Single-Sided Substrate for High-Capacity Memory Cards
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high cost of manufacturing double-sided semiconductor packages with conductive layers on both sides limits the ability to increase the number of integrated circuit components stacked on a substrate, and existing single-sided substrates often require etching away one copper layer, which is inefficient.
Innovation Solution
A semiconductor package is formed using a single-sided substrate with a conductive layer on either the top or bottom surface, where contact fingers and bond pads are etched and plated to enable electrical connections from both sides, allowing for efficient formation of integrated circuits without the need for a double-sided structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a double-sided substrate with conductive layers on both sides is used, then electrical connections can be established from both sides, but manufacturing cost increases
Solution Approach 1:
The patent extracts the conductive layer from one side of the substrate, using a single-sided substrate with conductive material only on the top surface. This eliminates the need for bottom-side conductive layers and through-hole plating, reducing manufacturing complexity and cost while maintaining electrical connection functionality through alternative bonding methods.
Solution Approach 2:
The patent employs a cost-effective single-sided substrate structure instead of expensive double-sided substrates. By using substrates without bottom conductive layers and implementing surface-level bonding solutions, the overall manufacturing cost is reduced while achieving the required electrical connectivity for memory card applications.
2Quantity of substance
If the number of integrated circuit components stacked on substrate is increased, then storage capacity increases, but substrate cost becomes a limiting factor
Solution Approach 1:
By removing the bottom conductive layer and through-hole structure, the patent reduces substrate complexity and cost, enabling higher component density. The simplified single-sided structure allows more integrated circuit components to be stacked on the substrate without proportionally increasing substrate manufacturing costs.
Solution Approach 2:
The patent changes the substrate configuration parameter from double-sided with through-holes to single-sided with surface bonding. This parameter change reduces the substrate's structural complexity and manufacturing cost, thereby enabling increased component stacking density for higher storage capacity memory cards.
3Reliability
If copper conductive layers are used, then electrical conductivity is good, but bonding surface quality for wire bonds deteriorates
Solution Approach 1:
The patent applies different material properties to different locations: copper conductive layers provide electrical conductivity in the bulk, while gold or nickel/gold plating provides superior bonding surface quality at the contact points. This local differentiation resolves the contradiction between conductivity and bonding quality.
Solution Approach 2:
The patent uses composite material structures where copper layers are combined with gold or nickel/gold plating. The copper provides excellent electrical conductivity, while the gold or nickel/gold surface layers provide optimal bonding surfaces for wire bonds and contact fingers, achieving both requirements simultaneously.
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 approach reduces manufacturing costs and allows for the formation of high-density integrated circuits with efficient electrical connections, enabling the creation of compact flash memory devices like SD cards and memory sticks with improved reliability and capacity.
Implementation Method 1
contact fingers and bond pads are etched and plated to enable electrical connections from both sides
Data Source
AI summary
Methods of forming a semiconductor package including a single-sided substrate are disclosed. In a first embodiment of the present invention, a substrate may include a conductive layer on a top surface of the substrate, i.e., on the same side of the substrate as where the die are mounted. In a second embodiment of the present invention, a substrate may include a conductive layer on a bottom of the substrate, i.e., on the opposite side of the substrate as where the die are mounted.