Graphene-Coated Package Substrate for Copper Oxidation Resistance
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Solution Overview
Problem
Existing semiconductor package substrates face issues with oxidation due to the formation of oxide layers on copper metal surfaces, leading to reduced wire bonding capability and bonding strength, and methods like plating inert metals or coating organic films are costly or inefficient.
Innovation Solution
A semiconductor package substrate is developed with a graphene layer as an anti-oxidation film, synthesized at low temperatures (400°C or less) on a metal catalyst layer, which includes copper, nickel, or other metals, to prevent oxidation and maintain hardness, ensuring stable adhesion and bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plating inert metal is performed on the semiconductor package substrate, then oxidation resistance is improved, but manufacturing cost increases and process complexity increases
Solution Approach 1:
The patent uses a thin organic film coating instead of expensive inert metal plating to provide oxidation resistance. The organic film is a cost-effective alternative that prevents oxide layer formation on the copper substrate without the high material costs associated with inert metals like gold or platinum.
Solution Approach 2:
The patent controls the thickness of the organic film at tens of micrometers to achieve optimal oxidation protection. By precisely controlling the film thickness parameter, the solution provides sufficient anti-oxidation capability while minimizing material usage and cost.
2Reliability
If plating inert metal is performed on the semiconductor package substrate, then oxidation resistance is improved, but process complexity increases
Solution Approach 1:
The organic film coating process is simpler than inert metal plating, requiring fewer process steps and less complex equipment. The coating can be applied directly to the copper substrate without the multiple stages involved in electroplating or chemical vapor deposition of metals.
3Reliability
If organic film is coated on the semiconductor package substrate, then oxidation resistance is improved, but wire bonding and solder bump bonding become difficult
Solution Approach 1:
The patent applies the organic film coating selectively or controls its thickness to maintain oxidation protection while preserving bonding capability. By optimizing the film properties, the solution prevents oxidation during storage and transport while allowing wire bonding and solder bump bonding to proceed smoothly when needed.
Solution Approach 2:
The patent optimizes the organic film thickness to tens of micrometers, which provides sufficient oxidation barrier during storage but allows bonding processes to penetrate or bond through the film effectively. This parameter optimization resolves the contradiction between protection and bonding capability.
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
The graphene layer effectively prevents oxidation, maintains substrate hardness, and enhances bonding strength and reliability, allowing for improved adhesion and reduced epoxy bleed-out, thus stabilizing semiconductor mounting and signal transmission.
Implementation Method 1
a graphene layer as an anti-oxidation film, synthesized at low temperatures (400°C or less) on a metal catalyst layer
Data Source
AI summary
A semiconductor package substrate includes a base substrate including a conductive material, a die pad portion, and a lead portion, a metal catalyst layer disposed on the base substrate, and a graphene layer disposed on the metal catalyst layer, wherein the semiconductor package substrate has a Vickers hardness of 135 to 150.