Low Dielectric Constant Films

In order to improve the performance of computer chips and reduce the delay of back-end interconnections and to insulate these interconnections, researchers have gradually used interlayer dielectric (ILD) materials with lower and lower dielectric constants. Alfa Chemistry has the ability to provide customers with various low dielectric constant (low-k) films on wafers. This low-k film can prevent crosstalk on integrated circuits (ICs). Compared to silicon dioxide, the low dielectric constant allows faster switching speeds and more components in a single chip.

What Can Alfa Chemistry Provide?

We provide (not limited to) the following low-k films:

Silsesquioxane (SSQ) Based Films

Alfa Chemistry prepares SSQ-based films by adding specific thermally stable pore formers to the precursor. There are two ways to introduce the pore former into the precursor: ① Disperse the pore former directly in the solution. Commonly used pore formers include block copolymers, surfactants and organic nanospheres; ② The sacrificial particles are grafted into the polymer network through chemical bonds, which fundamentally controls the pore distribution of the film.

SiO₂ Based Films

Most CVD low-k films are doped in SiO₂: Replace the Si-O bond with the less polar Si-F bond to obtain SiOF; Introduce CH₃ groups to get SiOCH. The introduction of F and C also increases the distance or free volume of the central atom of SiO₂, which reduces k. Alfa Chemistry uses fluorosilicide precursors, such as SiH₂F₂ and (CH₃)_xSiHy, prepared by CVD to introduce F or C. The methods for producing elimination-type porous SiOCH films by CVD include multi-phase deposition and chemical etching of constitutive porous films.

Organic Polymer Films

The electronic polarization of organic polymers is small and has the lowest k value. It includes polyimides, parylenes, and polyolefin chains. Alfa Chemistry can further reduce the k value by introducing pores into organic polymers. The main methods are block copolymerization and graft copolymerization. Porous organic polymers are strong competitors for ultra-low dielectric constant media.

Nanoporous SiO₂ Films (Aerogel and Xerogel)

Based on the different drying methods, dry gels and aerogels with different properties can be obtained. Alfa Chemistry's sol-gel technology can form nano-holes in thin films in two ways: one is to use aging, and the other is to rely on the self-assembly of sol particles.

Typical Low-k Application Methods

• Chemical Vapor Deposition (CVD): k values >2.5
• Spin-On: k values < 2.5, porous films (< 65nm)

Our methods and equipment

We use the following equipment to obtain data:

Alfa Chemistry's Technical Strengths