Method for carrying out a double or multiple exposure
View Patent ↗The mutually associated structure patterns, which are provided on one mask, or a plurality of masks for a double or multiple exposure can be received by the mask substrate holder. The mask substrate holder has two receiving stations one for each of the masks. Alternatively, both structure patterns for the double exposure are formed on one mask. The substrate holder has one receiving station. The substrate holder, is displaced from the section including first structure pattern to the second, between the two exposure operations, without the masks having to be loaded or unloaded, and realigned.
1. A method for carrying out a double or multiple exposure of a resist for transferring at least two different structure patterns into one layer level arranged on a semiconductor wafer, comprising:
providing a mask structure including a first structure pattern and a second structure pattern;
loading one mask substrate holder of a wafer scanner, as the exposure apparatus with the mask structure, the substrate holder including an exposure slot;
aligning the one mask substrate holder such that, in a first position, the first structure pattern of the mask structure enters the beam path of projection optics in the exposure apparatus in order to determine a first set of alignment parameters;
aligning the one mask substrate holder, such that, in a second position, the second structure pattern of the mask structure enters the beam path of the projection optics in order to determine a second set of alignment parameters;
exposing a plurality of exposure fields on the semiconductor wafer, including, for each exposure field:
(a) moving the one mask substrate holder using the first set of alignment parameters into the first position;
(b) projecting the first structure pattern in a first scanning direction into the resist in order to expose a first exposure field on the semiconductor wafer;
(c) moving the one mask substrate holder using the second set of alignment parameters into the second position; and
(d) projecting the second structure pattern in a second scanning direction into the resist immediately after the projection of the first structure pattern into the resist in order to expose the first exposure field on the semiconductor wafer without the mask structure being unloaded from the mask substrate holder between the projection steps, wherein the first and second scanning directions are oriented substantially opposite to one another; and
unloading the mask structure.
2. The method of claim 1 , wherein the mask structure comprises a first mask including the first structure pattern and a second mask including the second structure pattern.
3. The method of claim 2 , wherein the one mask substrate holder includes a first receiving station that receives the first mask and a second receiving station that receives the second mask.
4. The method of claim 2 , wherein the first set of alignment parameters and the second set of alignment parameters include a total of sixteen parameters.
5. The method of claim 2 , wherein the exposing the plurality of exposure fields includes (a) to (d) being repeated in the reverse order following (d) in order to expose a second exposure field, which directly adjoins the first exposure field on the semiconductor wafer.
6. The method of claim 2 , wherein the exposing the plurality of exposure fields includes moving the one mask substrate holder into the first position in a first displacement direction and moving the one mask substrate holder into the second position in a second displacement direction, the first and second displacement directions being oriented substantially opposite to one another.
7. The method of claim 6 , wherein the first displacement direction and the second displacement direction are substantially perpendicular to the first scanning direction and to the second scanning direction.
8. The method of claim 6 , wherein the first displacement direction and the second displacement direction are substantially parallel to the first scanning direction and to the second scanning direction.
9. The method of claim 6 , wherein the exposing the plurality of exposure fields includes arranging an aperture opening such that regions outside the first structure pattern are covered prior to the projection of the first structure pattern into the resist.
10. The method of claim 1 , wherein the mask structure comprises a single mask with a first part that includes the first structure pattern and a second part that includes the second structure pattern.
11. The method of claim 10 , wherein the loading the one mask substrate holder includes the mask substrate holder having a receiving station for the single mask.
12. The method of claim 10 , wherein the first set of alignment parameters and the second set of alignment parameters include a total of twelve parameters.
13. The method of claim 10 , wherein the single mask includes an opaque web that is arranged between the first part including the first structure pattern and the second part including the second structure pattern.
14. The method of claim 13 , wherein the opaque web comprises a chrome web.