EP0052227A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method for forming a self-aligned contact and a plasma especially applicable in performing said method
Assignee: International Business Machines Corp
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Filing: 1981-10-09
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Granted: —
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Expires: 2001-10-09
Abstract
Abstract The method is applied after the contact region (27a) has been covered by a silicon nitride oxidation blocking mask (28a) which subsequently was subjected to oxidation and/or doping processes causing the formation of various compounds in the silicon nitride (28a) and at the interface between the silicon nitride (28a) and the contact region (27a). A non-selective etching process is used to remove silicon nitride (28a) and the formed compounds. In particular it has been found that a plasma comprising a organo-halide and an excess of oxygen can be used to non-selectively etch the silicon dioxide, the silicon nitride, its associated compounds and the material of the contact region, like polysilicon. The method is useful e.g. for the formation of the polysilicon gate of a silicon field effect transistor.
Inventors
- 👤 Edward Donald Purcell
- 👤 Francis Roger White
- 👤 John Michael Wursthorn
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 10:15
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10P; H10P14/00; H10P14/60; H10P14/61; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10P76/00; H10P76/40; H10P95/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
69 words
Method for forming a self-aligned contact to a region of an integrated circuit to be produced said region previously having been protected by a silicon nitride oxidation blocking mask (28a), which subsequently has undergone an oxidation and/or doping process, characterized in that the silicon nitride blocking mask (28a) is removed with an etchant which is substantially none-selective with respect to silicon dioxide, silicon nitride and the oxidation products thereof.
Claim 2
Dependent Claim
69 words
Method for forming a self-aligned contact to a region of an integrated circuit to be produced said region previously having been protected by a silicon nitride oxidation blocking mask (28a), which subsequently has undergone an oxidation and/or doping process, characterized in that the silicon nitride blocking mask (28a) is removed with an etchant which is substantially none-selective with respect to silicon dioxide, silicon nitride and the oxidation products thereof.
Claim 3
Dependent Claim
20 words
' Method according to claim 1, wherein said etchant comprises uncharged reactive, compounds, atoms and radicals extracted from a plasma.
Claim 4
Dependent Claim
27 words
Method according to claim 1 or 2, wherein the selective removal of defined materials is ensured by adjusting the thicknesses of the materials exposed to the etchant.
Claim 5
Dependent Claim
88 words
Method according to any one of claims 1 to 3, wherein the part to be produced is placed in a plasma generating tool, an electrically floating screen (20) is placed around said part, a gas capable of forming reactive compounds, atoms and radicals in a glow discharge is introduced into said tool, outside of said screen in said tool a plasma is greated from said gas and said plasma is maintained for a period of time sufficient for particles from said plasma to remove said blocking mask (28a).
Claim 6
Dependent Claim
25 words
Method according to any one of claims 1 to 4, wherein the region to be contacted is the gate (27a) of a field effect transistor.
Claim 7
Dependent Claim
20 words
Method according to any one of claims 1 to 5, wherein the region to be contacted is made of polysilicon.
Claim 8
Dependent Claim
51 words
A plasma for etching silicon nitride and especially applicable in the method according to any one of claims 2 to 6, characterized in that the plasma is created from a gas mixture containing an organo-halide gas and oxygen with the oxygen content being at least equal to the organo-halide gas content.
Claim 9
Dependent Claim
23 words
Plasma according to claim 7, wherein the oxygen content in the gas mixture comprises at least 50 and less than 100% by volume.
Claim 10
Dependent Claim
16 words
Plasma according to claims 7 or 8, wherein in addition a substantially inert gas is contained.
Claim 11
Dependent Claim
20 words
Plasma according to claim 9, wherein the inert gas is selected from the group consisting of argon, nitrogen and xenon.
References Cited (Backward Citations)
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