Automated substrate handling and film quality inspection in solar cell processing

• US 8,318,512 B2
• Filed: 04/28/2010
• Issued: 11/27/2012
• Est. Priority Date: 04/29/2009
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Shah, Vinay K., Kumaraswami, Suresh, Cox, Damon K.
• Primary Examiner(s): Roman, Angel
• Application Number:
  US12/769,517
• Publication Number:
  US 20100279439A1
• Time in Patent Office: 944 Days
• Field of Search: 438/15, 414/222.01, 901/30
• US Class Current: 438/15
• CPC Class Codes: H01L 21/67155 Apparatus for manufacturing or treating in a plurality of work-stations
• CPC Class Codes: H01L 21/67259 Position monitoring, e.g. misposition detection or presence detection

Abstract

The present invention generally provides an apparatus and a method for automatically calibrating the placement of fragile substrates into a substrate carrier. Embodiments of the present invention also provide an apparatus and a method for inspecting the fragile substrates prior to processing to prevent damaged substrates from being further processed or broken in subsequent transferring steps. Embodiments of the invention also generally provide an apparatus and a method for determining the alignment and orientation substrates that are to be delivered into or removed from a substrate carrier. Embodiments of the invention further provide an apparatus and method for accurately positioning the substrate carrier for substrate loading. The substrate carriers are generally used to support a batch of substrates that are to be processed in a batch processing chamber.

Claims

1. A solar cell formation process, comprising:

positioning a substrate carrier having an array of substrate receiving positions on a carrier receiving surface;

positioning a substrate on a substrate receiving surface of an end effector of a robot;

determining an actual position of the substrate on the substrate receiving surface of the end effector, wherein determining the actual position comprises;

emitting electromagnetic radiation towards a surface of the substrate and the substrate receiving surface of the end effector; and

receiving a portion of the emitted electromagnetic radiation at a defined wavelength reflected from the surface of the substrate and the substrate receiving surface of the end effector by a detector, wherein the detector uses the received portion of the emitted electromagnetic radiation to form a first image; and

positioning the substrate in one of the array of substrate receiving positions, wherein positioning the substrate comprises adjusting the placement of the substrate using the information received from the first image.

2. The process of claim 1, wherein positioning the substrate carrier comprises:

placing the substrate carrier on the carrier receiving surface;

detecting reference features located on the substrate carrier with a vision system; and

determining an actual position and orientation of the substrate carrier using information received from the vision system.

3. The process of claim 2, wherein the reference features include identification information unique to the substrate carrier.

4. The process of claim 1, wherein positioning the substrate carrier comprises:

transporting the substrate carrier from a known position to a default position and orientation on the carrier receiving surface;

viewing the substrate carrier with a vision system;

determining an actual position and orientation of the substrate carrier using information received from the vision system;

determining an offset between the actual position and orientation and the default position and orientation; and

repositioning the substrate carrier on the carrier receiving surface using the offset.

5. The process of claim 1, further comprising determining if the substrate has a defect therein using information found in the first image.

6. The process of claim 1, further comprising:

repositioning the substrate on the substrate receiving surface of the end effector;

determining the actual position of the repositioned substrate on the substrate receiving surface of the end effector, wherein determining the actual position of the repositioned substrate comprises;

emitting electromagnetic radiation towards the surface of the substrate and the substrate receiving surface of the end effector; and

receiving a portion of the emitted electromagnetic radiation at the defined wavelength reflected from the surface of the substrate and the substrate receiving surface of the end effector by the detector, wherein the detector uses the received portion of the emitted electromagnetic radiation to form a second image; and

repositioning the substrate in the one of the array of substrate receiving positions, wherein the repositioning the substrate in the one of the array of substrate receiving positions comprises adjusting the placement of the substrate using information received from the first and second images.

7. The process of claim 1, further comprising:

transferring a substrate into each of the array of substrate receiving positions on the substrate carrier; and

transferring the substrate carrier into a processing module.

8. A solar cell formation process, comprising:

positioning an end effector of a robot in a nominal position over a first substrate disposed in one of an array of substrate receiving positions on a substrate carrier;

receiving the first substrate on the end effector while the end effector is in the nominal position;

determining an actual position of the first substrate positioned on the end effector using a detection system;

calculating an offset of the actual position from an expected position of the first substrate on the end effector;

calculating a new nominal position using the offset and storing the new nominal position in memory of a system controller;

receiving a second substrate on the end effector;

positioning the end effector in the new nominal position; and

depositing the second substrate in the one of the array of substrate receiving positions.

9. The process of claim 8, wherein the determining the actual position comprises:

emitting electromagnetic radiation towards a surface of the first substrate and a surface of the end effector; and

receiving a portion of the emitted electromagnetic radiation at a defined wavelength reflected from the surface of the first substrate and the surface of the end effector by a detector, wherein the detector uses the received portion of the emitted electromagnetic radiation to form a first image.

10. The process of claim 9, wherein information from the first image is used to calculate the offset.

11. The process of claim 10, further comprising determining an actual position of the second substrate on the end effector, comprising:

emitting electromagnetic radiation towards a surface of the second substrate and the surface of the end effector; and

receiving a portion of the emitted electromagnetic radiation at a defined wavelength reflected from the surface of the second substrate and the surface of the end effector by the detector, wherein the detector uses the received portion of the emitted electromagnetic radiation to form a second image.

12. The process of claim 11, wherein information from the second image is used in positioning the end effector in the new nominal position.

13. The process of claim 12, wherein the defined wavelength is selected so that it is absorbed by a material disposed on the surface of the first and second substrates.

14. The process of claim 13, further comprising determining if the second substrate has a defect therein using information from the second image.

15. The process of claim 12, further comprising:

positioning the substrate carrier in a default position on a carrier receiving surface;

viewing features of the substrate carrier with a vision system;

determining an actual position and orientation of the substrate carrier using information received from the vision system;

determining an offset between the actual position and orientation and the default position and orientation; and

repositioning the substrate carrier on the carrier receiving surface using the offset.

16. The process of claim 12, further comprising:

positioning the substrate carrier on a carrier receiving surface;

viewing features of the substrate carrier with a vision system; and

determining an actual position and orientation of the substrate carrier using information received from the vision system.

17. A solar cell processing system, comprising:

a robot having an end effector configured to receive a substrate;

a detection system comprising;

an electromagnetic radiation source configured to emit electromagnetic radiation at one or more desired wavelengths;

a detection assembly that is positioned to receive at least a portion of the emitted electromagnetic radiation reflected from a surface of a substrate disposed on the end effector of the robot; and

one or more walls that are adapted to at least partially enclose the electromagnetic radiation source and the detection assembly; and

a system controller configured to receive a signal from the detection assembly regarding the position of the substrate that is disposed on the end effector of the robot and determine an actual position of the substrate with respect to the end effector.

18. The system of claim 17, wherein the system controller is further configured to determine an offset between the actual position of the substrate and a desired position of the substrate.

19. The system of claim 18, wherein the system controller is further configured to transfer the substrate to a substrate receiving position in a substrate carrier using the offset.

20. The system of claim 19, wherein the system controller is further configured to determine if a defect exists on the surface of the substrate based on information received from the detection assembly.