Adhesion improvement of electroless copper to a polyimide film substrate by combining surface microroughening and imide ring cleavage

Abstract

In order to enhance the adhesion strength of copper metal lm to a polyimide (PI) lm substrate, a method combining surface microroughness formation and imide ring cleavage was investigated. The results showed that imide rings were cleaved with a KOH treatment while carboxyl and amide groups were formed on the surface of the PI lm. The surface micro-roughness did not change with the KOH treatment, and the adhesion strength of the copper metal lm to the PI lm was slightly improved to 30 g/ mm, which could be attributed to the interaction of both carboxyl and amide groups with the copper atoms. When the PI lms were successively treated with an alkaline permanganate and a KOH solution, many recesses were formed on the surface in an alkaline Z. Wang et al.permanganate solution, and the size and depth of the recesses increased with alkaline permanganate treatment time. The results of the AFM measurements showed that the average roughness .R/ increased from 3.54 to 10.23 nm after combined treatment with alkaline permanganate and KOH solutions. The adhesion strength of the copper metal lm to the PI lm reached 150 g/ mm, which was ve times greater than that achieved with the KOH treatment only.

Plasma cleaning of the flex substrate for flip-chip bonding with anisotropic conductive adhesive film

“…The surface microroughness can induce mechanical interlocking as well as produce a greater surface area for chemical interactions between the components of the interface. 8 Table I shows the surface roughness data for different pretreatment conditions. To understand the fracture mode, it is essential to study the fracture surface along with the peel test data.…”

Photocatalytic Surface Modification of PI Film for Electroless Copper Plating

“…The PI films were washed with distilled water after each step. The chemical composition of the electroless copper plating solution was the same as that in the literature [18], and the compositions are shown in Table 1. The pH of the solution was adjusted to 11.5 using NaOH, and the bath temperature was 70 ∘ C. After electroless plating for 40 min, the PIs were electroplated with copper at room temperature with a current density of 0.03 A/cm 2 for 1 h. The copper layer was deposited at a thickness of 20 m. After annealing at 100 ∘ C for 120 min in an oven, the copper-coated PI films were cut into 10 mm × 40 mm strips.…”

“…The surfaces of PI films are commonly modified through plasma treatment [5][6][7][8][9][10], ion implantation [11,12], chemical treatment [13][14][15][16][17][18], and UV/ozone treatment [19][20][21]. However, physical processes, such as plasma and ion implantation, require expensive equipment and are thus associated with high investment costs.…”

Nucleation Kinetics of Electroless Cu Deposition on Ruthenium Using Glyoxylic Acid as a Reducing Agent

“…10,11 ELD Cu is often considered as a method for depositing a seed layer and has previously been applied for the deposition of Cu on printed circuit boards using a Pd catalyst system. [12][13][14] Furthermore, it is attractive for replacing conventional PVD Cu seed layers in dual-damascene fabrication of Cu interconnects. [15][16][17][18] Recently, we reported a feasibility study for TSV metallization seed layer using Ru as catalytic underlayer for ELD Cu.…”