IP Library › Granted Patent US 12,663,722
Granted Patent B2
US 12,663,722 · App. 17/926,108 · Granted Jun 23, 2026

System and method to control defects in projection-based sub-micrometer additive manufacturing

Inventor: Sourabh Kumar Saha (Atlanta, GA)
Assignee: Georgia Tech Research Corporation
G03F7/2055G03F7/70
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Quick Facts
Patent No.
US 12,663,722
App. No.
17/926,108
Filed
Nov 17, 2022
Granted
Jun 23, 2026
Kind
B2
Art Unit
2899
USPC
430/326
Abstract

An exemplary optical projection method and system is disclosed, e.g., femtosecond projection two-photon lithography (FP-TPL) based operation, that applies multiple temporally focused light with reduced density of the projected mask to control over-polymerization defects (e.g., without need to tune the photopolymer composition) when certain aspect ratio of the submicron features are desired.

Claims (53)

1 . A method for performing an additive manufacturing operation to form a structure by processing a photopolymer resist material, the method comprising:

generating a first temporally focused light sheet onto or within a first region of a photopolymer resist material for a first finite duration of time to cause a first simultaneous polymerization of a first set of selected portions of the photopolymer resist material corresponding to a first selected pattern; and

generating a second temporally focused light sheet onto or within a second region of a photopolymer resist material for a second finite duration of time to cause a second simultaneous polymerization of a second set of selected portions of the photopolymer resist material corresponding to a second selected pattern,

wherein the first temporally focused light sheet and the second temporally focused light sheet collectively illuminate a continuous region on or in the photopolymer resist material in a depth direction of the photopolymer resist material that includes the first region and the second region, and

wherein each of the first temporally focused light sheet and the second temporally focused light sheet is generated by directing a respective laser beam to a tunable mask and actuating a plurality of optically dispersive elements of the tunable mask to split the respective laser beam into distinct beam components to be collimated and focused to the first region and the second region, respectively.

2 . The method of claim 1 , wherein the photopolymer resist material illuminated by the first temporally focused light sheet and the second temporally focused light sheet has suppressed occurrences of over-polymerization.

3 . The method of claim 1 , wherein the photopolymer resist material illuminated by the first temporally focused light sheet and the second temporally focused light sheet, when processed, provides a top surface for a 3D structure that is observable to be flat and uniform.

4 . The method of claim 1 , further comprising:

simulating the generating first temporally focused light sheet and the generated second temporally focused light sheet.

5 . The method of claim 1 , wherein the photopolymer resist material illuminated by the first temporally focused light sheet and the second temporally focused light sheet can produce a submicron structural feature having an aspect ratio between about 1.2 and 2.0.

6 . The method of claim 1 , further comprising:

receiving, by a processor, a first image having a plurality of pixels corresponding to the first selected pattern;

directing, by the processor, the generation of the laser beam; and

directing, by the processor, based on the first image, the tunable mask to generate the first temporally focused light sheet according to the first selected pattern.

7 . The method of claim 1 , further comprising:

receiving, by a processor, a second image having a plurality of pixels corresponding to the second selected pattern;

directing, by the processor, the generation of the laser beam; and

directing, by the processor, based on the second image, the tunable mask to generate the second temporally focused light sheet according to the second selected pattern.

8 . The method of claim 1 , wherein the first finite duration of time is the same as the second finite duration of time.

9 . The method of claim 1 , wherein the first finite duration of time is different from the second finite duration of time.

10 . The method of claim 1 , wherein the first temporally focused light sheet has an associated first intensity level, wherein the second temporally focused light sheet has an associated second intensity level, and wherein the first intensity level is same as the second intensity level.

11 . The method of claim 1 , wherein the first temporally focused light sheet has an associated first intensity level, wherein the second temporally focused light sheet has an associated second intensity level, and wherein the first intensity level is different from the second intensity level.

12 . The method of claim 1 , wherein the second temporally focused light sheet is applied immediately after the first temporally focused light sheet or before a sufficient time has passed for localized effects of polymerization mechanisms of the photopolymer resist material to be minimized.

