JPH0237118B2 - TASOHAISENBANNOSEIZOHOHO - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to an improvement in a method for manufacturing a multilayer printed wiring board using the AddiDave method. Conventional technology A multilayer printed wiring board is produced using the Addi-Dave method by using an insulating plate whose surface is coated with an adhesive containing a plating catalyst, forming a plating resist layer on this insulating plate, and immersing it in an electroless copper plating solution. After making an inner layer wiring board, roughening the copper surface of this inner layer circuit, and forming an insulating layer and an adhesive layer, holes for through holes are formed, and an outer plating resist layer is formed. Multilayer wiring boards are made by forming electroless copper plating layers. Problems to be Solved by the Invention During the hole-drilling process in the process of manufacturing multilayer wiring boards, smear treatment is performed because epoxy smear generated during hole-drilling affects the reliability of the through-holes. Conventionally, wiring boards were immersed in a KMnO ₄ solution, but the adhesive layer eroded and the peel strength of the electroless copper-plated conductor layer was lower than that of other multilayer wiring boards.
It has dropped by 30%. This is because the KMnO ₄ solution decomposes the NBR contained in the adhesive, epoxy resin components, and some aliphatic systems, and hydrophilic groups such as nitrile groups and carbonyl groups decrease on the surface of the adhesive layer. This is because the adhesion with the copper deposited with the electroless copper plating solution decreases. Furthermore, when using a CrO ₃ -based treatment solution, in addition to electroless copper plating treatment, the surface of the adhesive layer is roughened with a strong acid in order to improve the physical properties of copper.
Unlike when KMnO ₄ is used, the adhesive layer is not immersed, but the surface roughening treatment takes a long time, and the inner layer copper etch-backs. Means for Solving the Problems The present invention is a method for manufacturing a multilayer wiring board in which the physical properties of copper deposited on the wiring board are improved using an electroless plating solution.
KMnO ₄ and CrO ₃ solutions are used in combination. Example Using an insulating plate coated with a plating catalyst-containing adhesive on the surface, a plating resist layer was formed on the insulating plate, and the inner layer wiring board was prepared by immersing it in an electroless plating solution.
After roughening the copper surface of this inner layer circuit and sequentially laminating an insulating layer and an adhesive layer, holes were made and smear treatment liquids were prepared using Table 1 (KMnO ₄ ) and Table 2 (CrO).
After performing smear treatment in the order of Table 1 and Table 2,
After surface roughening treatment, it was immersed in an electroless plating solution to form an outer layer circuit to produce a multilayer wiring board and compare the results.

【table】

[Table] In Table 1, when the concentration of KMnO ₄ is higher than the blended value, the adhesive becomes more eroded and the adhesive becomes thinner before the smear is removed, reducing the peel strength. It was then discovered that the smear was not completely removed. Furthermore, in the case of the CrO ₃ solution shown in Table 2, it was found that when the concentration was lower than the blended value, the smear was not completely removed. Next, Table 3 shows KMnO ₄ (number 1) and CrO ₃ alone.
(No. 2) When using a solution and this KMnO ₄
The conditions are shown when the solution is sequentially treated with CrO ₃ (number 3).

[Table] In Table 3, it was found that if the treatment order of the smear treatment solution indicated by number 3 was reversed from CrO ₃ to KMnO ₄ , poor peeling of the copper foil was likely to occur. Table 4 shows the characteristics of the wiring board manufactured under the conditions shown in Table 3.
Shown below.

[Table] Effects of the Invention The present invention uses KMnO ₄ as a smear treatment liquid when performing a smear treatment when drilling holes for through holes in a wiring board, and then immerses it in a CrO ₃ smear treatment liquid. It was possible to improve the overall characteristics of peel strength, soldering heat resistance, and etchback amount of the inner layer copper.

Claims (1)

[Claims] 1 Using an insulating plate coated with an adhesive containing a plating catalyst, a plating resist layer is formed on this insulating plate, an inner layer wiring board is provided on which a circuit is formed by immersing it in an electroless plating solution, and this inner layer is coated with a plating resist layer. Insulating layer on the surface of the circuit,
After sequentially laminating adhesive layers, holes are drilled.
As a smear treatment liquid when performing smear treatment
A method for producing a multilayer printing plate by immersing it in a KMnO ₄ solution, followed by immersion in a CrO ₃ solution, and then immersing it in an electroless plating solution to form an outer layer circuit.