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#146 JIS Standards on Electoless Copper Plating

Category : Electroless Plating
January18, 2013

(1) Applicable range

This standard defines electroless copper plating of 5μm or more for additive method printed circuit boards (a method of using electroless copper plating to form all or part of traces on a PCB).

(2) Types of additive methods

There are following additive methods.

1. Full Additive Method

A production method using only the electroless copper plating on adhesive applied and drilled laminated substrates to produce wiring traces on planar section and through-hole section.

2. Semi-additive Method

A method of forming planar and through-hole circuit sections by applying electroless copper plating first, then electroplating and etching on adhesive applied and drilled laminated substrates.

3. Partial Additive method

Copper clad boards are etched to form the copper circuit traces, then a plating resist pattern and electroless copper plating is applied only on the through-hole section to form the circuits.

4. Panel Additive Method

A method of using copper clad boards where the boards are drilled, electroless copper plating is applied on the entire surface including the through-hole section, then unwated copper sections are etched away to form the planar and through-hole circuits.

5. Pattern Additive Method

A copper clad board is drilled, plating resist is applied, the planar and through-hole sections are electroless copper plated, then any unwated planar sections are etched away to form the circuit traces.

(3) Grades of platings

Plating grades are classified into 2 grades based on mechanical properties as shown in [Table 1].

[Table 1] Electroless Copper Plating Grades and Mechanical Properties
GradesBase SubstratesTensile strengthElongationBending stress characteristicsNotes
Class 1Copper clad boards, Adhesive applied laminated boards, Ceramic substrates, etc.195N/mm2 or more3% or more400 times or moreGeneral purpose
Class 2295N/mm2 or more7% or more800 times or moreHigh reliability purpose

(4) Plating standards

Purity of the copper used must be 99.2% or higher based on an electrochemical purity test.

(5) Density of the plating

The copper density must be 8.7g/cm3or higher based on density test.

(6) Volume resistivity of the plating

The volume resistivity must be 2.5μΩ・cm or less at 20℃.

(7) Creation method of test specimen

The test specimen for plating purity, density, volume resistivity, tensile strength, elongation, and bending stress tests are to be of 300×300mm×0.2〜1.0t stainless steel substate, 30〜35μm electroless nickel plated and delaminated. It is to be dried for 10 minutes at 50℃ or lower after the plating.

(8) Symbols

●ELp-GE/Cu25 [1]

25μm thick class 1 electroless copper plating on glass cloth based epoxy resin copper clad substrates.

●ELp-GE/Cu35 [2]

35μm thick class 2 electroless copper plating on alumina ceramic substrates.

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