Method of fabricating solid state image sensing elements

• US 5,672,519 A
• Filed: 06/06/1995
• Issued: 09/30/1997
• Est. Priority Date: 02/23/1994
• Status: Expired due to Term

• Current Assignee: Intellectual Ventures II LLC (Intellectual Ventures LLC)
• Original Assignee: LG Semico Company Limited (SK Hynix Inc.)
• Inventors: Shim, Jin Sub, Kim, Sung Ki, Song, Kwang Bok
• Primary Examiner(s): Bowers, Jr., Charles L.
• Assistant Examiner(s): Radomsky, Leon
• Application Number:
  US08/484,980
• Time in Patent Office: 847 Days
• Field of Search: 437/3, 437/53, 437/228 OP, 437/229, 216/26, 156/661.11, 430/321, 136/246, 359/619, 359/620, 359/622, 359/623, 359/626, 359/628, 257/432, 257/444
• US Class Current: 438/69
• CPC Class Codes: H01L 27/1462 Coatings
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 31/02162 for filtering or shielding light, e.g. multicolour filters for photodetectors
• CPC Class Codes: H01L 31/02327 the optical elements being integrated or being directly associated to the device, e.g. back reflectors optical coatings H01L31/0216

Abstract

This invention relates to microlenses of the solid state image sensing element and the method for fabricating the microlenses of the solid image sensing elements, which provides a solid state image sensing element including a substrate, photo diode areas each having a plurality of photo diodes in matrix array formed on the substrate, a flat area formed over the substrate including the photo diode areas, color filter layers formed in predetermined areas on the flat area, a top coating layer formed over the substrate including the color filter areas, stripe microlenses each having a flat upper surface arranged correspond corresponding to the photo diodes arranged in one direction in the photo diode areas and formed on the top coating layer, and mosaic microlenses formed on the flat upper surface of the stripe microlens each arranged corresponding to each of the photo diodes in the photo diode area.

Claims

1. A method for fabricating solid state image sensing elements comprising the steps of:

forming a passivation layer on a substrate, the substrate including photodiode areas and metal pad portions;

forming a flat layer on the passivation layer;

forming color filter layers on the flat layer;

forming a top coating layer on the substrate including the color filter layers;

forming a first photoresist on the top coating layer;

forming stripe microlens patterns over the photodiode areas by selective exposure and development of the first photoresist;

reflowing the stripe microlens patterns with heat treatment;

forming a second photoresist over the substrate, the first photoresist pattern having been formed thereon;

forming a pattern by selective exposure and development of the the second photoresist;

forming stripe microlenses by carrying out selective etching of the top coating layer and the flat layer to expose the metal pad portions together with etching of the upper part of the first photoresist pattern to a certain thickness using the second photoresist pattern as a mask;

removing the remaining second photoresist pattern;

coating a third photoresist pattern on the stripe microlenses;

forming a mosaic microlens pattern on flat upper surfaces of the stripe microlenses by selective exposure and development of the third photoresist; and

forming mosaic microlens layers by reflowing of the mosaic microlens pattern with heat treatment.

2. The method as claimed in claim 1, wherein the substrate includes photodiode areas, vertical solid state image sensing elements, and horizontal solid state image sensing elements.

3. The method as claimed in claim 1, wherein the step of forming stripe microlenses includes a step of forming microlenses having arc-shaped side surfaces.

7. The method as claimed in claim 1, wherein the substrate includes vertical solid state image sensing elements and horizontal solid state image sensing elements.

8. The method as claimed in claim 1, wherein the stripe microlens layers include arc-shaped side surfaces.

4. A method for fabrication of a solid state image sensing element comprising the steps of:

forming a first photoresist on a substrate, the substrate including metal pad portions;

forming stripe microlens patterns by selective exposure and development of the first photoresist;

reflowing the stripe microlens patterns with heat treatment to form stripe microlens layers;

simultaneously exposing the metal pad portions and flattening upper surfaces of the stripe microlens layers;

forming a second photoresist on the stripe microlens layers;

forming a mosaic microlens pattern on the flattened upper surfaces of the stripe microlens layers by selective exposure and development of the second photoresist; and

forming mosaic microlenses by reflowing the mosaic microlens pattern with heat treatment.

5. The method as claimed in claim 4, wherein the exposing and flattening step includes an etching step to expose the metal pad portions and to flatten upper surfaces of the stripe microlens layers simultaneously.

6. The method as claimed in claim 4, wherein the substrate includes color filter layers of the solid state image sensing element.