconductor layer is a silicon germanium layer; andthe second semiconductor layer is a silicon layer.

5. A method of manufacturing a semiconductor device, comprising forming a transistor in the second semiconductor layer after performing the method of manufacturing a semiconductor substrate according to claim 1.

6. A semiconductor device having an SOI structure comprising: a buried insulating layer formed on a semiconductor base, the buried insulating layer being buried to replace a first semiconductor layer;a second semiconductor layer formed on the buried insulating layer;a support for supporting the second semiconductor layer; anda first support hole for forming the support formed at a boundary of an element region and a first isolation layer.