Picosecond laser processing method for bonding pad at bottom of blind slot

By combining tin plating and laser ablation with alkaline etching, the problem of insufficient processing accuracy of the bottom pattern of the blind groove depth was solved, achieving high-precision blind groove bottom pattern formation, ensuring product conductivity and space saving.

WO2026129529A1PCT designated stage Publication Date: 2026-06-25SHANGHAI MEADVILLE ELECTRONICS
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Patent Information

Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
SHANGHAI MEADVILLE ELECTRONICS
Filing Date
2025-04-28
Publication Date
2026-06-25

AI Technical Summary

Technical Problem

Existing technologies make it difficult to achieve pattern processing at the bottom of the deep trench in blind trenches, and conventional etching methods cannot achieve the required precision, resulting in unclear pattern edges, large dimensional deviations, or failure to form complete patterns.

Method used

By combining tin plating with laser ablation and alkaline etching, and through picosecond processing with a disk bonded to the bottom of the deep trench, a blind trench bottom pattern is formed. Using inner layer adhesive tape and outer layer peeling technology, combined with machining and electroplating, a high-precision blind trench bottom pattern is formed.

Benefits of technology

It achieves high-precision pattern processing at the bottom of the blind slot, ensuring conductive connection between inner and outer layers, saving product space and reducing product volume. It also protects the inner layer pattern through tin plating and alkaline etching, and completes the pattern formation in other areas.

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Abstract

Disclosed is a picosecond laser processing method for a bonding pad at a bottom of a blind slot, comprising tin layer stripping: a circuit board to be tin-stripped is placed in a tin stripping solution to ensure that a tin layer is completely immersed. According to characteristics of the tin stripping solution and specific conditions of a circuit board, setting an appropriate tin stripping time and temperature, and gently brushing a surface of the circuit board with a brush to help remove the tin layer; full-board dry film application: cutting a dry film to appropriate dimensions to ensure that the dry film completely covers the circuit board. A design providing a bonding pad at a bottom of a controlled-depth slot facilitates a conductive connection between inner and outer layer products, allowing components to be embedded in the controlled-depth slot, optimizing product space and minimizing product volume, and the controlled-depth slot is formed on a rigid board by utilizing inner layer taping and removing an outer layer cover; since slot-bottom pads cannot be patterned using conventional etching methods, the present invention solves this problem by using a tin plating method and laser ablation to form a pattern; secondary tin plating - alkaline etching is then used to protect the inner layer pattern while completing pattern formation for other regions.
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