Backside thinning using ion-beam figuring

• US 5,969,368 A
• Filed: 04/27/1998
• Issued: 10/19/1999
• Est. Priority Date: 03/29/1996
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Howe, Bryan L., Thompson, Dennis A.
• Primary Examiner(s): Nguyen, Kiet T.
• Application Number:
  US09/067,485
• Time in Patent Office: 540 Days
• Field of Search: 250/492.3, 250/492.2, 250/492.1, 250/309
• US Class Current: 250/492.3
• CPC Class Codes: H01L 21/2633 for etching, e.g. sputteretching
• CPC Class Codes: H01L 27/1464 Back illuminated imager structures
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: Y10S 438/928 Front and rear surface processing
• CPC Class Codes: Y10S 438/977 Thinning or removal of substrate

Abstract

A product and process for making backside thinned semiconductor image sensing devices employing neutral ion beams to reduce substrate volumes so that the image sensor can be illuminated from the backside, or side opposite etched circuitry. A neutral ion beam is contained in a vacuum chamber that has a fixture for holding a semiconductor image sensor, a control mechanism for controlling the neutral ion beam via the raster mechanism, and a map of the semiconductor image sensor. The image sensor is placed on the fixture within the vacuum chamber and the neutral ion beam removes a predetermined amount of substrate from the backside of the sensor. The result is an image sensor than can be backside thinned at the molecular level

Claims

1. An image sensing product made from the steps comprising:

providing a semiconductor image sensor having circuits etched upon a first major surface;

providing vacuum chamber having a neutral ion beam and control means for directing neutral ion beam direction and intensity, a carrier for the image sensor, and a translation drive having means for controlling relative position of the neutral ion beam to the carrier;

placing the semiconductor image sensor within the vacuum chamber on the carrier such that the neutral ion beam will be incident upon a second major surface of the image sensor, the second major surface having no circuitry etched thereon, and being opposite the first major surface; and

etching away a predetermined thickness of the image sensor by controlling the neutral ion beam to remove a part of the second surface.

2. The product of claim 1 wherein the step of providing a vacuum chamber having a neutral ion beam further comprises providing the vacuum chamber having the neutral ion beam further comprising argon ions.

3. The product of claim 1 wherein the step of placing the semiconductor image sensor within the vacuum chamber further comprises placing within the vacuum chamber a support structure for the final chip carrier.

4. The product of claim 1 wherein the step of etching away the image sensor by controlling the neutral ion beam to remove a part of the second major surface further comprises controlling the translation drive to move the neutral ion beam in relation to the image sensor.

5. The product of claim 1 wherein the step of etching away the image sensor by controlling the neutral ion beam to remove a part of the second surface further comprises controlling the translation drive sensor in relation to the neutral ion beam.

6. The product of claim 1 wherein the individual steps are provided on a plurality of semiconductor image sensors.

7. A system for backside thinning of image sensors comprising:

a vacuum chamber;

a neutral ion beam gun contained within the vacuum chamber;

a raster mechanism operatively connected to the neutral ion beam for controlling movement of the neutral ion beam gun;

a fixture for holding a semiconductor image sensor that has etched circuitry on a first major surface such that the first major surface of the image sensor is not facing the neutral ion beam gun and a second major surface of the image sensor is facing the neutral ion beam gun;

control means for controlling the neutral ion beam via the raster mechanism to etch away the second major surface; and

a map of the semiconductor image sensor.

8. The system of claim 7 wherein the neutral ion beam further comprises an argon ion beam.

9. The system of claim 7 wherein the control means further comprises a translation drive to move the neutral ion beam in relation to the image sensor to etch away the image sensor by controlling the neutral ion beam to remove a part of the second major surface of the image sensor.

10. The system of claim 7 wherein the control means etches away the image sensor by controlling the neutral ion beam to remove a part of the second surface of the image sensor farther comprises controlling the translation drive sensor in relation to the neutral ion beam.

11. The system of claim 7 further comprising a plurality of semiconductor image sensors.