Methods of forming electronic devices using pitch reduction
View Patent ↗Embodiments of a method for device fabrication by reverse pitch reduction flow include forming a first pattern of features above a substrate and forming a second pattern of pitch-multiplied spacers subsequent to forming the first pattern of features. In embodiments of the invention the first pattern of features may be formed by photolithography and the second pattern of pitch-multiplied spacers may be formed by pitch multiplication. Other methods for device fabrication are provided.
1. A method of forming an electronic device, comprising:
forming a first pattern of features adjacent to one or more materials;
forming a photoresist material over the first pattern of features;
forming a second pattern of features through the photoresist material and laterally adjacent to the first pattern of features by removing portions of the photoresist material overlying the first pattern of features, the features of the second pattern having a lateral dimension relatively less than a lateral dimension of the features of the first pattern; and
using a combined pattern of the first pattern of features and the second pattern of features to transfer the first pattern of features and the second pattern of features to the one or more materials.
2. The method of claim 1 , further comprising:
forming a hard mask over the one or more materials prior to forming the first pattern of features; and
removing portions of the hard mask exposed through the combined pattern to transfer the first pattern of features and the second pattern of features to the one or more materials.
3. The method of claim 1 , further comprising forming a protective mask over portions of the first pattern of features and the second pattern of features, wherein the photoresist material is substantially removed prior to forming the protective mask.
4. The method of claim 1 , wherein forming the second pattern of features comprises:
patterning the photoresist material to form lithographic features;
removing additional portions of the photoresist material along opposing side surfaces of the lithographic features; and
conformally forming a spacer material adjacent to remaining portions of the photoresist material.
5. The method of claim 1 , wherein the combined pattern of the first pattern of features and the second pattern of features directly corresponds to positions of subsequently formed gate structures and conductive lines in the one or more materials.
6. The method of claim 5 , wherein the conductive lines are centrally located within an array and the gate structures are laterally adjacent to the conductive lines within a periphery of the array.
7. The method of claim 1 , further comprising forming openings in the one or more materials in a single material removal act using the combined pattern of the first pattern of features and the second pattern of features.
8. A method of forming an electronic device, comprising:
forming a first pattern of features in a peripheral region laterally adjacent to a central region;
forming a photoresist material over the first pattern of features;
forming a second pattern of features through the photoresist material in the central region;
forming a mask material over the first pattern of features and the second pattern of features; and
transferring the first pattern of features and the second pattern of features to one or more underlying materials to form conductive lines within the central region and periphery electrical structures within the peripheral region.
9. The method of claim 8 , further comprising forming the second pattern of features after forming the first pattern of features, the features of the second pattern including segmented portions of the photoresist material.
10. The method of claim 8 , wherein forming the second pattern of features comprises using spacers formed by pitch multiplication.
11. The method of claim 8 , wherein forming the second pattern of features comprises:
forming a conformal material adjacent to the photoresist material and the first pattern of features, a material composition of the conformal material differing from a material composition of the photoresist material;
selectively removing portions of the conformal material; and
substantially removing the photoresist material prior to forming the mask material.
12. The method of claim 8 , wherein forming the mask material comprises centering the mask material over the first pattern of features and the second pattern of features while leaving end portions thereof exposed.
13. The method of claim 8 , wherein transferring the first pattern of features and the second pattern of features to the one or more underlying materials comprises forming a modified pattern of the features of the second pattern to be relatively smaller than the features of the first pattern.
14. The method of claim 8 , wherein forming the conductive lines comprises forming access lines, and wherein forming the periphery electrical structures comprises forming one or more of landing pads, transistors, and local interconnects.
15. A method of forming an electronic device, comprising:
forming a selectively definable material over at least a portion of a peripheral region including segmented portions of a mask material;
forming pitch-multiplied spacers using segmented portions of the selectively definable material within an array region, laterally adjacent and at least partially surrounded by the peripheral region; and
forming openings in a semiconductive material to form electrical structures within the peripheral region and conductive lines within the array region using the segmented portions of the mask material combined with the pitch-multiplied spacers.
16. The method of claim 15 , further comprising forming the mask material over the semiconductive material, and patterning the mask material to form the segmented portions of the mask material within the peripheral region prior to forming the selectively definable material.
17. The method of claim 15 , further comprising:
removing the segmented portions of the selectively definable material; and
forming a protective mask material over the pitch-multiplied spacers.
18. The method of claim 15 , wherein forming the pitch-multiplied spacers comprises enlarging initial openings between neighboring portions of the selectively definable material by laterally removing portions of the selectively definable material.
19. The method of claim 15 , wherein forming the pitch-multiplied spacers comprises conformally forming a spacer material over the segmented portions of the selectively definable material, and selectively removing portions of the spacer material to separate the pitch-multiplied spacers from one another.