US5244759A — Single-alignment-level lithographic technique for…

Claim 1

Independent Claim 284 words

A lithographic technique for making a phase-shifting mask including the steps of: (a) introducing into first, second, and third regions of a resist layer mutually differing first, second, and third doses of resist-modifying radiation per unit area, respectively, the resist layer being located upon a first material layer which is located upon a second material layer, the first region being contiguous with and having a first common boundary with the second region, and the second region being contiguous with and having a second common boundary with the first region, the first material layer being optically absorbing and the second material layer being transparent with respect to prescribed optical radiation; (b) subjecting the resist layer to a first development procedure, whereby the first region, but not the second or third regions, of the resist layer is dissolved; (c) etching the first material layer, but not the second material layer, solely in a region thereof underlying the original first region of the resist layer; (d) subjecting the resist layer to a second development procedure, whereby the second but not the third region of the resist layer is dissolved; (e) etching a thickness of the second material layer solely in a region underlying the original first region of the resist layer, whereby the thickness of the second material layer is reduced thereat; and (f) etching the first material layer in a region thereof underlying the original second region of the resist layer, wherein the order of sequence of the steps is (a), (b), (c), (d), (e), (f), whereby there are created an edge in the first material layer and an edge in the second material layer that are aligned with the second and first common boundaries, respectively.

Claim 2

Dependent Claim 284 words

A lithographic technique for making a phase-shifting mask including the steps of: (a) introducing into first, second, and third regions of a resist layer mutually differing first, second, and third doses of resist-modifying radiation per unit area, respectively, the resist layer being located upon a first material layer which is located upon a second material layer, the first region being contiguous with and having a first common boundary with the second region, and the second region being contiguous with and having a second common boundary with the first region, the first material layer being optically absorbing and the second material layer being transparent with respect to prescribed optical radiation; (b) subjecting the resist layer to a first development procedure, whereby the first region, but not the second or third regions, of the resist layer is dissolved; (c) etching the first material layer, but not the second material layer, solely in a region thereof underlying the original first region of the resist layer; (d) subjecting the resist layer to a second development procedure, whereby the second but not the third region of the resist layer is dissolved; (e) etching a thickness of the second material layer solely in a region underlying the original first region of the resist layer, whereby the thickness of the second material layer is reduced thereat; and (f) etching the first material layer in a region thereof underlying the original second region of the resist layer, wherein the order of sequence of the steps is (a), (b), (c), (d), (e), (f), whereby there are created an edge in the first material layer and an edge in the second material layer that are aligned with the second and first common boundaries, respectively.

Claim 3

Dependent Claim 34 words

The technique of claim 1 in which the third dose is essentially zero, the resist is a positive tone resist, and the first dose of radiation per unit area is greater than the second.

Claim 4

Dependent Claim 12 words

The technique of claim 2 in which the radiation is essentially electrons.

Claim 5

Dependent Claim 16 words

The techniques of claim 3 in which the etching recited in step (e) is dry etching.

Claim 6

Dependent Claim 16 words

The technique of claim 2 in which the etching recited in step (e) is dry etching.

Claim 7

Dependent Claim 34 words

The technique of claim 1 in which the first dose is essentially zero, the resist is a negative tone resist, and the third dose of radiation per unit area is greater than the second.

Claim 8

Dependent Claim 12 words

The technique of claim 4 in which the radiation is essentially electrons.

Claim 9

Dependent Claim 46 words

The technique of claim 1 in which the second material layer is located on a substrate composed of a third material, and in which the entire thickness of the second material layer underlying the original first region of the resist layer is removed during step (e).

Claim 10

Dependent Claim 121 words

A photolithographic method including the steps of: (a) forming a phase-shifting mask in accordance with the steps recited in claim 1; (b) directing the prescribed optical radiation onto and through the mask, and focusing the optical radiation propagating through the mask onto a photoresist layer located on a major surface of a wafer, or located on a layer of material located on a major surface of a wafer, in which the device is to be fabricated; (c) developing the photoresist, whereby a patterned photoresist layer is formed having an edge feature therein; and (d) defining a feature at the major surface of the wafer or in the layer of material, in accordance with the edge feature of the patterned photoresist layer.

Claim 11

Dependent Claim 144 words

A photolithographic method including the steps of: (a) forming a phase-shifting mask in accordance with the steps recited in claim 1, in which the third dose is substantially zero, the resist is a positive tone resist, and the first dose of the resist-modifying radiation per unit area is greater than the second; (b) directing the prescribed optical radiation onto and through the mask, and focusing the optical radiation propagating through the mask onto a photoresist layer located on a major surface of a wafer, or located on a layer of material located on a major surface of wafer; (c) developing the photoresist layer, whereby a patterned photoresist layer is formed having an edge feature therein; and (d) defining a feature at the major surface of the wafer or in the layer of material, in accordance with the edge feature of the patterned photoresist layer.

