Rotated Stacked Die Circuit Package for Contact Access
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Solution Overview
Problem
Conventional techniques for stacking integrated circuit dies often result in obscured access to electrical contact structures, making it difficult to establish bond wire connections that satisfy spacing and clearance requirements in multi-chip configurations.
Innovation Solution
A multi-chip circuit package design where a second die is rotated by an offset angle relative to the first die, allowing horizontal and vertical access to electrical contacts, and optionally translated in the x and y directions to fit within an exclusion area defined by the first die's bond pads, thereby avoiding obscuration of bond pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a second die is stacked directly onto a first die with conventional alignment, then the vertical stacking density is improved, but access to electrical contact structures from horizontal dimensions is obscured
Solution Approach 1:
The patent applies asymmetry by rotating the second die by a non-standard angle (e.g., 30 degrees) relative to the first die, breaking the conventional symmetric alignment. This asymmetric orientation allows electrical contacts on the first die to remain accessible from horizontal dimensions while maintaining vertical stacking density, resolving the contradiction between compact stacking and contact accessibility.
2Manufacturing precision
If a smaller second die is used to provide clearance for bond wires, then bond wire spacing requirements are satisfied, but the overall package area is increased
Solution Approach 1:
The patent resolves this contradiction by introducing angular rotation as a new dimension of adjustment. Instead of reducing die size (one-dimensional solution), the second die is rotated by a non-standard angle, allowing bond wire clearance to be achieved through angular offset while maintaining full die size and minimizing package area.
3Manufacturing precision
If an offset mounting structure is used to elevate the second die, then bond wire clearance is provided, but device complexity and manufacturing steps are increased
Solution Approach 1:
The patent extracts and eliminates the need for complex offset mounting structures by using a simple angular rotation of the second die. This removes the additional manufacturing steps and structural complexity while still achieving the required bond wire clearance through the rotated orientation of the die.
4Ease of operation
If the first die is rotated by plus or minus 90 or 180 degrees to avoid covering electrical contacts, then contact accessibility is improved, but bond wire routing complexity increases
Solution Approach 1:
The patent changes the rotational parameter from standard discrete angles (90 or 180 degrees) to a non-standard continuous angle (e.g., 30 degrees). This parameter change optimizes both contact accessibility and bond wire routing by finding an angular value that simultaneously provides clear access to electrical contacts and minimizes wire routing complexity.
Data Source
AI summary
In a particular embodiment, a circuit device includes a first die coupled to a circuit substrate and having a substantially planar surface. The first die includes electrical contacts distributed on the substantially planar surface adjacent to at least three edges of the first die. The circuit device further includes a second die attached to the substantially planar surface of the first die. The second die is rotated by an offset angle about an axis relative to the first die. The offset angle is selected to allow horizontal and vertical access to the electrical contacts.