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Title: Microporous polyimide films for reduced dielectric applications

Abstract

With all the advances in the microelectronics industry, a limiting factor to computer chip speed and size is becoming the dielectric constant of the interlayer insulating materials. Dielectric constants of these layers have been reduced in going from inorganic to organic type materials. A further reduction in dielectric constant, coupled with better mechanical properties are still required for these types of materials. The authors have developed a technique involving spincoating in conjunction with a thermodynamic process called {open_quotes}Non-solvent Induced Phase Separation{close_quotes} (NSIPS) to create microporous polyimide films that exhibit both a lower dielectric constant and better stress reduction properties compared to their solid film counterparts. In this technique, the authors spincoat a soluble polyimide solution in 1,3-dimethoxybenzene solvent onto a silicon wafer, and then immediately submerse the {open_quotes}wet{close_quotes} polymer film into a non-solvent bath, typically toluene. Phase separation of the polymer occurs on a micron size scale and the resulting microporous structure becomes locked in by the high glass transition temperature of the polyimide. The authors have determined the factors affecting the film morphology, thickness, pore size, and percent porosity; these factors include the polymer concentration, spin speed, and the type of non-solvent used. The different morphologies obtained for themore » varying non-solvents are explained in terms of thermodynamics and kinetics of phase separation and diffusion, using an idealized ternary phase diagram. One particular film having a porosity of 68%, thickness of 22 microns and pore size of 1.4 microns had a measured dielectric constant of 1.88 and dielectric loss of 0.002. Stress measurements indicated that the microporous film reduced surface stress on the wafer by more than a factor of 10 when compared to the analogous solid polyimide film.« less

Authors:
; ;
Publication Date:
Research Org.:
Sandia National Labs., Albuquerque, NM (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10106624
Report Number(s):
SAND-94-2831C; CONF-941142-27
ON: DE95004543; TRN: 95:000813
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: American Society of Mechanical Engineers` winter annual meeting,Chicago, IL (United States),6-11 Nov 1994; Other Information: PBD: [1995]
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; IMIDES; DIELECTRIC PROPERTIES; ORGANIC POLYMERS; POROSITY; DIELECTRIC MATERIALS; PHASE TRANSFORMATIONS; THERMODYNAMIC PROPERTIES; CHEMICAL REACTION KINETICS; FILMS; 360606; 360601; PHYSICAL PROPERTIES; PREPARATION AND MANUFACTURE

Citation Formats

Saunders, R S, Aubert, J H, and McNamara, W F. Microporous polyimide films for reduced dielectric applications. United States: N. p., 1995. Web.
Saunders, R S, Aubert, J H, & McNamara, W F. Microporous polyimide films for reduced dielectric applications. United States.
Saunders, R S, Aubert, J H, and McNamara, W F. 1995. "Microporous polyimide films for reduced dielectric applications". United States. https://www.osti.gov/servlets/purl/10106624.
@article{osti_10106624,
title = {Microporous polyimide films for reduced dielectric applications},
author = {Saunders, R S and Aubert, J H and McNamara, W F},
abstractNote = {With all the advances in the microelectronics industry, a limiting factor to computer chip speed and size is becoming the dielectric constant of the interlayer insulating materials. Dielectric constants of these layers have been reduced in going from inorganic to organic type materials. A further reduction in dielectric constant, coupled with better mechanical properties are still required for these types of materials. The authors have developed a technique involving spincoating in conjunction with a thermodynamic process called {open_quotes}Non-solvent Induced Phase Separation{close_quotes} (NSIPS) to create microporous polyimide films that exhibit both a lower dielectric constant and better stress reduction properties compared to their solid film counterparts. In this technique, the authors spincoat a soluble polyimide solution in 1,3-dimethoxybenzene solvent onto a silicon wafer, and then immediately submerse the {open_quotes}wet{close_quotes} polymer film into a non-solvent bath, typically toluene. Phase separation of the polymer occurs on a micron size scale and the resulting microporous structure becomes locked in by the high glass transition temperature of the polyimide. The authors have determined the factors affecting the film morphology, thickness, pore size, and percent porosity; these factors include the polymer concentration, spin speed, and the type of non-solvent used. The different morphologies obtained for the varying non-solvents are explained in terms of thermodynamics and kinetics of phase separation and diffusion, using an idealized ternary phase diagram. One particular film having a porosity of 68%, thickness of 22 microns and pore size of 1.4 microns had a measured dielectric constant of 1.88 and dielectric loss of 0.002. Stress measurements indicated that the microporous film reduced surface stress on the wafer by more than a factor of 10 when compared to the analogous solid polyimide film.},
doi = {},
url = {https://www.osti.gov/biblio/10106624}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 1995},
month = {Sun Jan 01 00:00:00 EST 1995}
}

Conference:
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