Low-K Films

Low-K (Low Dielectric Constant) Film

Low-κ (low dielectric constant) films are commonly used as insulators because of their ability to prevent crosstalk on integrated circuits (ICs). This low dielectric constant allows for fast switching speeds and more components within a single chip when compared to silicon dioxide.

Typical Low-κ Application Methods:

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

Black Diamond I, II, and III

Produced by Applied Materials

There are three generations of Black Diamond film listed below:

1. Original Black Diamond (Also called BD1) (k~3.0), is the industry-standard for the 90/65nm nodes. Creating nano-porous low-k film is a two-step process consisting of PECVD deposition of an organosilicate glass “backbone” and a thermally labile organic phase, followed by an ultraviolet (UV) cure that removes the labile phase—thereby inducing porosity—and restructures and strengthens the remaining silicon-oxide matrix to form the final nano-porous film. Small average pore size and tight pore size distribution eliminate the need for pore sealing.

2. The Black Diamond II (Also called BD2) nano-porous low-k film is the industry standard for the 45/32nm copper/low-k interconnects, with a k-value of approximately 2.5.

3. The next-generation Black Diamond III (Also called BD3) film extends this industry-leading technology to ultra-low-k (ULK) film (k~2.2) for scaling to 22nm and below and improving device speed. It also imparts the mechanical strength (hardness and elasticity) required by emerging advanced packaging schemes. The film exhibits excellent moisture resistance, stable k-value after etch and photoresist removal, and superior mechanical strength.

Chemical formula: SiCOH

Κ= 2.2– 3.0

This low-κ film is produced by introducing -CH3to a silica substrate to produce a hybrid dielectric material, SiOC:H.

This is fabricated using CVD near room temperature with an organosilane precursor along with oxygen and nitrous oxide as an oxidant instead of hydrogen peroxide.

Black Diamond low-κ coatings are beneficial because the substrate will be able to maintain the same thermo-mechanical properties as silicon oxide, with much faster switching speeds and improved insulation.