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Material Science and Technology of Japan, 55㸦2018㸧36㹼40Feb. 2018

Regular Paper
Direct Pattern Formation by Electroless Anisotropic Growth Copper
Plating on Liquid Crystal Polymer Using Selective UV Irradiation
Aung Myin OO1,2, Mitsuhiro WATANABE2, Hideo HONMA2 and Osamu TAKAI1, 2
1

Graduate School of Engineering, Kanto Gakuin University, 1-50-1 Mutsuura-Higashi, Kanazawa-Ku,

Yokohama, Kanagawa 236-8501, Japan

2

Material & Surface Engineering Research Institute, Kanto Gakuin University, 1162-2 Odawara-shi,Ogikubo 250-0042, Japan

Received Dec. 23, 2017; accepted for publication Jan. 14, 2018
Abstract
Plating on plastic materials technology is widely applied in electronics-related fields. The choices of the electronicmaterials with the low dielectric properties are required for high-speed transmission and high frequency compatible circuit
formation. Conventionally, in the transmission characteristics, the state of the interface between the resin and theconductor is important. However, although adhesion between the conductor and the resin is obtained by an anchor effect inthe size of micrometers, it makes a factor of loss in high frequency transmission. A metal film with smooth surface can beformed by surface modification with ultraviolet (UV) irradiation and this technique led us to the examination of selective
deposition with the UV irradiation. For this reason, it is desired to form a conductor on the smooth surface of the resin.
Moreover, full-additive method was examined in order to reduce the number of steps of circuit formation and anisotropic
growth plating technique is required. In this experiment, we found that a possibility of circuit formation by using inhibitor
as pre-treatment to control the horizontal growth during plating.
Keywords: Direct Pattern Formation, Electroless Copper Plating, Anisotropic Growth, UV Irradiation

1.

Introduction

to solve this problem, we have reported that reforming method

The information society was become in last recent years,on various resin surfaces with nanometer level by UV irradiationand the demands of high performance electronic devices havetechnique and follow the plating on reformed surface. For thebeen increasing more and more. In printed circuit boards, circuit

above background, we studied to form a circuit by selectivelyformation was suitable for high frequency and high-speed

deposition of anisotropic electrolless copper plating aftertransmission was desired. For this reason, it is strongly

irradiating ultraviolet where circuit is formed only the part of UV

recommended to use an excellent dielectric characteristics

ray exposed [3]. Therefore, low dielectric properties of liquidmaterial, to form a circuit in which the influence of the skin

crystal polymer materials were used. Normally, plating direction

effect is reduced. Nowadays, the circuit formation on thewas grows equally not only in the vertical but also in theinsulating resin is adhered by a rough surface of several

horizontal direction. Anisotropic growth plating is one of themicrometers. This is the so-called anchor effect. This surface

plating methods that deposits preferentially in one direction.

roughness greatly affects the loss in signal transmission. InIn this experiment, we examined that the selective

recent years, examination of circuit formation by anchor-less has

deposition and anisotropic electroless copper plating on thebeen actively conducted. Moreover, an ideal circuit formationsmoothwas suitable for low conductor loss is a circuit formation on a(2-MBT) inhibitor [4] as a pretreatment and confirmed its effect.

smooth resin surface. However, circuit formation on a smooth

2-MBT is known as a stabilizer, but it also has the effect ofsurface poses have a big problem in adhesion progress. In ordersuppressing the deposition reaction. By using this effect,*Corresponding author: (m16J6002@kanto-gakuin.ac.jp)(36)

surfacebyadditionof

2-Mercaptobenzothiazole