Stacked Microelectronic Devices Void-Free Die Attach
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional stacked microelectronic devices face mechanical and electrical connection failures due to air bubbles and voids formed by underfill materials, leading to unreliable connections between stacked dies during high-temperature processes.
Innovation Solution
A stacked microelectronic device configuration with an attachment feature, such as a film-over-wire die attach film, provides a void-free mechanical and electrical connection between dies, eliminating the need for underfill material and enhancing package reliability by using preformed films or tapes that ensure a robust connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If underfill material is used to connect stacked dies, then mechanical support is provided, but air bubbles and voids form causing connection failures
Solution Approach 1:
The patent removes the underfill material from the stacked die configuration, extracting the harmful element that causes air bubbles and voids. The dies are directly attached to each other through wire bonds without any underfill material, eliminating the source of connection failures while maintaining mechanical support through the wire bond structure itself.
Solution Approach 2:
The patent uses thin wire bonds as flexible conductive elements to provide both mechanical support and electrical connection between stacked dies. The wire bonds act as thin film structures that can accommodate thermal expansion and mechanical stress without forming voids, replacing the problematic underfill material.
2Productivity
If multiple dies are stacked to increase capacity, then device performance improves, but mechanical and electrical connection failures increase
Solution Approach 1:
The patent merges the mechanical support function and electrical connection function into a single integrated wire bond structure. The wire bonds simultaneously provide mechanical attachment between dies and electrical connectivity, eliminating the need for separate underfill material and reducing points of failure in stacked die configurations.
Solution Approach 2:
The wire bond structure serves itself by providing both mechanical support and electrical connection without requiring additional underfill material. The wire bonds self-organize to provide both functions, eliminating the harmful air bubbles and voids that occur with traditional underfill methods.
3Stability of the object's composition
If underfill material is used to support stacked dies, then mechanical stability is improved, but void formation occurs during high-temperature processes
Solution Approach 1:
The patent extracts and removes the underfill material from the stacked die assembly, eliminating the source of air bubbles and voids that form during high-temperature processing. The wire bond structure provides mechanical stability without the harmful byproducts associated with underfill curing.
Solution Approach 2:
The patent replaces the problematic underfill material with simple wire bonds that can be easily formed and removed. The wire bonds serve as temporary yet sufficient mechanical support during assembly and provide permanent electrical connection, avoiding the long-term reliability issues of underfill material degradation.
Data Source
AI summary
Packaged microelectronic devices and methods for manufacturing packaged microelectronic devices are disclosed herein. In one embodiment, a packaged microelectronic device can include a support member, a first die attached to the support member, and a second die attached to the first die in a stacked configuration. The device can also include an attachment feature between the first and second dies. The attachment feature can be composed of a dielectric adhesive material. The attachment feature includes (a) a single, unitary structure covering at least approximately all of the back side of the second die, and (b) a plurality of interconnect structures electrically coupled to internal active features of both the first die and the second die.