Lead Frame and Clip Frame Layout for Larger Die Pad Area
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Solution Overview
Problem
Conventional power semiconductor packages face issues with space consumption due to clip attachment, slow and costly soldering processes, and additional equipment requirements for bond wires, which affect die area utilization and manufacturing efficiency.
Innovation Solution
A lead frame and separate clip frame design where leads are monolithically formed with the die pad and clip, allowing for planar protrusion without vertical overlap, eliminating the need for separate lead posts and reducing the number of attachment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal clip is used to connect the source terminal to a lead post of the lead frame, then electrical connectivity is achieved, but the clip landing zone consumes space on the lead frame, reducing die area utilization
Solution Approach 1:
The invention extracts the clip from the traditional lead frame structure and repositions it to contact the source terminal directly on the die surface. This removes the need for a separate lead post and clip landing zone, thereby freeing up lead frame area for larger die attachment while maintaining the electrical connection function.
Solution Approach 2:
The clip is repositioned from a vertical arrangement (lead post extending upward from lead frame) to a horizontal arrangement (clip contacting source terminal on die surface). This dimensional change eliminates the vertical overlap between leads and allows all leads to protrude in generally planar directions from the mold compound.
2Reliability
If soldering or diffusion soldering is used to attach the clip to the lead frame, then secure electrical connection is achieved, but the process is slow and costly
Solution Approach 1:
The invention combines the clip attachment process with the die attachment process. Both the die and the clip are attached to the lead frame in a single manufacturing step, eliminating the need for separate soldering operations. This merging of processes significantly improves manufacturing speed and reduces costs while maintaining secure electrical connections.
3Reliability
If bond wire is used to contact the gate terminal, then electrical connectivity is achieved, but additional process steps and equipment investment are required
Solution Approach 1:
The invention makes the clip frame multi-functional by enabling it to contact multiple terminals (source and gate terminals) directly. This eliminates the need for separate bond wire processes for gate terminal contact, reducing the number of process steps and equipment requirements while maintaining reliable electrical connections to all necessary terminals.
Data Source
AI summary
A molded semiconductor package includes a lead frame having one or more first leads monolithically formed with a die pad and extending outward from the pad in a first direction. A semiconductor die is attached to the die pad at a first side of the die. A metal clip of a clip frame is attached to a power terminal at a second side of the die. One or more second leads monolithically formed with the metal clip extend outward from the clip in a second direction different than the first direction. A mold compound embeds the die. The first lead(s) and the second lead(s) are exposed at different sides of the mold compound and do not vertically overlap with one another. Within the mold compound, the clip transitions from a first level above the power terminal to a second level in a same plane as the leads.