Electrical and Optical Properties of Thermid Polyimide

Abstract

THERMID, made of acetylene-terminated polyimide oligomers, was developed by National Starch & Chemical Co. It is capable of forming thicker deposits than conventional polyimides. It is a candidate for a broad array of electronic and optoelectronic applications, including passivation coating, alpha-particle barrier, interlayer dielectric, encapsulation of discrete devices and IC, optical waveguide, and multilayer dielectric for thin hybrids. The study and evaluation of electrical and optical properties of THERMID polyimide give more support to their application in the semiconductor industry. DC Electrical Properties of THERMID Polyimide EL-5010 Bulk ResistivityIn order to measure the very high resistivity of THERMID, a Keithley 236 Source-Measure Unit, with current detection limit of 10 fA (DC) was used as the voltage source and current measurement equipment. A variable temperature test fixture which can effectively reduce the noise level was designed. The measurement was under the control of an IBM 386 AT personal computer (Fig.1). p-Si wafers(10-12 ohmcm) were cleaned by using RCA technique[1]. All microelectronic processing operations were performed in a class 100 clean room facility. Each Si wafer was spin coated with the THERMID thin film. The curing procedure was as follows: 180 OC ( 30 min.), 300 OC (60 min.), and 400 OC(15 min.). The back of the wafer was then sanded to get off the SiO 2 and deposited with a layer of aluminum thin film as ohmic contact. On the side coated by THERMID film, aluminium(or indium) spots were deposited. These spots served as positive electrodes in the test. The sample, which was treated as a capacitor with the THERMID as its dielectric, was then put in the test fixture and double shielded. The bulk resistivity of the THERMID was obtained by measuring the leakage current as a function of the applied voltage, the area of the contact, and the thickness of the THERMID film. The measurements revealed that the room temperature bulk resistivity of THERMID EL-5010 films of thickness of 0.96 -2.56 jum is no less than 1x10 16 ohm-cm. Temperature dependence of THERMID EL-5010 bulk resistivity was also measured (Fig.2).Breakdown Voltage When the applied step voltage was increased to such a point that the corresponding leakage current suddenly increased much faster than before, the breakdown occurred. After that point, decreasing step voltage could not make the current decreasing along the same path it increased before. The breakdown voltage of the 1 um THERMID EL-5010 thin film was measured as 350 volts.

Thermosets containing benzoxazole units: Liquid‐crystalline behavior and thermal conductivity

“…A twin‐mesogen type of BO‐containing thermoset, which is expected to have liquid crystallinity, can be obtained by introducing terminal cross‐linkable groups (X) and a flexible alkylene unit between BO‐containing mesogenic units, as represented by the following structure: X─R─BO─(CH 2 ) n ─BO─R─X, where R denotes connecting groups. Various cross‐linkable groups can be used, eg, maleimide, nadiimide (NI), 4‐ethynylphthalimide, 4‐phenylethynylphthalimide groups, benzoxazine (BOZ), and benzocyclobutene groups . In the present study, NI was chosen first as a cross‐linker because the terminal NI groups can be easily formed using a commercially available raw material, nadic anhydride (NA).…”

“…The thermal conductivity (λ) of the cured resin samples was calculated from the relationship: where R denotes connecting groups. Various cross-linkable groups can be used, eg, maleimide, 26 nadiimide (NI), 27 4-ethynylphthalimide, 28 4-phenylethynylphthalimide groups, 29,30 benzoxazine (BOZ), [31][32][33] and benzocyclobutene groups. 34 In the present study, NI was chosen first as a cross-linker because the terminal NI groups can be easily formed using a commercially available raw material, nadic anhydride (NA).…”