# US 2013/0156293 A1 · Methods and Systems For Grain Size Evaluation Of Multi-Cystalline Solar Wafers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0156293 A1 - Document ID: US20130156293A1 - Status: Published application - Kind: A1 - Application number: 13/329,914 - Filed: 2011-12-19 - Published: 2013-06-20 - Earliest claimed: 2011-12-19 - Assignees: Memc Singapore Pte. Ltd. (Uen200614794D) - Inventors: Gang Shi; Thomas E. Doane; Steven L. Kimbel; Robert H. Fuerhoff - Web page: https://patentgrep.com/patent/US20130156293A1 ## CPC - H10P 74/203: {Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects} - G01N 21/8806: {Specially adapted optical and illumination features} - G01N 21/9501: {Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20)} - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract Methods and systems for evaluation of wafers are disclosed. One example method includes illuminating a multi-crystalline wafer according to a plurality of lighting parameters, capturing a plurality of images of the multi-crystalline wafer, stacking and projecting the plurality of images to generate a composite image, analyzing the composite image to identify one or more grains of the multi-crystalline wafer, and generating a report based on the analysis of the composite image. The multi-crystalline wafer is illuminated according to a different one of the plurality of lighting parameters in at least two of the plurality of images. ## Claims ### Claim 1 A system for evaluating multi-crystalline wafers comprising: an imaging apparatus; and a computing device coupled to the imaging apparatus, the computing device comprising a processor and a non-transitory computer readable medium coupled in communication with the processor and containing instructions that, when executed by the processor, cause the processor to: capture a plurality of images of a multi-crystalline wafer in the imaging apparatus, at least two of the plurality of images illuminated in the imaging apparatus in accordance with different lighting parameters; stack and project the plurality of images to generate a composite image; analyze the composite image to identify one or more grains of the multi-crystalline wafer; and generate a report based on the analysis of the composite image. ### Claim 2 (depends on 1) A system according to claim 1, wherein the imaging apparatus comprises an imaging device and a plurality of lights positioned to illuminate a multi-crystalline wafer in the imaging apparatus. ### Claim 3 (depends on 2) A system according to claim 2, wherein the plurality of lights comprise at least a first light oriented to illuminate a multi-crystalline wafer in the imaging apparatus from a first angle and a second light oriented to illuminate the multi-crystalline wafer from a second angle different than the first angle. ### Claim 4 (depends on 3) A system according to claim 3, wherein the plurality of lights consists of four lights oriented to illuminate a multi-crystalline wafer from the first angle and four lights oriented to illuminate the multi-crystalline wafer from the second angle. ### Claim 5 (depends on 3) A system according to claim 3, further comprising a third light, wherein the first light is positioned to illuminate the multi-crystalline wafer from a first direction and the third light is positioned to illuminate the multi-crystalline wafer from a second direction different than the first direction. ### Claim 6 (depends on 2) A system according to claim 2, wherein the plurality of lights comprises at least a first light positioned to illuminate a multi-crystalline wafer in the imaging apparatus from a first height above the multi-crystalline wafer and a second light positioned to illuminate the multi-crystalline wafer from a second height above the multi-crystalline wafer different than the first height. ### Claim 7 (depends on 6) A system according to claim 6, wherein the first light is oriented to illuminate the multi-crystalline wafer in the imaging apparatus from a first angle and the second light is oriented to illuminate the multi-crystalline wafer from a second angle different than the first angle. ### Claim 8 (depends on 6) A system according to claim 6, wherein the plurality of lights consists of four lights positioned at the first height and four lights positioned at the second height. ### Claim 9 (depends on 6) A system according to claim 6, further comprising a third light, wherein the first light is positioned to illuminate the multi-crystalline wafer from a first direction and the third light is positioned to illuminate the multi-crystalline wafer from a second direction different than the first direction. ### Claim 10 (depends on 2) A system according to claim 2 wherein the plurality of lights comprises at least a first light positioned to illuminate a multi-crystalline wafer in the imaging apparatus from a first direction and a second light positioned to illuminate the multi-crystalline wafer from a second direction different than the first direction. ### Claim 11 (depends on 2) A system according to claim 2, wherein the plurality of lights comprise light emitting diodes. ### Claim 12 (depends on 2) A system according to claim 2, wherein each light of the plurality of lights comprises an array of light emitting diodes. ### Claim 13 (depends on 2) A system according to claim 2, further comprising a controller coupled in communication with the computing device and the plurality of lights, the controller configured to control a sequence of illumination of a multi-crystalline wafer in the imaging apparatus. ### Claim 14 (depends on 2) A system according to claim 2, wherein the non-transitory computer readable medium contains instructions that, when executed by the processor, cause the processor to convert the plurality of images to binary images. ### Claim 15 (depends on 2) A system according to claim 2, wherein the non-transitory computer readable medium contains instructions that, when executed by the processor, cause the processor to determine a size of each of the one or more grains of the multi-crystalline wafer identified in the composite image. ### Claim 16 A method for use in evaluating a multi-crystalline wafer comprising: illuminating a multi-crystalline wafer according to a plurality of lighting parameters; capturing a plurality of images of the multi-crystalline wafer, wherein the multi-crystalline wafer is illuminated according to a different one of the plurality of lighting parameters in at least two of the plurality of images; stacking and projecting the plurality of images to generate a composite image; analyzing the composite image to identify one or more grains of the multi-crystalline wafer; and generating a report based on the analysis of the composite image. ### Claim 17 (depends on 16) A method according to claim 16, wherein illuminating the multi-crystalline wafer according to a plurality of lighting parameters comprises illuminating the plurality of lighting parameters from at least two different angles of illumination. ### Claim 18 (depends on 16) A method according to claim 16, wherein illuminating the multi-crystalline wafer according to a plurality of lighting parameters comprises illuminating the plurality of lighting parameters from at least two different heights of illumination. ### Claim 19 (depends on 16) A method according to claim 16, wherein illuminating the multi-crystalline wafer according to a plurality of lighting parameters comprises illuminating the plurality of lighting parameters from at least two different directions of illumination. ### Claim 20 (depends on 16) A method according to claim 16, wherein analyzing the composite image further comprises determining a size of each of the one or more grains of the multi-crystalline wafer identified in the composite image.