Semiconductor device and method for manufacturing multilayered substrate for semiconductor device
A method for manufacturing a multilayered substrate for a semiconductor device, as well as a semiconductor device, is provided, the multilayered substrate exhibiting an excellent thermal conduction property and an excellent heat spreading effect without occurrence of warp and deformation. A diamond layer is formed through vapor phase deposition on one principal surface of a first silicon substrate by a CVD method. A SiO 2 layer is formed on this diamond layer. A SiO 2 layer is formed on a surface of a second silicon substrate by a thermal oxidation method. The diamond layer is bonded to the second silicon substrate with SiO 2 layers disposed on both the diamond layer and the second silicon substrate therebetween. The first silicon substrate is removed by dissolution through etching to expose the surface of the diamond layer. A silicon layer serving as a semiconductor layer is formed on the diamond layer by a CVD method.
1. A method for manufacturing a multilayered substrate for a semiconductor device comprising:
forming locally a diamond layer on a first silicon substrate;
forming an amorphous silicon layer on the diamond layer and the first silicon substrate and forming a silicon oxide layer on a second silicon substrate;
bonding the diamond layer to the second silicon substrate with the amorphous silicon layer and the silicon oxide layer therebetween;
removing the first silicon substrate by polishing while the polishing treatment is stopped when a surface of the diamond layer is exposed partially;
removing the amorphous silicon layer by etching with an alkali solution through using the silicon oxide layer as a stop layer;
removing the silicon oxide layer by etching with an solution containing hydrofluoric acid thereby forming locally a multilayered film composed of the silicon oxide layer, the amorphous silicon layer, and the diamond layer on the second silicon substrate; and
forming a semiconductor layer on the diamond layer that is the uppermost layer of the multilayered film and on the region where the multilayered film is not present on the second silicon substrate.
2. The method for manufacturing a multilayered substrate for a semiconductor device according to claim 1 , wherein:
the first silicon substrate is removed by polishing through the use of a liquid in which colloidal silica is mixed into an amine based aqueous solution so as to expose a surface of the diamond layer; or
the second silicon substrate is coated with silicon nitride (SiN) and, thereafter, the first silicon substrate is removed by being dissolved into a hydrofluoric acid based solution so as to expose a surface of the diamond layer.
3. The method for manufacturing a multilayered substrate for a semiconductor device according to claim 1 , wherein the diamond layer is bonded to the second silicon substrate by thermal compression bonding.
4. The method for manufacturing a multilayered substrate for a semiconductor device according to claim 1 , wherein the diamond layer is formed from electrically conductive diamond doped with a dopant.
5. The method for maufacturing a multilayered substrate for a semiconductor device according to claim 1 , wherein the semiconductor layer is a silicon layer, and an element is formed on the semiconductor layer.