Method for Uncovering Underlying Alignment Patterns

Patent metadata

Field	Value
Publication number	US-2016013069-A1
Application number	US-201514795478-A
Country	US
Kind code	A1
Filing date	Jul 9, 2015
Priority date	Jul 10, 2014
Publication date	Jan 14, 2016
Grant date	—

Abstract

Techniques disclosed herein include methods and systems for clearing out films or materials that may be covering alignment marks on substrates such as semiconductor wafers. Such films include photoresist layers, polymer films, thin films, and other layers that may be opaque or semi-opaque to optical alignment systems. A solvent composition is printed directly on resist films or other patterning films at specified points or regions on a substrate. The solvent composition printed or deposited on a resist film then begins to dissolve portions of the resist film that are directly underneath the solvent composition. The solvent composition and dissolved film material is then removed or washed from the substrate without causing other portions of the resist film to be dissolved, thereby uncovering alignment patterns or marks.

First claim

1 . A method for uncovering alignment marks, the method comprising:
receiving a substrate having one or more alignment marks that are visibly covered by an overlying layer, the overlying layer being soluble to a predetermined solvent; positioning the substrate on a substrate holder of a printing system; identifying planar locations on the substrate having alignment marks covered by the overlying film; depositing a solvent composition on the overlying layer at the identified planar locations using the printing system, the solvent composition including the predetermined solvent, the printing system configured to deposit solvent compositions based on a print pattern; and removing portions of the overlying layer having been dissolved by the predetermined solvent.

2 . The method of claim 1 , further comprising etching exposed portions of the underlying layer covering the one or more alignment marks.

3 . The method of claim 1 , wherein the overlying layer is a polymer film.

4 . The method of claim 1 , wherein depositing the solvent composition includes depositing a predetermined concentration of the predetermined solvent, wherein the predetermined concentration is selected to require a predetermined contact time to dissolve the overlying layer based on a given thickness of the overlying layer.

5 . The method of claim 1 , wherein the printing system is configured to deposit the solvent composition at a point resolution of less than 200 microns.

6 . The method of claim 5 , wherein the printing system is configured to deposit the solvent composition at a point resolution of less than 20 microns.

7 . The method of claim 1 , wherein removing portions of the overlying layer having been dissolved includes cleaning the substrate by executing a rinse step.

8 . A method for uncovering alignment marks, the method comprising:
receiving a substrate having one or more alignment marks that are visibly covered by an intermediate layer, the substrate having a patterning layer positioned on the intermediate layer, the patterning layer being soluble to a predetermined solvent; positioning the substrate on a substrate holder of a printing system; identifying planar locations on the substrate having alignment marks covered by the intermediate layer and the patterning layer; depositing a solvent composition on the patterning layer at the identified planar locations using the printing system, the solvent composition including the predetermined solvent, the printing system configured to deposit solvent compositions on substrates; and removing portions of the patterning layer having been dissolved by the predetermined solvent.

9 . The method of claim 8 , further comprising:
executing an etch step that etches the intermediate layer using the patterning layer as an etch mask such that material from the intermediate layer above the alignment marks is removed and alignment marks are visible.

10 . The method of claim 8 , wherein identifying planar locations on the substrate having alignment marks covered by the overlying film includes executing an optical pre-alignment process.

11 . The method of claim 8 , wherein identifying planar locations on the substrate having alignment marks covered by the overlying film includes executing a mechanical alignment process.

12 . The method of claim 8 , wherein identifying planar locations on the substrate having alignment marks covered by the overlying film includes executing a spot sensor alignment process.

13 . The method of claim 8 , wherein the intermediate layer is at least partially opaque, and wherein the patterning layer is a polymer film deposited by spin coating.

14 . The method of claim 8 , wherein the patterning layer is a photoresist film, and wherein depositing the solvent composition includes depositing a predetermined concentration of the predetermined solvent, the predetermined solvent dissolves the photoresist film at print locations, wherein the predetermined concentration is selected to require a predetermined contact time to dissolve the patterning layer based on a given thickness of the patterning layer.

15 . The method of claim 8 , wherein the printing system is configured to deposit the solvent composition at a point resolution of less than 200 microns.

16 . The method of claim 8 , wherein the printing system is configured to deposit the solvent composition at a point resolution of less than 20 microns.

17 . The method of claim 8 , wherein removing portions of the overlying layer having been dissolved includes cleaning the substrate using a de-ionized water rinse step.

18 . The method of claim 8 , wherein removing portions of the overlying layer having been dissolved includes removing the solvent composition from the substrate in less than approximately one second.

19 . The method of claim 8 , wherein removing portions of the overlying layer having been dissolved includes removing the solvent composition from the substrate in less than a contact time required to dissolve a given thickness of the patterning layer.

20 . The method of claim 8 , wherein the substrate includes semiconductor structures that have been at least partially fabricated.

Assignees

• Tokyo Electron Ltd

Inventors

• Devilliers Anton J

Classifications

• H10W46/503

  Located in scribe lines · CPC title

• H10W46/301

  for alignment · CPC title

• H10W46/00

  Marks applied to devices, e.g. for alignment or identification · CPC title

• H10P50/287 Primary

  by chemical means · CPC title

• H01L21/31133 Primary

  Electricity · mapped topic