Side-Wettable Semiconductor Pads Using Probe Marks for Solder Inspection
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Solution Overview
Problem
Existing semiconductor packages, such as QFN and DFN, face challenges in ensuring reliable solder connections due to the difficulty in visually inspecting conductive pads, leading to increased manufacturing complexity and cost when forming side wettable pads.
Innovation Solution
The formation of probe marks on conductive pads through a probe testing process, where probes are laterally contacted and pressed to create indentations extending from the bottom to the side surface, with a deforming flange, allowing easy visual inspection of solder connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conductive pads are kept hidden on the bottom of the package, then the package structure remains simple, but it becomes difficult to visually inspect solder connections
Solution Approach 1:
The probe mark creates a vertical dimension of exposure by forming an indentation that reveals the conductive pad material from the side surface of the package. This dimensional change allows the previously hidden bottom pad to be visible from the side, enabling optical inspection without altering the overall package structure or requiring additional manufacturing steps.
2Difficulty of detecting and measuring
If special lead frame structures or additional manufacturing processes are used to create side wettable pads, then solder inspection becomes easy, but manufacturing cost and complexity increase
Solution Approach 1:
The probe testing process, which is already a necessary step in semiconductor manufacturing, is utilized to simultaneously create the side wettable probe mark. The probe's mechanical action during electrical testing automatically forms the indentation that exposes the conductive pad, eliminating the need for separate processes and making the inspection feature self-generated through existing operations.
Solution Approach 2:
The electrical testing function and the side wettable feature creation are merged into a single probe contact operation. The same probe that performs electrical verification also mechanically indents the package to create the inspection-friendly probe mark, combining two functions into one step and reducing overall manufacturing complexity.
3Difficulty of detecting and measuring
If probes are pressed against conductive pads during testing, then probe marks are formed for side wettable effect, but additional force application is required
Solution Approach 1:
The probe mark formation is performed as a preliminary action during the electrical testing stage, before the actual soldering process. By creating the indentation and exposing the conductive pad material in advance, the subsequent soldering operation can proceed normally without requiring additional force or special conditions, as the probe mark structure is already in place to guide solder flow.
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
Enables reliable solder inspection without additional manufacturing processes, reducing costs and complexity by ensuring solder adherence to side surfaces for quality assurance.
Implementation Method 1
pressing each probe against the respective conductive pad to form a probe mark thereon
Implementation Method 2
a deforming flange is formed by a pression at a periphery of the probe mark
Implementation Method 3
designed to be connected to a circuit board by soldering
Implementation Method 4
allowing an optical inspection system checks whether the package is soldered to the circuit board in a reliable way
Data Source
AI summary
A side wettable semiconductor package with probe mark has a body and multiple conductive pads. The conductive pads are arranged at intervals along edges of the body. Each conductive pad has a first surface exposed from a bottom of the body and has a second surface exposed from a side surface of the body. In an electrical test process for the conductive pads, each conductive pad is pressed by a respective probe to form a probe mark that extends to the side surface of the body. The probe mark allows solder to be easily adhered to, thereby facilitating the inspection of the solder joint on each conductive pad. The side wettable semiconductor package may be fabricated in a simple way without using a lead frame specially designed or additional processes.