Mask and method to pattern chromeless phase lithography contact hole
First Claim
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1. A method for projecting patterns onto a semiconductor substrate comprising:
- providing an illumination source;
providing a phase shift mask that has a first phase shift region and a second phase shift region, the first shift region is disposed on a first layer of the mask and the second phase shift region on a second layer of the mask, wherein the first and second phase shift regions are out of phase, the first phase shift region comprises a continuous unit cell, wherein the unit cell comprises a center section and extension sections, the extension sections are contiguous to and extend outwards from the center section, the distinct extension sections having a same width as the center section, the second phase shift region is adjacent to the unit cell in the first phase shift region; and
projecting light from the illumination source through the phase shift mask onto the semiconductor substrate, wherein destructive interference between the first and second phase shift regions due to shape of the unit cell creates a desired exposure pattern on a photosensitive layer on the substrate corresponding to about the center section.
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Abstract
A chromeless phase shift mask and Method for making and using. The A chromeless phase shift mask is used to pattern contact holes. The chromeless phase shift mask preferably comprises: a first phase shift region and a second phase shift region; the first region is comprised of a unit cell which is comprised of a rectangular center section and at least three rectangular sections (legs) outwards extending from the rectangular center section. The second region is adjacent to said first region. The interference between the first and second phase shift regions creates a contact hole pattern.
15 Citations
36 Claims
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1. A method for projecting patterns onto a semiconductor substrate comprising:
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providing an illumination source; providing a phase shift mask that has a first phase shift region and a second phase shift region, the first shift region is disposed on a first layer of the mask and the second phase shift region on a second layer of the mask, wherein the first and second phase shift regions are out of phase, the first phase shift region comprises a continuous unit cell, wherein the unit cell comprises a center section and extension sections, the extension sections are contiguous to and extend outwards from the center section, the distinct extension sections having a same width as the center section, the second phase shift region is adjacent to the unit cell in the first phase shift region; and projecting light from the illumination source through the phase shift mask onto the semiconductor substrate, wherein destructive interference between the first and second phase shift regions due to shape of the unit cell creates a desired exposure pattern on a photosensitive layer on the substrate corresponding to about the center section. - View Dependent Claims (2, 34)
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3. A method for projecting patterns onto a semiconductor substrate comprising:
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providing an illumination source; providing a phase shift mask that has a first phase shift region and a second phase shift region, wherein the first phase shift region is disposed on a first layer of the mask and the second phase shift region is disposed on a second layer, the first and second phase shift regions are out of phase, the first phase shift region including a continuous unit cell comprising a center section and distinct extension sections, the extension sections are contiguous to and extend outwards from the center section, the distinct extension sections having a same width as the center section, the center section having a rectangular shape, wherein the unit cell has a shape that when light passes through the mask, destructive interference between the first phase shift region and the second phase shift region creates a desired exposure pattern corresponding to about the center section; providing a lens system that receives the desired exposure pattern that is projected from the phase shift mask; reducing the desired exposure pattern in the lens system; and projecting the reduced desired exposure pattern onto a photosensitive layer on the semiconductor substrate. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 35)
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15. A method of forming a semiconductor device comprising:
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providing a substrate; and patterning the substrate comprising providing a mask with first and second phase shift regions which are out of phase, the first phase shift region comprising a continuous unit cell, wherein the unit cell is disposed in the first phase shift region and comprises a central portion and distinct extension portions which are contiguous to and extend from the central portion, the distinct extension sections having a same width as the central portion, and exposing the substrate with an illumination source using the mask, wherein destructive interference between the first and second phase shift regions due to shape of the unit cell produces a desired exposure pattern on the substrate. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 36)
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Specification