This paper summarizes the electromigration properties of thick copper lines embedded in BCB inBICMOS technologies. It is shown that activation energy in the Cu/BCB architecture is quite low, and coppermigration might preferentially occur at Cu/barrier and/or Cu/BCB interfaces. The adhesion of copper to barrierand copper to BCB or Si3N4 capping layers is determined and optimized. The increase in activation energy withincreasing interface adhesion of the Copper/embedding layer is demonstrated.

A positive-tone and aqueous-base-developable benzocyclobutene (BCB)-based dielectric material curable in air is described in this paper. The prepolymer is made from divinylsiloxane bisbenzocyclobutene (DVS-bisBCB) and BCB-acrylic acid. The formulation contains antioxidants that allow the prepolymer to cure in air and a diazonaphthaquinone to make it photosensitive. Patterned films have high resolution, and via openings are scum-free without a descum operation. Whether cured in nitrogen or in air, the prepolymer produces a film with optical, electrical, thermal, and mechanical properties desirable for many microelectronic applications, such as packaging applications and as a planarization or insulation layer in display applications

This work describes a positive-tone and aqueous-base-developable benzocyclobutene (BCB)-based dielectric material. The polymer is made from divinylsiloxane bis(benzocyclobutene) and BCB-acrylic acid. A diazonap-thoquinone in the formulation makes it photosensitive. Patterned films have high resolution, and via openings are scum-free without a de-scum operation. The material possesses optical, electrical, thermal, and mechanical properties desirable for many microelectronic applications, including as a planarization layer or an insulation layer in display, and in packaging.

The feasibility of integrating a low permittivity spin-on hardmask (SoHM) into a Cu dual damascene structure using SiLK* Semiconductor Resin (*trademark of The Dow Chemical Company) has been investigated. The study focussed on the replacement of the embedded etch stop deposited by chemical vapor deposition (CVD) by a low permittivity inorganic: film deposited by traditional spin coating. The evaluation was performed using an existing damascene test vehicle. The etch selectivity was evaluated by applying different SoHM thicknesses and etch times. The patterning chemistry used was O-2/N-2 based, in a high density TCP etch tool. The electrical data collected indicated no significant yield difference when using an embedded SoHM. The integrated k value of the SoHM film is 3.2, as compared to similar to4.0 for SiO2 films.

This work examines the mechanical performance of thin film coatings from Photosensitive-benzocyclobutene (Photo-BCB) formulations (Cyclotene2 4024, 4026 and 7200), on various substrate surfaces such as Al, Cu, Si, and SiN. The adhesion promoter used was designated AP-3000 and was based on vinyltriacetoxysilane (VTAS), which had been properly hydrolyzed and advanced. Measurement of the interfacial adhesion was performed primarily using the modified Edge Liftoff Test m-ELT. It was found that, by applying the newly developed adhesion promoter, AP-3000, the interfacial energy of Photo-BCB to Al, Cu, Si, and SiN was significantly improved, often approaching the toughness of Photo-BCB, ca. 45 J/m2. The x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) analyses of the delaminated surfaces of the Photo-BCB/Al structure revealed distinct differences in surface roughness and the chemical composition depending on whether or not adhesion promoter was used. Other parameters important for long term stability (e.g., moisture uptake and thermal stability) of Photo-BCB were also measured. The equilibrium moisture content at 84 percent RH in ambient temperature was low, 0.14 wt percent and the thermally induced weight loss at 330°C in helium atmosphere was less than 1 percent/h. The low moisture absorption and good thermal stability, together with the given mechanical toughness and adhesion, allow the Photo-BCB to be widely usable for various microelectronic packaging applications, for up to 40 μm thick build in the case of silicon substrate. [S1043-7398(00)00701-5]

The toughness of CYCLOTENE (TM) divinylsiloxane-bisbenzocyclobutene (BCB) based polymer resins from The Dow Chemical Company, is enhanced by incorporation of a second component in the polymer matrix. Thin films of modified BCB resin have significantly improved elongation at break. Excellent properties of BCB resin such as low dielectric constant and dissipation factor, low moisture up-take and higher than 350 degreesC glass transition temperature are maintained in this modified BCB material. Isothermal TGA of BCB resin with 20 wt. % additive demonstrates thermal stability of less than 1 % weight loss per hr at 325 degreesC. Residual stress of modified BCB resin thin film on a silicon wafer is about the same as BCB resin. A transmission electron micrography (TEM) study of BCB film with up to 18 wt. % of additive does not show discrete domains of the second component. At 20 % loading, some domains with approximately 0.1 mum diameter are observed. As the amount of additive increases, the size of the domains increases. Modified BCB resin formulations are photo-definable with good resolution and film retention.

Adhesion performance of coatings from Photo-BCB were investigated using a new adhesion promoter, AP-3000, based ion vinyltriacetoxysilane (VTAS) chemistry. A modified Edge Liftoff Test (m-ELT) was employed to evaluate adhesion performance of Photo-BCB on various surfaces; Si, SiN, Cu, and Al. AP-3000 resulted in a large improvement of adhesion energies for these interfaces. Atomic force microscopy (AFM) and x-ray photoelecton spectroscopy (XPS) of the aforementioned interfaces showed cohesive interfacial failure into the Photo-BCB phase. Therefore, the interfacial fracture energies approached fracture toughness of Photo-BCB, ca. 45 J/m(2).