US 7,320,929 B2
Method of fabricating SOI wafer
Hiroji Aga, Annaka (Japan); and Kiyoshi Mitani, Annaka (Japan)
Assigned to Shin-Etsu Handotai Co., Ltd., Tokyo (Japan)
Appl. No. 10/522,413
PCT Filed Jul. 16, 2003, PCT No. PCT/JP03/09007
§ 371(c)(1), (2), (4) Date Jan. 26, 2005,
PCT Pub. No. WO2004/012268, PCT Pub. Date Feb. 05, 2004.
Claims priority of application No. 2002-219308 (JP), filed on Jul. 29, 2002.
Prior Publication US 2006/0040469 A1, Feb. 23, 2006
Int. Cl. H01L 21/30 (2006.01); H01L 21/46 (2006.01)
U.S. Cl. 438—458  [438/459; 438/514; 438/526; 438/530; 257/E21.568; 257/E21.57] 11 Claims
OG exemplary drawing
 
1. A method of fabricating an SOI wafer comprising:
an insulating film formation step of forming an insulating film on a first main surface of at least one of a first substrate, and a second substrate composed of silicon single crystal;
a separatory ion implanted layer formation step of forming a separatory ion implanted layer by implanting ions from an ion implantation surface on the first main surface side of the second substrate;
a bonding step of bonding the second substrate having the separatory ion implanted layer formed therein and the first substrate while opposing the first main surfaces with each other, and placing the insulating film in between;
a separation step of separating a bonded silicon single crystal film, later becoming an SOI layer, from the second substrate at a position of the separatory ion implanted layer, the separation step forming a separation surface of the bonded silicon single crystal film with a roughness (Rms) of 4.5 nm or less; and
a planarization step of planarizing having the separation surface side of the bonded silicon single crystal film so as to produce the SOI layer,
wherein the separatory ion implanted layer formation step further includes, based on a desired thickness of the SOI layer, adjusting a depth of formation of the separatory ion implanted layer measured from the ion implantation surface through control of a magnitude of an ion implantation energy, and
wherein a dose of the ion implantation is lowered as the depth of formation of the separatory ion implanted layer measured from the ion implantation surface becomes less, the dose of the ion implantation being such that the separation surface of the bonded silicon single crystal film formed in the separation step has the roughness (Rms) of 4.5 nm or less.