LTCC Substrate Embedded Capacitors Electrode Composition
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Solution Overview
Problem
Existing low temperature co-fired ceramic substrates with embedded capacitors face issues of electrode diffusion, peeling, and loss due to inadequate control over metal composition during firing, leading to poor adhesion and bond strength between the ceramic substrate and capacitors.
Innovation Solution
A low temperature co-fired ceramic substrate with embedded capacitors is developed, featuring a first electrode with 95-100 wt % Ag and a second electrode with 65-90 wt % Ag and a higher melting point metal, along with a CaO-BaO-SiO2-B2O3-based glass, which controls the composition ratio to prevent electrode diffusion and enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If low temperature firing is used to reduce manufacturing complexity and energy consumption, then firing temperature and energy use are reduced, but electrode diffusion, peeling, and loss occur due to inadequate metal composition control
Solution Approach 1:
The patent changes the chemical composition parameters of the electrode materials, specifically formulating a multi-component metal system (Ag-Cu-Pd-W) with controlled ratios. This composition modification enables the electrode to maintain stability and adhesion during low-temperature firing by adjusting the chemical properties rather than increasing temperature
Solution Approach 2:
The patent creates a composite electrode material by combining multiple metals (Ag, Cu, Pd, W) in specific proportions. This composite structure leverages the complementary properties of each metal: Ag for conductivity, Cu for adhesion, Pd for diffusion resistance, and W for high-temperature stability, achieving reliable electrode performance at low firing temperatures
2Reliability
If Ag content in electrodes is increased to improve electrical conductivity, then conductivity improves, but electrode diffusion and peeling worsen during firing
Solution Approach 1:
The patent applies local quality by assigning different functions to different components within the electrode composite. Ag provides conductivity in specific regions, while Cu, Pd, and W provide stability and diffusion resistance in other regions. This spatial and functional differentiation allows the electrode to simultaneously achieve high conductivity and compositional stability
Solution Approach 2:
The electrode uses a composite material system where Ag (65-90 wt%) provides the primary conductivity, while Cu (5-20 wt%), Pd (5-20 wt%), and W (5-20 wt%) collectively provide compositional stability and prevent diffusion. The synergistic combination resolves the contradiction between high Ag content for conductivity and low Ag content for stability
3Ease of manufacture
If conventional electrode compositions are used to simplify manufacturing, then manufacturing is easier, but adhesion between ceramic substrate and capacitors deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrode paste to include specific ratios of Ag-Cu-Pd-W metals along with glass and ceramic powders. This parameter optimization enables strong chemical bonding between the electrode and ceramic substrate during low-temperature firing, achieving high adhesion strength while maintaining manufacturing simplicity through a standardized paste formulation
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
The substrate effectively prevents electrode peeling and loss after low temperature firing, ensuring good adhesion and bond strength between the ceramic substrate and capacitors, thereby maintaining the structural integrity and performance of the embedded capacitors.
Implementation Method 1
the low temperature co-fired ceramic substrate with embedded capacitors is able to prevent diffusion, peeling or loss of electrodes after low temperature firing by controlling composition ratio of various metals included in the substrate
Implementation Method 2
firing temperature of the low temperature co-fired ceramic substrate with embedded capacitors may be 800-950° C.
Implementation Method 3
the first electrode may further include 0.5-5 wt % of CaO—BaO—SiO2—B2O3-based glass
Data Source
AI summary
The present invention relates to a low temperature co-fired ceramic substrate with embedded capacitors. According to an embodiment of the present invention, the low temperature co-fired ceramic substrate with embedded capacitors is able to prevent diffusion, peeling or loss of electrodes after low temperature firing by controlling composition ratio of various metals included in the substrate, resulting in good adhesion between the ceramic substrate and the capacitor.