Etch Pit Alignment for Inter-Chip Proximity Communication
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Solution Overview
Problem
Traditional methods for assembling semiconductor chips face challenges in achieving precise alignment for proximity communication and power delivery, as they require complex and costly alignment mechanisms that are not reliable across six degrees of freedom.
Innovation Solution
The use of etch pit wells and shaped structures, such as spherical balls, prisms, or pyramids, on integrated circuit chips to facilitate precise alignment and conductive connections, allowing for capacitive coupling and power transfer between chips while enabling easy disconnection and reconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional conductive connections and wire-bonding are used for inter-chip communication, then manufacturing and packaging are simplified, but signal density and bandwidth are limited
Solution Approach 1:
The patent replaces traditional mechanical wire-bonding connections with capacitive coupling through proximity communication. This substitution enables signal transmission through electric field coupling between adjacent chip surfaces, achieving signal densities two orders of magnitude higher than wire-bonding while maintaining compatibility with standard CMOS fabrication processes
Solution Approach 2:
The invention transitions from one-dimensional wire-bonding connections to two-dimensional surface-to-surface capacitive coupling. By utilizing the entire chip surface area for communication rather than discrete bond wires, the system achieves dramatically increased signal density and bandwidth
2Quantity of substance
If proximity communication with capacitive coupling is used, then signal density and bandwidth increase significantly, but chip alignment precision requirements increase
Solution Approach 1:
The patent introduces intermediary alignment structures consisting of protrusions on one chip that fit into corresponding recesses on the opposing chip. These mechanical intermediaries provide precise alignment and positioning, ensuring that transmitter and receiver pads align both laterally and vertically with the required precision for capacitive coupling
Solution Approach 2:
The alignment structures are pre-formed on the chip surfaces during fabrication. The protrusions and recesses are created in advance with precise geometries that guide and constrain the relative positioning of chips during assembly, eliminating the need for complex real-time alignment mechanisms
3Manufacturing precision
If complex alignment mechanisms are used to achieve precise chip alignment, then alignment accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent employs self-aligning mechanical structures where protrusions on one chip automatically fit into complementary recesses on the opposing chip. This self-service alignment mechanism achieves precise positioning through simple geometric interlocking, eliminating the need for complex external alignment equipment or multi-step adjustment procedures
Solution Approach 2:
The alignment structures utilize asymmetric geometries with protrusions on one chip and corresponding recesses on the other. This asymmetric design provides unique, unambiguous alignment positions and prevents misalignment, achieving high precision with simple structural elements rather than complex symmetric mechanisms
4Loss of energy
If transmitter pads drive high-impedance capacitive loads for proximity communication, then power dissipation in driver circuits is reduced, but impedance matching becomes more challenging
Solution Approach 1:
The patent inverts the traditional approach by having transmitter pads drive high-impedance capacitive loads directly without intermediate impedance conversion stages. This reversal eliminates the need for complex impedance matching networks and associated power dissipation, as the high-impedance capacitive coupling is the fundamental transmission mechanism rather than an intermediate step
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 solution provides reliable, cost-effective, and precise alignment of semiconductor chips for proximity communication and power delivery, reducing latency and power dissipation, and allowing for flexible signal distribution and fault tolerance.
Implementation Method 1
A shaped structure is placed in an etch pit well of the first integrated circuit chip such that when the corresponding etch pit well of the second integrated circuit chip is substantially aligned with the etch pit well of the first integrated circuit chip, the shaped structure mates with both the etch pit well of the first integrated circuit chip and with the corresponding etch pit well of the second integrated circuit chip
Implementation Method 2
Besides aiding in alignment, the shaped structure also creates a conductive connection between the first integrated circuit chip and the second integrated circuit chip
Implementation Method 3
A new technique referred to as 'proximity communication' overcomes the limitations of conductive connections by using capacitive coupling to provide communications between chips which are oriented face-to-face
Data Source
AI summary
One embodiment of the present invention provides a system that facilitates precise inter-chip alignment for proximity communication and power delivery. The system includes a first integrated circuit chip, whose surface has etch pit wells. The system also includes a second integrated circuit chip, whose surface has corresponding etch pit wells configured to align with the etch pit wells of the first integrated circuit chip. A shaped structure is placed in an etch pit well of the first integrated circuit chip such that when the corresponding etch pit well of the second integrated circuit chip is substantially aligned with the etch pit well of the first integrated circuit chip, the shaped structure mates with both the etch pit well of the first integrated circuit chip and with the corresponding etch pit well of the second integrated circuit chip, thereby precisely aligning the first integrated circuit chip with the second integrated circuit chip. Besides aiding in alignment, the shaped structure also creates a conductive connection between the first integrated circuit chip and the second integrated circuit chip.