Suspension Board Circuit Pattern End Alignment for Laser Soldering
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Solution Overview
Problem
Conventional suspension boards with circuits face challenges in accurately positioning laser beam irradiation and solder ball placement, leading to thermal decomposition of insulation layers and functional issues with magnetic heads due to exposure of insulation layers to the laser beam and dispersion in solder ball positions.
Innovation Solution
The suspension board design features a pattern end with a stepped-part structure on the insulation layer, where the end face of the pattern end is aligned or protrudes from the insulation layer, and the inner wall of a penetrating opening is aligned or retracted beneath the insulation layer, creating a stable position for the solder ball and suppressing direct laser irradiation on the insulation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the magnetic head and connection terminals are made smaller to improve integration, then the device complexity is reduced, but the positioning precision of laser beam irradiation and solder ball placement deteriorates
Solution Approach 1:
The patent introduces an intermediary structure (the insulation layer with specific thickness and the opening) that mediates between the small terminal dimensions and the laser beam irradiation requirements. This intermediary structure provides a reference surface that enables accurate laser positioning despite the reduced size of the magnetic head and terminals.
Solution Approach 2:
The patent performs preliminary action by forming the insulation layer with a specific thickness and creating an opening before the laser irradiation step. This preliminary structure serves as a positioning reference that guides the laser beam to the correct location, ensuring accurate solder ball melting even with reduced terminal sizes.
2Ease of manufacture
If the insulation layer is exposed to the laser beam during solder ball melting, then the solder ball can be melted to establish connection, but the insulation layer undergoes thermal decomposition producing harmful carbon deposits
Solution Approach 1:
The patent extracts the harmful function by removing the insulation layer from the laser irradiation zone. By forming an opening that exposes only the necessary area for solder ball melting while keeping the insulation layer covered elsewhere, the harmful thermal decomposition is prevented while maintaining the necessary manufacturing function.
Solution Approach 2:
The patent converts the potential harm of laser irradiation on the insulation layer into a benefit by using the opening structure to control exactly where irradiation occurs. The opening allows the laser to melt the solder ball while the surrounding insulation layer remains protected, turning a potentially harmful process into a controlled beneficial one.
3Ease of repair
If solder balls are placed to connect magnetic head terminals, then the magnetic head can be replaced independently, but the positioning of solder balls becomes dispersed and difficult to control
Solution Approach 1:
The patent introduces the opening structure as an intermediary that mediates between the solder ball placement and the terminal connection requirements. This intermediary provides a precise positioning reference that reduces dispersion in solder ball positions while maintaining the ability to replace magnetic heads independently.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design ensures accurate solder ball placement, reduces thermal decomposition, and minimizes the risk of laser beam irradiation on the insulation layer, thereby enhancing the reliability and performance of magnetic head connections.
Implementation Method 1
supplying a solder ball 150 in contact with both terminal surfaces. Then, a laser beam is irradiated on the ball to melt it as shown in FIG. 9(b) with a reference number 151 to establish a connection.
Data Source
AI summary
An area 5 for mounting a magnetic head is formed on a metal board 1, a conductive layer 4 is formed as a circuit pattern via an insulation layer 2 interposed outside this area and up to a metal board 1. A pattern end 4 to be a connection terminal for connection with the terminal of the magnetic head is formed on the circuit pattern, an end face 4a of the pattern end 4 is aligned with an end face 2a of the insulation layer 2 directly beneath it or protruded in the terminating direction from the end face 2a, thereby providing a structure preventing irradiation of a laser beam on the insulation layer 2.