13 . A laser-based manufacturing system for fabricating non-planar three-dimensional layers, the system comprising:

a laser for producing a laser beam with a plurality of optical wavelengths;

a tunable mask comprising a plurality of optically dispersive elements, each optically dispersive element being configured to receive the laser beam and split the beam into a plurality of distinct beam components, wherein each said beam component has spatially separated optical spectral components;

an optical assembly configured to collimate the distinct beam components to create a collimated beam and to focus the collimated beam into a focused laser beam, which is projected at an image plane onto or within a photopolymer resist material; and

a controller operatively coupled to the tunable mask, the controller being configured by instructions to:

direct the tunable mask to actuate a first set of plurality of optically dispersive elements to direct the tunable mask to receive a laser beam and split the beam into distinct beam components to be collimated and focused by the optical assembly to generate a first temporally focused light sheet onto or within a first region of the photopolymer resist material, wherein the first temporally focused light sheet is generated onto or within the first region for a first finite duration of time to cause a first simultaneous polymerization of a first set of selected portions of the photopolymer resist material corresponding to a first selected pattern; and

direct the tunable mask to actuate a second set of plurality of optically dispersive elements to direct the tunable mask to receive the laser beam and split the beam into distinct beam components to be collimated and focused by the optical assembly to generate a second temporally focused light sheet onto or within a first region of a photopolymer resist material, wherein the second temporally focused light sheet is generated onto or within the first region for a second finite duration of time to cause a second simultaneous polymerization of a first set of selected portions of the photopolymer resist material corresponding to a first selected pattern,

wherein the first temporally focused light sheet and the second temporally focused light sheet collectively illuminate a continuous region on or in the photopolymer resist material in a depth direction of the photopolymer resist material that includes the first region and the second region.

14 . The laser-based manufacturing system of claim 13 , further comprising:

a support stage having a surface to support the photopolymer resist material; and

one or more actuators configured to move a focusing element relative to the stage to write out a layer of the photopolymer resist material.

15 . The laser-based manufacturing system of claim 13 , wherein the tunable mask comprises micromirrors.

16 . A non-transitory computer readable medium having instructions stored thereon, wherein execution of the instructions by a processor causes the processor to:

receive a first image having a plurality of pixels corresponding to a first pattern to project on and into a photopolymer resist material in an additive manufacturing operation to form a first layer of a structure;

receive a second image having a plurality of pixels corresponding to a second pattern to project on and into the photopolymer resist material in the additive manufacturing operation to form the first layer of the structure;

direct, based on the first image, a tunable mask to generate a first temporally focused light sheet according to the first pattern; and

direct, based on the second image, the tunable mask to generate a second temporally focused light sheet according to the second pattern,

wherein the first temporally focused light sheet is generated onto or within a first region of the photopolymer resist material for a first finite duration of time to cause a first simultaneous polymerization of a first set of selected portions of the photopolymer resist material corresponding to the first pattern,

wherein the second temporally focused light sheet is generated onto or within a second region of a photopolymer resist material for a second finite duration of time to cause a second simultaneous polymerization of a second set of selected portions of the photopolymer resist material corresponding to the second pattern,

wherein the first temporally focused light sheet and the second temporally focused light sheet are collectively illuminated on or into a continuous region in the photopolymer resist material in a depth direction of the photopolymer resist material that includes the first region and the second region, and

wherein each of the first temporally focused light sheet and the second temporally focused light sheet is generated by directing a respective laser beam to a tunable mask and actuating a plurality of optically dispersive elements of the tunable mask to split the respective laser beam into distinct beam components to be collimated and focused to the first region and the second region, respectively.

17 . The non-transitory computer readable medium of claim 16 , wherein the execution of the instructions by the processor further causes the processor to:

receive a third image having a plurality of pixels corresponding to a third pattern to project on and into a second photopolymer resist material in the additive manufacturing operation to form a second layer of the structure;

receive a fourth image having a plurality of pixels corresponding to a fourth pattern to project on and into the second photopolymer resist material in the additive manufacturing operation to form the second layer of the structure;

direct, based on the third image, the tunable mask to generate a third temporally focused light sheet according the third pattern; and

direct, based on the second image, the tunable mask to generate a fourth temporally focused light sheet according the fourth pattern,

wherein the third temporally focused light sheet is generated onto or within a third region of the second photopolymer resist material for a third finite duration of time to cause a third simultaneous polymerization of a third set of selected portions of the second photopolymer resist material corresponding to the third pattern,

wherein the fourth temporally focused light sheet is generated onto or within a fourth region of a photopolymer resist material for a second finite duration of time to cause a fourth simultaneous polymerization of a fourth set of selected portions of the second photopolymer resist material corresponding to the fourth pattern, and

wherein the third temporally focused light sheet and the fourth temporally focused light sheet are collectively illuminated on or into a continuous region in the second photopolymer resist material that includes the third region and the fourth region.

18 . The non-transitory computer readable medium of claim 16 , wherein the photopolymer resist material illuminated by the first temporally focused light sheet and the second temporally focused light sheet has suppressed occurrences of over-polymerization to provide a top surface for the first layer of the structures that is observable to be flat and uniform.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 7, 2023
From: SAHA, SOURABH KUMAR
To: GEORGIA TECH RESEARCH CORPORATION
Reel/Frame 063257/0834 →
Continuity (2)
Provisional Application 63027606 · May 20, 2020
Related Publication 20230194992A1 · Jun 22, 2023
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