Semiconductor Package Microbump Beak Formation for Void-Free Bonding
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Solution Overview
Problem
Current three-dimensional integrated circuit (3DIC) bonding techniques face challenges such as voids trapping and cold joints due to coplanarity issues with microbumps, which are exacerbated by electroplating limitations and chemical mechanical polishing inconsistencies, leading to increased costs and reduced bonding accuracy.
Innovation Solution
The proposed solution involves creating plastic and elastic deformation in microbumps during the bonding process to form beaks at the joint regions, allowing for improved alignment and contact between conductive components without prior surface planarization, thereby avoiding voids and cold joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electroplating is used to form microbumps, then conductive components can be created, but coplanarity issues arise leading to voids and cold joints
Solution Approach 1:
The patent applies preliminary action by performing surface treatment (CMP or etching) on the microbump surfaces before the bonding process. This pre-treatment ensures coplanarity and proper surface morphology are achieved prior to bonding, preventing voids and cold joints. The surface is prepared in advance with the correct characteristics needed for successful bonding.
2Manufacturing precision
If chemical mechanical polishing is used to improve coplanarity, then bonding accuracy can be enhanced, but additional process steps and costs are incurred
Solution Approach 1:
The patent merges the surface treatment step with the existing bonding process flow. Instead of adding a separate, distinct planarization step, the surface preparation (via CMP or etching) is integrated into the bonding process sequence, combining multiple functions into a unified process flow that achieves coplanarity without significantly increasing overall process complexity.
Solution Approach 2:
The patent employs cost-effective surface treatment methods such as chemical etching or standard CMP processes that are already part of the manufacturing toolbox, rather than requiring expensive specialized equipment or multi-step complex planarization sequences. These established, relatively simple processes achieve the needed coplanarity at lower cost.
3Manufacturing precision
If microbumps are made coplanar through additional processing, then bonding accuracy improves, but production time and cost increase
Solution Approach 1:
Surface preparation is performed as a preliminary step before bonding, ensuring coplanarity is achieved in advance. This allows the actual bonding process to proceed efficiently without requiring additional time-consuming adjustments or rework during the bonding operation itself, maintaining high productivity.
Solution Approach 2:
The patent changes the surface morphology parameters of the microbumps through controlled etching or CMP to achieve coplanarity. By adjusting etch conditions or CMP parameters, the desired surface flatness is obtained in a single optimized step rather than through multiple iterative processes, preserving production efficiency.
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
This method enhances bonding accuracy and reduces voids and cold joints, maintaining structural integrity while lowering production costs by eliminating the need for additional surface treatment steps.
Implementation Method 1
creating plastic and elastic deformation in microbumps during the bonding process to form beaks at the joint regions
Implementation Method 2
creating plastic and elastic deformation in microbumps during the bonding process to form beaks at the joint regions
Data Source
AI summary
The present disclosure provides a semiconductor package, including a first device having a first joining surface, a first conductive component at least partially protruding from the first joining surface, a second device having a second joining surface facing the first joining surface, and a second conductive component at least exposing from the second joining surface. The first conductive component and the second conductive component form a joint having a first beak. The first beak points to either the first joining surface or the second joining surface.