| US 7,601,635 B2 | ||
| Method of manufacturing a semiconductor device | ||
| Kentaro Yamada, Hitachi (Japan); Masato Takahashi, Mito (Japan); Tatsuyuki Konagaya, Hitachinaka (Japan); Takeshi Katoh, Hitachinaka (Japan); Masaki Sakashita, Mito (Japan); Koichiro Takei, Hitachinaka (Japan); Yasuhiro Obara, Hitachinaka (Japan); and Yoshio Fukayama, Ichinomiya (Japan) | ||
| Assigned to Renesas Technology Corp., Tokyo (Japan) | ||
| Filed on Jul. 03, 2007, as Appl. No. 11/822,191. | ||
| Application 11/822191 is a continuation of application No. 10/923045, filed on Aug. 23, 2004, granted, now 7,256,125. | ||
| Claims priority of application No. 2003-299793 (JP), filed on Aug. 25, 2003. | ||
| Prior Publication US 2007/0259512 A1, Nov. 08, 2007 | ||
| Int. Cl. H01L 21/4763 (2006.01); H01L 21/336 (2006.01) | ||
| U.S. Cl. 438—638 [438/305; 438/649; 257/E21.2; 257/E21.13] | 16 Claims |
| 1. A manufacturing method of a semiconductor device having a nonvolatile memory cell, comprising the steps of:
(a) forming a first insulating film over a semiconductor substrate;
(b) forming a first polycrystalline silicon film over the first insulating film;
(c) forming a second insulating film over the first polycrystalline silicon film;
(d) forming a second polycrystalline silicon film over the second insulating film;
(e) forming an WxSiy film over the second polycrystalline silicon film;
(f) after the step (e), patterning the WxSiy film, the second polycrystalline silicon film, the second insulating film and the first polycrystalline silicon film; and
(g) after the step (f), performing heat treatment,
wherein the step (d) comprises steps of:
(d1) forming a second region of the second polycrystalline silicon film over the second insulating film; and
(d2) forming a first region of the second polycrystalline silicon film over the second region of the second polycrystalline
silicon film, an impurity concentration of the first region of the second polycrystalline silicon film being smaller than
that of the second region of the second polycrystalline silicon film,
wherein, in the step (e), the WxSiy film is formed so as to satisfy y/x≧2, and
wherein the WxSiy film formed in the step (e) has a resistivity of 1000 μΩcm or greater and has a resistivity of 400 μΩcm or less after the
heat treatment in the step (g).
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