Unlock instant, AI-driven research and patent intelligence for your innovation.

Additives to prevent degradation of alkyl-hydrogen siloxanes

Inactive Publication Date: 2006-07-20
FUJIFILM ELECTRONICS MATERIALS US
View PDF17 Cites 3 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The introduction of TMCTS and similar cyclic organohydrosiloxanes into the semiconductor fab has been causing serious manufacturing challenges because these materials can polymerize unpredictably.
This behavior can be very costly and time consuming if polymerization occurs inside liquid or vapor chemical delivery lines where the only remedy is to disassemble and replace the affected lines.
The semiconductor industry demands a stable, predictable and reliable product, and this behavior is unacceptable for high volume semiconductor manufacturing.
This reaction can cause significant degradation of the siloxane, and when cyclic materials are involved, complete polymerization can eventually result, even after brief air exposure at room temperature.
Degradation of the chemical reduces shelf life, lowers product quality, and can even cause greater problems such as equipment downtime if the material polymerizes in chemical processing equipment.
Safety issues are also a concern if pressurized chemical lines and valves become blocked.
For the semiconductor industry, degradation of an organohydrosiloxane product to higher molecular weight species causes additional problems with chemical use.
This leads to several problems, including, for example, clogged transfer lines and valves and particle formation on a wafer.
The antioxidant system greatly reduces the sensitivity to air of the polysilanes.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Additives to prevent degradation of alkyl-hydrogen siloxanes
  • Additives to prevent degradation of alkyl-hydrogen siloxanes
  • Additives to prevent degradation of alkyl-hydrogen siloxanes

Examples

Experimental program
Comparison scheme
Effect test

examples

[0099] A series of tests were devised to compare the decomposition of pure TMCTS under various conditions with TMCTS that has been stabilized with additives. In these tests, approximately 5 grams of stabilized or unstabilized TMCTS sample was placed in a glass ampoule. To remove adventitious gas impurities from the sample before it was sealed, the sample was frozen in liquid nitrogen, the headspace of the ampoule was evacuated under dynamic vacuum, and then the sample was thawed under static vacuum. This process was repeated, and the sample was then flame sealed with or without a reactive gas. Control samples were sealed under vacuum, while reactive test samples were sealed under approximately 0.5 wt % of a reactive gas at ambient pressure.

[0100] The reactive gases that were used were oxygen and carbon dioxide. These gases were chosen because they are reactive components of air. Humid air was also used, and it was generated by flowing normal room air through a water bubbler in orde...

examples 1-20

[0102] Results outlined in Table 1 show that for pure TMCTS, a small amount of decomposition was observed with samples heated above 60° C. when exposed to carbon dioxide or kept under vacuum. When samples were exposed to oxygen or air, more significant decomposition was seen at all temperatures. In similar experiments using 5,000 ppm trimethylmethoxysilane (TMMOS) as a stabilizing agent, no decomposition was observed from 60 to 120° C. under vacuum or with exposure to carbon dioxide. This indicates that the TMMOS stabilizer prevented decomposition when compared to pure TMCTS under similar conditions. However, TMMOS did not stabilize TMCTS in the presence of oxygen.

TABLE 1TMCTS +100 ppmTMCTS + 0.5TMCTS + 100MHQ + 0.5Pure TMCTSwt % TMMOSppm MHQwt % TMMOSExample #T (C)Reactive Gas% Decomp% Decomp% Decomp% Decomp125Vacuum0000260Vacuum0.04000380Vacuum0.01000490Vacuum0.020005120Vacuum0.0300.060.01625CO20000760CO20.02000880CO20.02000990CO20.0200010120CO20.010.010.010.021125O20.040.000012...

examples 21-27

[0104] A range of additive concentrations was then tested to determine the minimum mount of additive necessary to stabilize TMCTS effectively. Sample of TMCTS were prepared with concentrations of MHQ from 0 to 5000 ppm. and the samples were sealed in glass ampoules under an oxygen ambient as described above. The samples were heated at 120° C. for five days, and then the total decomposition was measured in each sample by GC. The percentage of decomposition was derived by comparing gas chromatograms of samples taken before and after each experiment, where an increase in the concentration of any other species in the chromatogram indicated decomposition. The results shown in Table 2 demonstrate that a concentration of MHQ as low as 10 ppm effectively stabilizes TMCTS against decomposition. Concentrations of MHQ up to 5000 ppm were shown to be effective in stabilizing TMCTS, although solubility issues were observed at concentrations of 1000 ppm or greater of MHQ. While these concentratio...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
Temperatureaaaaaaaaaa
Temperatureaaaaaaaaaa
Temperatureaaaaaaaaaa
Login to View More

Abstract

An organohydrosiloxane composition comprising: a) one or more organohydrosiloxane compounds, each having at least one [—HSiR-O—] unit, wherein R═C1-C18 linear, branched, or cyclic alkyl, C1-C18 linear, branched, or cyclic alkoxy, or substituted or unsubstituted aryl, and b) an antioxidant compound shown in Formula (1) wherein the antioxidant compound is a phenolic compound and is present in a concentration from about 1 ppm to about 5,000 ppm and wherein R1 through R5 can each independently be H, OH, C1-C18 linear, branched, or cyclic alkyl, C1-C18 linear, branched, or cyclic alkoxy or substituted or unsubstituted aryl. The compositions of present invention exhibit stability and significantly extend the shelf life of organohydrosiloxane products and allow greater flexibility in handling these products in chemical processes or semiconductor manufacturing. The resulting stabilization of siloxanes prevents the possibility of complete polymerization (i.e., solidification) of product in chemical delivery lines or valves, which lowers equipment maintenance and costs and reduces time the machinery is out of production.

Description

RELATED APPLICATION [0001] This application claims priority from Provisional Patent Application Ser. No. 60 / 411,651 filed on Sep. 18, 2002, pending.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to siloxane compositions that exhibit stability to moisture and oxygen. More particularly, the present invention is directed to organohydrosiloxanes stabilized with one or more antioxidant compounds. [0004] 2. Description of the Prior Art [0005] 1,3,5,7-Tetramethylcyclotetrasiloxane (TMCTS) is one example of an organohydrosiloxane (i.e., constructed of [—HSiR-O—] units where R is alkyl, and in this case, methyl) that can be used for specialty polymer formation. TMCTS is an example of a cyclic organohydrosiloxane, and it has the ability to undergo ring opening polymerization. It also has reactive Si—H bonds that can be used for adding functionality to the resulting polymer. Due to these unique properties, the semiconductor industry ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): C23C16/24B32B27/00C08K5/13C08L83/04C09K3/00C23C16/44H01L21/31
CPCC08G77/12C08K5/13C08L83/04C23C16/4402Y10T428/31663C08K5/05C09K3/00C23C16/24H01L21/31
Inventor TEFF, DANIEL J.SMITH, GREGORY B.CHAGOLLA, JOHN L.ANDREYKA, TIM S.
Owner FUJIFILM ELECTRONICS MATERIALS US