Claim 12

Dependent Claim 152 words

A photolithographic method including the steps of: (a) forming a phase-shifting mask in accordance with the steps recited in claim 1, in which the radiation is essentially electrons and in which the third dose is substantially zero, the resist is a positive tone resist, and the first dose of the resist-modifying radiation per unit area is greater than the second; (b) directing the prescribed optical radiation onto and through the mask, and focusing the optical radiation propagating through the mask onto a photoresist layer located on a major surface of a wafer, or located on a layer of material located on a major surface of wafer; (c) developing the photoresist layer, whereby a patterned photoresist layer is formed having an edge feature therein; and (d) defining a feature at the major surface of the wafer or in the layer of material, in accordance with the edge feature of the patterned photoresist layer.

Claim 13

Dependent Claim 132 words

A photolithographic method of fabricating a semiconductor integrated circuit device including the steps of: (a) forming a phase-shifting mask in accordance with the steps recited in claim 1; (b) directing the prescribed optical radiation onto and through the phase-shifting mask, and focusing the optical radiation propagating through the mask onto a photoresist layer located on a major surface of a semiconductor wafer, or located on a layer of material located on a major surface of a semiconductor wafer, in which the device is to be fabricated; (c) developing the photoresist layer, whereby a patterned photoresist layer is formed having an edge feature therein; and (d) defining a feature at the major surface of the wafer or in the layer of material, in accordance with the edge feature of the patterned photoresist layer.

Claim 14

Dependent Claim 165 words

A photolithographic method of fabricating a semiconductor integrated circuit device including the steps of: (a) forming a phase-shifting mask in accordance with the steps recited in claim 1, in which the third dose is substantially zero, the resist is a positive tone resist, and the first dose of the resist-modifying radiation per unit area is greater than the second; (b) directing the prescribed optical radiation onto and through the mask, and focusing the optical radiation propagating through the mask onto a photoresist layer located on a major surface of a semiconductor wafer, or located on a layer of material located on a major surface of a semiconductor wafer, in which the semiconductor integrated circuit device is to be fabricated; (c) developing the photoresist layer, whereby a patterned photoresist layer is formed having an edge feature therein; and (d) defining a feature at the major surface of the wafer or in the layer of material, in accordance with the edge feature of the patterned photoresist layer.

Claim 15

Dependent Claim 172 words

A photolithographic method of fabricating a semiconductor integrated circuit including the steps of: (a) forming a phase-shifting mask in accordance with the steps recited in claim 1, in which the radiation is essentially electrons and in which the third dose is substantially zero, the resist is a positive tone resist, and the first dose of the resist-modifying radiation per unit area is greater than the second; (b) directing the prescribed optical radiation onto and through the mask, and focusing the optical radiation propagating through the mask onto a photoresist layer located on a major surface of a semiconductor wafer, or located on a layer of material located on a major surface of a semiconductor wafer, in which the semiconductor integrated circuit device is to be fabricated; (c) developing the photoresist layer, whereby a patterned photoresist layer is formed having an edge feature therein; and (d) defining a feature at the major surface of the wafer or in the layer of material, in accordance with the edge feature of the patterned photoresist layer.

Claim 16

Dependent Claim 164 words

A photolithographic method of fabricating a semiconductor integrated circuit device including the steps of: (a) forming a phase-shifting mask in accordance with the steps recited in claim 1, in which the first dose is substantially zero, the resist is a negative tone resist, and the third dose of the resist-modifying radiation per unit area is greater than the second; (b) directing the prescribed optical radiation onto and through the mask, and focusing the optical radiation propagating through the mask onto a photoresist layer located on a major surface of a semiconductor wafer, or located on a layer of material located on a major surface of a semiconductor wafer, in which the semiconductor integrated circuit is to be fabricated; (c) developing the photoresist layer, whereby a patterned photoresist layer is formed having an edge feature therein; and (d) defining a feature at the major surface of the wafer or in the layer of material, in accordance with the edge feature of the patterned photoresist layer.

Claim 17

Dependent Claim 173 words

A photolithographic method of fabricating a semiconductor integrated device including the steps of: (a) forming a phase-shifting lithographic mask in accordance with the steps recited in claim 1, in which the radiation is essentially electrons and in which the first dose is substantially zero, the resist is a negative tone resist, and the third dose of the resist-modifying radiation per unit area is greater than the second; (b) directing the prescribed optical radiation onto and through the mask, and focusing the optical radiation propagating through the mask onto a photoresist layer located on a major surface of a semiconductor wafer, or located on a layer of material located on a major surface of a semiconductor wafer, in which the semiconductor integrated circuit device is to be fabricated; (c) developing the photoresist layer, whereby a patterned photoresist layer is formed having an edge feature therein; and (d) defining a feature at the major surface of the wafer or in the layer of material, in accordance with the edge feature of the patterned photoresist layer.

Claim 18

Dependent Claim 16 words

The technique of claim 1 in which the etching recited in step (e) is dry etching.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1996-09-13	1997-03-15	1997-09-14	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2000-09-13	2001-03-15	2001-09-14	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2004-09-13	2005-03-15	2005-09-14	$7700.00	Window Closed / Lapsed

Single-alignment-level lithographic technique for achieving self-aligned features

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