Browse Prior Art Database

Infrared Curing of Polyimide Precursors

IP.com Disclosure Number: IPCOM000034680D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Pawlowski, WP: AUTHOR [+2]

Abstract

Disclosed is a process for fully curing polyimide and photosensitive polyimide precursors using short wavelength infrared (IR) radiation. Total process time is reduced from a couple of hours to minutes. A very uniform etchable polyimide is formed. During the curing of polyamic acid (I), water is split out and polyimide (II) is formed (Fig. 1). This process is known as imidization. In the convection oven curing process, 2-3 hours, the polyamic acid is cured from top to bottom resulting in a tough skin forming on top of the polyimide. Penetration by hydroxide is extremely difficult and etching of the polyimide requires very concentrated base, hydrazine hydrate or other exotic chemicals. The rate determining step of imidization is the loss of hydrogen from the amide linkage, which occurs at a wavelength of 2-3 microns.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 88% of the total text.

Page 1 of 2

Infrared Curing of Polyimide Precursors

Disclosed is a process for fully curing polyimide and photosensitive polyimide precursors using short wavelength infrared (IR) radiation. Total process time is reduced from a couple of hours to minutes. A very uniform etchable polyimide is formed. During the curing of polyamic acid (I), water is split out and polyimide (II) is formed (Fig. 1). This process is known as imidization. In the convection oven curing process, 2-3 hours, the polyamic acid is cured from top to bottom resulting in a tough skin forming on top of the polyimide. Penetration by hydroxide is extremely difficult and etching of the polyimide requires very concentrated base, hydrazine hydrate or other exotic chemicals. The rate determining step of imidization is the loss of hydrogen from the amide linkage, which occurs at a wavelength of 2-3 microns. Low wavelength, quartz-tungsten infrared curing furnaces emit energy in that wavelength region, greatly accelerating the imidization process. The IR radiation uniformly attacks the -N-H bonds, forming a uniform polyimide. No tough film is formed on the surface allowing a more dilute hydroxide to penetrate the polyimide matrix, easily etching it without drastic chemicals and conditions. Analysis of the mechanical properties show that ease of etching is not due to a less well-packed structure.

(Image Omitted)

Photosensitive polyimide precursors (III and IV) can also be IR cured to form polyimide (V) via a similar...