Double patterning by PTD and NTD process
A method of manufacturing using a double patterning method is provided. The double patterning method uses a first developer and a second developer that are different. For example, the first developer may be a positive tone developer for a positive photoresist while the second developer may be a negative tone developer for the positive photoresist. Photoresists having a photoactive compound are also provided that may be useful in double patterning methods. The resulting double patterning results, wherein a dimension of a variable first dense pattern is larger than a dimension of a variable second dense pattern.
1. A method of making a photoresist pattern comprising:
providing a photoresist layer;
exposing the photoresist layer to a first light passing through a first mask having a variable first line/space ratio;
developing the photoresist layer using a positive tone developer (PTD);
exposing the photoresist layer to a second light passing through a second mask having a variable second line/space ratio, wherein an approximately opaque region of the second mask is positioned substantially at the center of an approximately transparent region of the first mask; and
developing the photoresist layer using a negative tone developer (NTD);
wherein the variable first line/space ratio is larger than the variable second line/space ratio.
2. The method of claim 1 , wherein the photoresist layer comprises a positive photoresist.
3. The method of claim 1 , wherein the variable first line/space ratio is from about 1 to about 9.
4. The method of claim 1 , wherein the variable second line/space ratio is from about 1/9 to about 1.
5. A method of making a photoresist pattern comprising:
exposing a photoresist with a first mask having a variable first dense pattern and a periphery pattern;
developing the photoresist with a positive tone developer (PTD);
exposing the photoresist with a second mask having a variable second dense pattern, wherein an opaque region of the second mask is positioned substantially at the center of an transparent region of the first mask; and
developing the photoresist with a negative tone developer (NTD).
6. The method of claim 5 , wherein the photoresist comprises a positive photoresist.
7. The method of claim 5 , wherein a dimension of the variable first dense pattern is larger than a dimension of the variable second dense pattern.
8. The method of claim 5 , wherein:
the first mask comprising a first opaque region and a first substantially translucent region surrounding the first opaque region.
9. The method of claim 8 , wherein the first opaque region defines a corresponding pad and the opaque region of the second mask defines a separation region to divide the corresponding pad into at least two portions.