Parts manipulation and inspection system and method

• US 7,397,550 B2
• Filed: 06/29/2004
• Issued: 07/08/2008
• Est. Priority Date: 07/08/1998
• Status: Expired due to Fees

• Current Assignee: Charles A. Lemaire
• Original Assignee: Charles A. Lemaire
• Inventors: Hackney, Joshua J., Malek, Arye, Ulrich, Franz W., Estridge, John
• Primary Examiner(s): Toatley, Jr., Gregory J.
• Assistant Examiner(s): Valentin, Juan D.
• Application Number:
  US10/881,518
• Publication Number:
  US 20050111726A1
• Time in Patent Office: 1,470 Days
• Field of Search: 3562372-2375, 382/145
• US Class Current: 356/237.1
• CPC Class Codes: G01B 11/2513 with several lines being projected in more than one direction, e.g. grids, patterns
• CPC Class Codes: G01B 11/2518 Projection by scanning of the object
• CPC Class Codes: G01N 21/95607 using a comparative method
• CPC Class Codes: G03F 7/70483 Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• CPC Class Codes: H01L 21/00 Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof

Abstract

Manufacturing lines include inspection systems for monitoring the quality of parts produced. Manufacturing lines for making semiconductor devices generally inspect each fabricated part. The information obtained is used to fix manufacturing problems in the semiconductor fab plant. A machine-vision system for inspecting devices includes a light source for propagating light to the device and an image detector that receives light from the device. Also included is a light sensor assembly for receiving a portion of the light from the light source. The light sensor assembly produces an output signal responsive to the intensity of the light received at the light sensor assembly. A controller controls the amount of light received by the image detector to a desired intensity range in response to the output from the light sensor. The image detector may include an array of imaging pixels. The imaging system may also include a memory device which stores correction values for at least one of the pixels in the array of imaging pixels. To minimize or control thermal drift of signals output from an array of imaging pixels, the machine-vision system may also include a cooling element attached to the imaging device. The light source for propagating light to the device may be strobed. The image detector that receives light from the device remains in a fixed position with respect to the strobed light source. A translation element moves the strobed light source and image detector with respect to the device. The strobed light may be alternated between a first and second level.

Claims

1. A machine vision system for inspecting at least one device, the machine vision system comprising:

a machine-vision imaging device;

a first inspection station, the first inspection station comprising;

an inspection surface facing the imaging device to enable inspection of at least one device, the inspection surface having an imaged area from which the imaging device acquires an image and which has an opening therein; and

an elevator that positions at least one device within the opening in the imaged area from which the imaging device acquires the image, and wherein the elevator moves the at least one device to the imaged area from a side of the imaged area that is opposite the imaging-device side of the inspection surface, such that the imaging device acquires an image of the device while the device is on the elevator.

2. The system of claim 1, wherein the elevator further comprises a compartment for holding at least one device, the elevator placing at least one device within the opening in the surface and presenting the device to the surface for inspecting the device.

3. The system of claim 2, the first inspection station further comprising:

a light source that propagates light to the device when the device is positioned on the surface for inspecting the device; and

an image detector that receives light from the device.

4. The system of claim 2, wherein the elevator and the compartment for holding at least one device are aligned with the opening.

5. The system of claim 1, wherein the elevator is aligned with the opening.

6. The system of claim 1, further comprising:

a first tray for holding at least one device;

a first tray for holding at least one device a tray transfer mechanism; and

a second inspection station, the tray transfer mechanism operating to move at least one device from the first inspection station to a second inspection station.

7. The system of claim 6, wherein the tray transfer mechanism further comprises a tray-inverting mechanism that inverts the first tray and a second tray so as to position the at least one device within the second tray so that another side of the at least one device can be inspected.

8. The system of claim 1, further comprising:

a first output station having an elevator for holding one or more trays each of which has devices all of which have passed inspection; and

a sorting device that remove each device that has not passed inspection from a tray while the tray is located on the elevator and replaces each removed device with a device that has previously passed inspection such that trays of all good parts are held at the first output station.

9. The system of claim 7, further comprising;

a third inspection station; and

a fourth inspection station, the tray transfer device moving the device between the first and third inspection stations, and between the second and fourth inspection stations.

10. The system of claim 9, wherein the inverting mechanism is positioned between the third inspection station and the second inspection station.

11. A machine vision method for inspecting a tray populated with a plurality of devices, the method comprising:

acquiring a machine-vision image of a first device in a first tray while the first device is in an imaged area of a first inspection surface that is facing an imaging device used for the acquiring of the machine-vision image and wherein the acquiring of the machine-vision image of the first device is performed while a second tray is located directly below the first tray;

after acquiring the machine-vision image of the first device, moving the first tray away from the imaged area of the first inspection surface;

elevating the second tray from directly below the imaged area of the first inspection surface to the imaged area of the first inspection surface; and

acquiring a machine-vision image of a second device in the second tray while the second device is in the imaged area at the first inspection station.

12. The method of claim 11, wherein the first inspection surface has an opening therein, the opening accommodating one of the plurality of trays.

13. The method of claim 11, wherein the first inspection surface has an opening therein, the opening accommodating one of the plurality of trays, the trays having a rectangular shape, the method further comprising holding the trays with finger elements positioned near the opening, the finger elements engaging the long dimension side of the tray.

14. The method of claim 11, wherein the first inspection surface has an opening therein, the opening accommodating one of the plurality of trays, the trays having a rectangular shape, the method further comprising holding the trays with finger elements positioned near the opening, the finger elements engaging the short dimension side of the tray.

15. The method of claim 11, further comprising

inspecting the first tray at a second inspection surface;

moving the first tray down from a first position at the second inspection surface to a second position below the second inspection surface; and

moving the second tray to the second inspection surface and on top of the first tray.

16. The method of claim 11, further comprising:

sorting devices to remove each device that has not passed inspection from a tray while the tray is located on an output elevator; and

replacing each removed device with a device that has previously passed inspection such that trays of all good parts are output.

17. A machine vision system for inspecting at least one device, the machine vision system comprising:

a machine-vision imaging device;

a first inspection station, the first inspection station comprising;

an inspection plane facing the imaging device to enable inspection of at least a first device in a first tray, the inspection plane having an imaged area from which the imaging device acquires an image; and

an elevator configured to hold a stack of trays with the first tray at a top position in the stack of trays such that the at least first device in the first tray is positioned in the top position on the elevator and in the imaged area when the imaging device acquires the image, and wherein the elevator is configured to later position at least a second device in a second tray moved to the imaged area from a side of the imaged area opposite the imaging-device'"'"'s side of the inspection plane.

18. The system of claim 17, wherein each tray in the stack of trays comprises a plurality of compartments, each for holding at least one device, the elevator placing a tray holding a plurality of devices in a tray at the inspection surface and presenting the devices at the surface for inspecting the devices.

19. The system of claim 17, further comprising:

a first output station having an elevator for holding a stack of trays each of which has devices all of which have passed inspection; and

a sorting device configured to remove each device that has not passed inspection from a top tray at the output station and to replace each removed device with a device that has previously passed inspection, and once the top tray holds all good parts, to then lower the stack and place another top tray on the stack.