`obvious under 35 U.S.C. § 103 over Cade in view of Petersen
`
`
`Prior Art Cited in this Chart:
`U.S. Patent No. 4,599,792 to Cade et al. (“Cade”)
`Kurt E. Petersen (Silicon as a Mechanical Material, Proceedings of the IEEE, Vol.
`70, No. 5 (May 1982) (“Petersen”)
`
`
`Claim Language
`Claim 10
`The method of claim 1,
`wherein the step of
`etching includes the step
`of contacting the
`etchable layer to a liquid
`etchant that attacks the
`etchable layer rapidly
`and the etch-stop layer
`slowly.
`
`Cade in view of Petersen
`
`“The etch-back of the seed substrate 80 is performed
`with hydrofluoric-nitric-acetic acid (HNA) in the
`proportions of 1:3:8. The etchant HNA is an isotropic
`etch and attacks heavily doped p+ or n+ silicon.
`However, it does not appreciably attack silicon doped
`below the level of 1018 /cm3. The etch stopping
`characteristics are improved by the p+ /n junction at the
`interface 82.” Cade, 7:31-37.
`
`“Table II gives a brief summary of the characteristics of
`a number of common wet silicon etches.” Petersen, at
`423.
`
`“Three etchant systems are of particular interest due to
`their versatility: ethylene diamine, pyrocatechol, and
`water (EDP) [22]; KOH and water [23]; and HF,
`HNO3, and acetic acid CH3OOH (HNA) [24]. [25].”
`Petersen, at 423.
`
`Table II of Petersen, at 424
`
`
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`
`
`1
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`Petitioner Samsung - SAM1021
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`
`Claim Language
`
`
`
`
`
`
`
`
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`Cade in view of Petersen
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`2