Process for making a semiconductor MOS transistor
First Claim
1. A process for forming a MOS transistor having an LDD structure with at least a first impurity region and a second impurity region formed in a semiconductor substrate and a gate electrode of a first width, wherein the first impurity region has a higher inpurity concentration than the second impurity region and is spaced apart from a side of the gate electrode, the process comprising the steps of:
- (a) forming an insulating layer on the semiconductor substrate;
(b) forming a conductive layer having a thickness on the insulating layer;
(c) forming an etch inhibition pattern on the conductive layer, wherein the etch inhibition pattern has a width greater than the first width;
(d) carrying out an anisotropic etching on the conductive layer using the etch inhibition pattern as a mask to remove a portion of the thickness of the conductive layer;
(e) carrying out an isotropic etching on the anisotropically etched conductive layer to form a gate electrode pattern, wherein the gate electrode pattern has concave sides and an upper portion of a second width greater than the first width;
(f) carrying out a first ion implantation for forming the first inpurity region in the semiconductor substrate, wherein the etch inhibition pattern and the gate electrode pattern having the upper portion of the second width are used as a first mask;
(g) removing the etch inhibition pattern after the first ion implantation;
(h) oxidizing e gate electrode pattern to form an oxide layer on the gate electrode pattern;
(i) removing the oxide layer for forming the gate electrode of the first width;
(j) carrying out a second ion implantation for forming the second impurity region in the semiconductor substrate, wherein the gate electrode is used as a second mask; and
(k) carrying out a heat treatment, wherein the LDD structure is formed.
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Abstract
The present invention provides a process for forming an MOS semiconductor device having an LDD structure, which includes a forming a gate electrode by first etching a conductive layer to a certain depth by an RIE process and by second etching the conductive layer by an isotropic plasma etching process. In forming the source/drain of the device, an n+ source/drain and an n- source/drain are formed in a sequential manner. The gate line first is formed with its width over-sized compared with its channel length, and finally is formed to its final size.
16 Citations
19 Claims
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1. A process for forming a MOS transistor having an LDD structure with at least a first impurity region and a second impurity region formed in a semiconductor substrate and a gate electrode of a first width, wherein the first impurity region has a higher inpurity concentration than the second impurity region and is spaced apart from a side of the gate electrode, the process comprising the steps of:
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(a) forming an insulating layer on the semiconductor substrate; (b) forming a conductive layer having a thickness on the insulating layer; (c) forming an etch inhibition pattern on the conductive layer, wherein the etch inhibition pattern has a width greater than the first width; (d) carrying out an anisotropic etching on the conductive layer using the etch inhibition pattern as a mask to remove a portion of the thickness of the conductive layer; (e) carrying out an isotropic etching on the anisotropically etched conductive layer to form a gate electrode pattern, wherein the gate electrode pattern has concave sides and an upper portion of a second width greater than the first width; (f) carrying out a first ion implantation for forming the first inpurity region in the semiconductor substrate, wherein the etch inhibition pattern and the gate electrode pattern having the upper portion of the second width are used as a first mask; (g) removing the etch inhibition pattern after the first ion implantation; (h) oxidizing e gate electrode pattern to form an oxide layer on the gate electrode pattern; (i) removing the oxide layer for forming the gate electrode of the first width; (j) carrying out a second ion implantation for forming the second impurity region in the semiconductor substrate, wherein the gate electrode is used as a second mask; and (k) carrying out a heat treatment, wherein the LDD structure is formed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A process for forming a transistor having an LDD structure with at least a first impurity region and a second impurity region formed in a semiconductor substrate and a gate electrode of a first width, wherein the first impurity region has a higher impurity concentration than the second impurity region and is spaced apart from a side of the gate electrode, the process comprising the steps of:
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(a) forming a first insulating layer on the semiconductor substrate; (b) forming a conductive layer having a thickness on the first insulating layer; (c) forming an etch inhibition pattern on the conductive layer, wherein the etch inhibition pattern has a width greater than the first width; (d) carrying out a first anisotropic etching on the conductive layer to remove a portion of the thickness of the conductive layer using the etch inhibition pattern as a mask; (e) carrying out an isotropic etching on the anisotropically etched conductive layer to form a gate electrode pattern using the etch inhibition pattern as a mask, wherein the gate electrode pattern has concave sides and an upper portion including a tip portion, the upper portion having a second width greater than the first width; (f) carrying out a first ion implantation in the semiconductor substrate for forming the first impurity region using the etch inhibition pattern and the gate electrode pattern as a first mask; (g) removing the etch inhibition pattern after the first ion implantation; (h) carrying out a second anisotropic etching on the gate electrode pattern for forming a gate electrode of the first width, wherein the tip portion of the gate electrode pattern is etched by the second anisotropic etching; (i) carrying out a second ion implantation in the semiconductor substrate for forming the second impurity region using the gate electrode as a second mask; (j) forming a second insulating layer on the first insulating layer and the gate electrode; and (k) carrying out a heat treatment for forming the LDD structure. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification