HTCC and LTCC — How to Choose Between the Two Ceramic Packaging Routes?

I. One Letter Apart, Worlds Apart in Process

HTCC and LTCC are both “co-fired ceramics,” but that one-letter difference sends them down entirely different routes — the watershed is the sintering temperature, and with it the choice of conductor materials:

HTCC (high-temperature co-fired ceramic)— sintering temperature around 1600°C. At such temperatures only extremely high-melting tungsten and molybdenum can serve as conductors. The ceramic is dense, strong, and hermetic — the mainstay of hermetic packaging. Xuri’s HTCC ceramic substrate product line (e.g., SMT-11*9) uses a tungsten-metallized co-firing process.

LTCC (low-temperature co-fired ceramic)— sintering temperature around 850°C. At low temperature, high-conductivity conductors such as gold, silver, and copper become usable — something HTCC cannot do. Resistors and capacitors can be embedded, making it fit for high-frequency microwave modules, though its hermeticity is weaker than HTCC’s.

II. Selection Logic: HTCC for Hermeticity, LTCC for High Frequency

The boundaries of applicability for the two routes are clear:

Scenarios for choosing HTCC— where high-reliability hermeticity, high-power heat dissipation, and long-term stability are required: laser substrates, high-power device bases, aerospace packaging. The combination of alumina’s strength and tungsten conductors’ current-carrying capacity withstands harsh environments.

Scenarios for choosing LTCC— where low high-frequency loss and embedded passive components are needed: Bluetooth/WiFi modules, RF front ends. The low resistivity of gold and silver conductors sharply reduces high-frequency losses.

In one sentence: in the field of hermetic packaging, HTCC is the right choice; in RF integration, LTCC is more flexible. The two do not conflict — each holds its own ground.

[Next Episode] Next time: heat-dissipation design for high-power devices — the ins and outs of thermal management.

[Glossary]

1. HTCC (High-Temperature Co-fired Ceramic): co-fired at around 1600°C with tungsten/molybdenum conductors; hermetic and reliable

2. LTCC (Low-Temperature Co-fired Ceramic): co-fired at around 850°C with gold/silver/copper conductors; suited to high-frequency integration

3. Co-firing: the process of sintering ceramic green tape and conductor pastes into a single finished body in one firing

4. Embedded Components: the technology of integrating resistors, capacitors, and other passive components between ceramic layers