Semiconductor Package Pad Recesses to Prevent Solder Ball Overflow
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Solution Overview
Problem
Conventional semiconductor packages face reliability issues due to solder ball diffusion during miniaturization, leading to circuit shorts and mounting problems, as the conventional structure lacks adequate protection against overflow of connection parts like solder balls.
Innovation Solution
A semiconductor package design featuring a first insulating layer with recessed pads and a second insulating layer that includes openings to prevent overflow of connection parts, with the recess acting as a dam to stabilize the connection parts and improve chip mounting reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the circuit pattern layer is miniaturized to mount multiple chips on one circuit board, then the chip mounting area is reduced and signal transmission path is shortened, but solder ball diffusion occurs causing reliability problems such as circuit shorts
Solution Approach 1:
The invention divides the circuit board structure into multiple layers with insulating layers separating conductive elements. The circuit pattern is segmented across different layers (first circuit pattern layer and second circuit pattern layer) with insulating layers in between, preventing solder ball diffusion from causing shorts while maintaining miniaturization benefits.
Solution Approach 2:
The invention transitions from a two-dimensional planar arrangement to a three-dimensional multi-layer structure. By stacking circuit pattern layers and insulating layers vertically, the design achieves higher density mounting while using the vertical dimension to isolate conductive elements and prevent solder ball diffusion issues.
2Speed
If the circuit pattern layer is miniaturized to mount multiple chips on one circuit board, then high-speed signal transmission is enabled through short path, but solder ball diffusion occurs leading to reliability problems
Solution Approach 1:
The multi-layer structure segments the circuit into distinct conductive layers separated by insulating layers. This segmentation allows for optimized signal paths in each layer while the insulating layers act as barriers preventing solder ball diffusion, thus maintaining both high-speed transmission and reliability.
Solution Approach 2:
The insulating layers serve as intermediary elements between conductive circuit patterns. These intermediaries provide electrical isolation and physical barriers that prevent solder ball diffusion while allowing the circuit to maintain its miniaturized, high-speed design.
3Ease of manufacture
If conventional semiconductor package structure is used, then manufacturing is simpler, but solder ball diffusion causes reliability problems
Solution Approach 1:
The invention segments the package structure into modular layers (circuit pattern layers and insulating layers) that can be manufactured and assembled systematically. This layered approach, while slightly more complex than conventional single-layer designs, provides reliable prevention of solder ball diffusion through the insulating barriers.
Solution Approach 2:
The invention uses composite structure combining conductive circuit patterns with insulating materials in alternating layers. This composite approach integrates the functionality of both conductive pathways for signal transmission and insulating barriers for preventing solder ball diffusion, achieving improved reliability.
Data Source
AI summary
A semiconductor package according to an embodiment includes a first insulating layer; a first pad disposed on an upper surface of the first insulating layer; a second pad disposed on an upper surface of the first insulating layer and spaced apart from the first pad in a horizontal direction; and a second insulating layer disposed on the first pad and including a first opening overlapping an upper surface of the first pad in a vertical direction, wherein an upper surface of the second pad includes a recess, and wherein the recess of the second pad is closer to a lower surface of the first insulating layer than the upper surface of the first pad.