Alignment Plate for Stiffener Frame Circuit Board Bonding
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Solution Overview
Problem
Conventional methods for attaching stiffener rings to semiconductor chip packages face challenges in achieving uniform adhesive bonding and restraining relative movements between the stiffener frame and the package substrate, leading to inconsistent bond line thickness and warpage due to thermal expansion mismatches.
Innovation Solution
A fixture, referred to as a bookcase, is designed with an alignment plate that has a shoulder to engage the stiffener frame's edge and a first opening with a peripheral wall to restrain the circuit board, along with a coil spring to provide uniform loading and better restraint against movement, ensuring precise alignment and consistent adhesive application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional bookcases are used to attach stiffener frames to package substrates, then the attachment process can be performed, but the relative movements between stiffener frame and package substrate cannot be sufficiently restrained, leading to inconsistent bond line thickness
Solution Approach 1:
An alignment plate is introduced as an intermediary component between the stiffener frame and the package substrate. The alignment plate includes a shoulder that engages the stiffener frame and a peripheral wall that restrains the circuit board, providing precise positioning and preventing relative movements during adhesive bonding, thereby ensuring consistent bond line thickness and reliable adhesive bonds.
2Manufacturing precision
If conventional fixtures are used without sufficient restraint mechanisms, then the attachment process is simple, but uniform adhesive bonding cannot be achieved due to relative movements
Solution Approach 1:
The fixture is segmented into distinct functional components: an alignment plate with a shoulder for engaging the stiffener frame, a peripheral wall for restraining the circuit board, and a coil spring for applying uniform loading. This segmentation allows each component to perform its specific function effectively, achieving uniform adhesive bonding while maintaining a relatively simple overall structure.
3Reliability
If sufficient restraint and uniform loading are applied to achieve desired bond line thickness, then adhesive bond quality improves, but the fixture structure becomes more complex
Solution Approach 1:
A coil spring is incorporated into the fixture to provide uniform loading across the bonding interface. The spring mechanism automatically adjusts to maintain consistent pressure and compensation for variations in component thickness, ensuring uniform bond line thickness and high adhesive bond quality without requiring a overly complex fixture structure.
Data Source
AI summary
Methods and apparatus for coupling a stiffener frame to a circuit board are disclosed. In one aspect, a method for engaging a stiffener frame and a circuit board positioned in a fixture is provided. The method includes positioning an alignment plate on the stiffener frame, such that a downwardly facing shoulder of a bottom opening of the alignment plate is seated on a setback of the stiffener frame, wherein the bottom opening of the alignment plate is larger than the a top opening of the alignment plate. The circuit board is positioned on the stiffener frame. The alignment plate restrains movement of the circuit board relative to the stiffener frame with a peripheral wall of a the top opening of the alignment plate.