Wiring Lead Organic Coating Prevents Resin Burrs
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Solution Overview
Problem
The formation of resin burrs during the injection-molding of semiconductor devices and LED devices leads to issues with electrical connection strength, adhesion, and manufacturing efficiency, as well as problems with silicone resin thermal shrinkage, Ag plating discoloration, and outgas contamination affecting wire bonding and luminous efficiency.
Innovation Solution
A wiring lead with a surface organic coating containing purine skeleton compounds is used, which enhances resin adhesion, prevents resin burr formation, and improves the adhesion between silicone resin and the wiring lead, while also protecting Ag plating from discoloration and outgas contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If injection molding is performed to encapsulate semiconductor elements with wiring leads, then electrical connection and packaging are achieved, but resin burrs are formed on peripheral regions of the wiring lead
Solution Approach 1:
A release agent is applied to the wiring lead before injection molding to prevent resin adhesion. This preliminary action ensures that when the molding is completed, resin burrs do not form on the wiring lead peripheral regions, eliminating the need for subsequent burr removal processes while maintaining electrical connection integrity
Solution Approach 2:
A release agent serves as an intermediary substance between the resin and the wiring lead. This intermediary prevents direct adhesion between the resin and metal surfaces, allowing clean separation after molding without generating resin burrs that would compromise electrical connections
2Manufacturing precision
If resin burrs are removed by spraying high pressure liquid or roughening die surface, then resin burr removal is achieved, but manufacturing complexity and additional process steps are increased
Solution Approach 1:
The release agent is applied beforehand to prevent resin burr formation in the first place. This preliminary preventive measure eliminates the need for subsequent burr removal operations such as high pressure liquid spraying or die surface roughening, thereby simplifying the overall manufacturing process
Solution Approach 2:
The problem of resin burr formation is addressed by extracting the root cause (resin adhesion to wiring lead) rather than treating the symptom (burr removal). By removing the adhesion mechanism through release agent application, the entire burr removal process chain is eliminated
3Reliability
If silicone resin is used for encapsulation, then adhesion and sealing are improved, but thermal shrinkage occurs affecting electrical connection
Solution Approach 1:
The release agent is applied before silicone resin encapsulation to create a controlled interface. This preliminary action allows the silicone resin to adhere properly to intended surfaces while preventing adhesion to wiring leads, compensating for thermal shrinkage effects by establishing proper bonding geometry before shrinkage occurs
Solution Approach 2:
The release agent creates local quality differences on the wiring lead surface - areas covered by the release agent remain non-adhesive while other areas maintain adhesion capability. This localized control allows silicone resin to adhere where needed while preventing thermal shrinkage-induced connection problems at critical electrical interface regions
4Reliability
If Ag plating is applied to wiring lead, then electrical conductivity and solderability are improved, but discoloration occurs during resin molding
Solution Approach 1:
The release agent acts as an intermediary protective layer between the Ag plating and the resin environment. This intermediary prevents chemical reactions and thermal degradation that cause discoloration, while allowing the Ag plating to maintain its electrical conductivity and solderability functions
Solution Approach 2:
The release agent is applied to protect the Ag plating before the resin molding process begins. This preliminary protection prevents discoloration during molding, preserving the aesthetic and functional quality of the Ag plating while maintaining electrical performance
5Ease of manufacture
If resin molding is performed without release agent, then manufacturing simplicity is maintained, but resin burrs form and adhesion problems occur
Solution Approach 1:
The release agent enables self-service separation between the resin and wiring lead after molding. The wiring lead automatically releases from the resin without requiring external force or complex ejection mechanisms, achieving clean separation and preventing resin burr formation while maintaining manufacturing simplicity
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 solution effectively prevents resin burrs, ensures strong electrical connectivity, maintains adhesion, and enhances luminous efficiency by stabilizing the resin and Ag plating, thus improving manufacturing efficiency and reducing defects.
Implementation Method 1
an organic coating disposed to cover a surface of the metal plate, the organic coating containing a plurality of compounds each having a purine skeleton
Implementation Method 2
enhances resin adhesion, prevents resin burr formation, and improves the adhesion between silicone resin and the wiring lead
Data Source
AI summary
The present invention aims to make possible facile removal of resin burrs without the risk of damaging resin body covering a wiring lead in a semiconductor device. In detail, the semiconductor device 10 has a structure in which a semiconductor element is mounted on the wiring lead 10, the wiring lead 10 including a metal plate with metal coating applied to the outer surface thereof. The peripheral region 15 of the wiring lead 11 is covered with an organic coating including purine skeleton compounds. The organic coating is formed through the self-assembling of functional organic compounds each having a structure in which a purine skeleton has at an end thereof a functional group having a metal bonding property.