Patterned Die Backside Film for TSV Pad Access in Coreless Packages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current packaging architectures for coreless bumpless build-up Layer (BBUL) packages face challenges in accessing through silicon via (TSV) pads without damaging the silicon die and TSV pads, leading to low yield and reliability due to aggressive DBF removal processes.
Innovation Solution
The use of patterned and un-patterned die backside films (DBF) with specific adhesive chemistries, such as thermoset and thermoplastic materials, to expose TSV pads during the substrate build-up process, allowing for minimal alignment and easy access while avoiding aggressive removal methods, and subsequent chemical or thermal removal to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If aggressive DBF removal processes are used to access TSV pads, then access to TSV pads is achieved, but damage to silicon die and TSV pads occurs leading to low yield
Solution Approach 1:
The patent applies preliminary action by pre-patterned openings in the DBF that expose TSV pads before substrate build-up. This allows TSV pads to be accessible from the beginning of the process without requiring aggressive removal later, thereby preventing damage while maintaining access.
Solution Approach 2:
The DBF is segmented with patterned openings that selectively expose TSV pads while leaving other areas covered. This segmentation allows differential access - TSV pads are accessible through openings while the rest of the die backside remains protected by the DBF during build-up processes.
2Ease of operation
If DBF is removed to access TSV pads, then TSV pad accessibility is improved, but die crack and damage increase
Solution Approach 1:
Openings in the DBF are created in advance before substrate build-up, allowing TSV pads to be accessible without requiring post-build-up removal. This preliminary configuration eliminates the need for aggressive removal processes that cause die cracking.
Solution Approach 2:
The patterned DBF acts as an intermediary structure that provides controlled access to TSV pads while protecting the rest of the die. The DBF with its patterned openings serves as a mediator between the need for TSV access and the need for die protection during build-up processes.
3Ease of operation
If patterned DBF with openings is used to expose TSV pads, then alignment complexity increases, but TSV access is improved
Solution Approach 1:
The DBF is self-aligned to the die using features such as alignment marks or mechanical registration structures. The DBF performs its own alignment function without requiring complex external alignment processes, thereby exposing TSV pads while minimizing alignment complexity.
Solution Approach 2:
The DBF has different properties in different areas - patterned openings in regions requiring TSV access and solid coverage in other regions. This local differentiation allows selective TSV exposure while maintaining simple overall alignment through the use of registration features.
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
Enables high-yielding, low die crack BBUL processes with easy access to TSV pads, integrating TSV SOC and stacked memory die, and minimizing damage to silicon and TSV pads, thus enhancing packaging reliability and volume manufacturing compatibility.
Implementation Method 1
The use of patterned and un-patterned die backside films (DBF) with specific adhesive chemistries, such as thermoset and thermoplastic materials
Implementation Method 2
subsequent chemical or thermal removal to prevent damage
Data Source
AI summary
Methods of forming a microelectronic packaging structure and associated structures formed thereby are described. Those methods may include attaching a patterned die backside film (DBF) on a backside of a die, wherein the patterned DBF comprises an opening surrounding at least one through silicon via (TSV) pad disposed on the backside of the die.