Die-to-Die Hybrid Bonding Pairing for Cu Recess Uniformity
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Solution Overview
Problem
Variations in metal recess depths during chemical-mechanical polishing (CMP) processes lead to inconsistent metal-to-metal bonding in die-to-die hybrid bonding, resulting in reduced yield and compromised electrical performance due to improper expansion during annealing.
Innovation Solution
A die-to-die hybrid bonding method and system that utilizes a distribution model, such as an AI model, to pair dies based on measured recess depths, ensuring aggregate recess depths within a predetermined range, followed by a controlled annealing process to achieve uniform bonding conditions across a batch of dies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional CMP processes are used for metal planarization, then manufacturing simplicity is maintained, but metal recess depth variations occur leading to inconsistent bonding
Solution Approach 1:
The patent applies preliminary action by measuring and characterizing metal recess depths before the bonding process, then using this information to pre-pair dies with complementary recess depth profiles. This preliminary characterization and pairing strategy ensures uniform aggregate recess depths without requiring complex real-time control during bonding.
Solution Approach 2:
The patent changes the parameter pairing strategy from random or simple sequential pairing to intelligent pairing based on measured recess depth parameters. By selecting dies with complementary recess depth values that sum to a target aggregate value, the process achieves uniform bonding conditions while maintaining manufacturing simplicity.
2Reliability
If dies with varying recess depths are bonded without pairing, then productivity is maintained, but bonding consistency and electrical performance deteriorate
Solution Approach 1:
The patent performs preliminary measurement and classification of dies by their recess depth characteristics before bonding. This upfront characterization enables efficient pairing without requiring complex real-time adjustments during the bonding process itself, thus maintaining productivity while improving reliability.
Solution Approach 2:
The patent enables the bonding system to self-adjust by automatically pairing dies based on their measured recess depth profiles. The system uses the measured data to autonomously determine optimal pairings, eliminating the need for manual intervention or complex external control systems.
3Productivity
If aggregate recess depths are not controlled within a predetermined range, then manufacturing simplicity is maintained, but metal expansion during annealing becomes improper leading to reduced yield
Solution Approach 1:
The patent changes the approach from attempting to control individual recess depths to controlling the aggregate recess depth parameter. By pairing dies whose recess depths sum to a target value within a predetermined range, the process ensures proper metal expansion during annealing while keeping the measurement and pairing system relatively simple.
Solution Approach 2:
The patent implements feedback by measuring actual recess depths, comparing them against target aggregate values, and using this information to select complementary pairing partners. This closed-loop approach ensures high bonding yield without requiring overly complex measurement systems.
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
Ensures consistent metal-to-metal bonding with improved yield and electrical performance by minimizing recess gap variations and optimizing annealing parameters for uniform process conditions.
Implementation Method 1
bonding the plurality of pairs of dies through an anneal process
Data Source
AI summary
Aspects of the present disclosure provide a die-to-die hybrid bonding method. The die-to-die hybrid bonding method includes obtaining a metal etch depth profile value for each die from a first group of dies and for each die from a second group of dies, the metal etch depth profile value of each die representing a copper (Cu) recess depth of a bonding region of the respective die; based on the metal etch depth profile values, executing a die pairing process that pairs each die from the first group of dies with a corresponding die from the second group of dies to form a plurality of pairs of dies, an aggregate metal etch depth profile value of each pair of dies being within a predetermined range; and bonding the plurality of pairs of dies through an anneal process.