SAN FRANCISCO -- Dow Corning Corp. at the Semicon Trade show here expanded its presence in the hotly contested dielectric thin-film market with the addition of a precursor gas for chemical vapor deposition (CVD) and the rollout of the company's second-generation spin-on XLK Flowable Oxide (FOx) material.
By now offering both CVD and spin-on versions of dielectric materials for advanced IC interconnects, Dow Corning believes it has the bases covered and is giving chip makers the option to use whatever production tools they want in next-generation interconnect process technologies. "Our goal is to be a player, whether its CVD or spin-on. We're not taking positions, which is unique in this field," said Michael D. Little, business director of semiconductor fab materials for the Midland, Mich.-based company.
The selection of CVD or spin-on dielectrics for dual-damascene interconnects and copper processes has been a difficult one for IC manufacturers, which are still hunting for a good replacement of conventional silicon dioxide insulators between metal lines. CVD advocates say their approach integrates more easily into copper processes than spin-on materials, with fewer steps. Spin-on dielectric backers argue that their methods avoid the need for expensive plasma enhanced chemical vapor deposition (PECVD) tools, which can cost more than $1.5 million.
Down Corning, a 50-50 joint venture between Dow Chemical Co. and Corning Inc., claims it was the first to introduce a low-k dielectric spin-on material in 1994. The first generation FOx material has a dielectric constant of 2.9 vs. about 4.1 for conventional silicon-dioxide insulators. The second-generation XLK lowers the dielectric constant first to 2.5 with a follow-on version pushing the rating to 2.2 and then to 2.0, said Dow Corning officials at a press conference.
A third-generation spin-on material with a dielectric constant below 2.0, which will be introduced next year, said Ian S. Thackwray, executive director of Dow Corning's global electronics industry, based in Lyon, France. The new spin-on formulation and film-processes are aimed at interlevel dielectrics (ILD) applications for both copper and aluminum metal interconnects.
Dow Corning's Z3MS is a silicon source gas precursor gas for CVD dielectric used with copper or aluminum interconnect applications. It offers a dielectric constant of 2.7 using existing CVD equipment. The company has recently installed an Applied Materials Inc. CVD tool in its Semiconductor Fabrications Materials application center in Midland, Mich., to accelerate its development of materials for chemical vapor deposition.
Dow Corning is competing with one of its parent companies--Dow Chemical--which is offering a low-k spin-on material, called SiLK. This material has been selected by IBM Corp. for use in its 0.13-micron copper process technology, causing some chip makers to reconsider spin-on materials after favoring CVD (see April 3 story). Backers of CVD dielectrics--such as Applied Materials and Novellus Systems--maintain that the battle is still underway to determine the winner for low-k materials.
