HTCC vs LTCC: Differences, Materials and How to Choose

HTCC (high-temperature co-fired ceramic) and LTCC (low-temperature co-fired ceramic) both build multilayer ceramic circuits by printing conductors on unfired ceramic tape, stacking and laminating the layers, and firing ceramic and metal together. The difference is the firing temperature, and it decides everything else. HTCC fires alumina-based tape at a high temperature, so its buried conductors must be refractory metals such as tungsten or molybdenum; the result is strong, thermally better and well suited to hermetic packages. LTCC fires a glass-ceramic below the melting point of silver and copper, so it can use low-resistance silver, gold or copper conductors; the result suits RF modules and circuits with buried passive components, but conducts heat poorly. If your board only needs to carry heat and current, a metallized ceramic such as DPC, DBC or AMB is usually a better fit than either. This guide compares the two and shows how to choose.

1. HTCC vs LTCC at a Glance

	HTCC	LTCC
Ceramic	Alumina-based (often around 90–96% Al2O3)	Glass-ceramic or glass plus alumina filler
Firing temperature	High; commonly around 1,500°C or above	Low; below about 1,000°C
Buried conductors	Tungsten, molybdenum (refractory, higher resistance)	Silver, gold, copper (low resistance)
Thermal conductivity	Close to alumina, about 15–25 W/(m·K)	Low, typically a few W/(m·K); needs thermal vias
Strength	High	Lower
Buried passives	Limited	Resistors, capacitors and inductors can be built in
Typical uses	Hermetic packages, sensor and laser packages, harsh environments	RF and microwave modules, radar and wireless front ends, sensors

Silver melts at 961°C and copper at 1,085°C, which is why only a low-temperature ceramic can fire together with them; HTCC’s higher firing temperature rules them out for buried layers. Exact firing profiles and material values depend on the tape system, so get them from the supplier for the material you will use.

2. How Is a Co-Fired Ceramic Made?

Kyocera describes the sequence (Kyocera co-fired packaging overview):

1. Punch vias and cavities in sheets of unfired (“green”) ceramic tape.
2. Fill vias with conductor paste and print circuit patterns on each sheet.
3. Stack and laminate the sheets.
4. Fire, so the ceramic and metal densify together.
5. Plate exposed metal, add finishes, braze leads or seal rings, and assemble.

The ceramic shrinks during firing, so artwork is scaled before firing and finished dimensions depend on the tape system. Some LTCC processes constrain in-plane shrinkage (Orbray LTCC). Specify finished dimensions and tolerances, not shrinkage.

3. What Do Real HTCC Material Values Look Like?

MARUWA’s HTCC substrates, as one example, use 92% alumina with tungsten in vias and inner layers:

Property (MARUWA HTCC, white / brown grade)	Value
Alumina content	92%
Inner conductors	Tungsten
Thermal conductivity	16 / 15 W/(m·K)
CTE	7.0 / 7.3 ppm/°C
Dk at 1 GHz	9.0 / 9.1

Source: MARUWA alumina multilayer substrates and packages. This is lower than the 24–26 W/(m·K) of a 96% alumina substrate because the composition differs. LTCC values vary more between tape systems, so compare the datasheets of the specific tapes you are offered.

4. When Should You Choose LTCC?

• RF and microwave circuits where conductor loss matters: silver or gold conductors have much lower resistance than tungsten.
• Integrated passives: filters, couplers, baluns and embedded resistors and capacitors in the layers.
• Compact multilayer modules combining RF, control and sensing.
• Lower dielectric constant than alumina, which helps at high frequency.

Watch the heat path: LTCC conducts heat poorly, so power devices need thermal vias, a heat-spreading insert or a different substrate. Our ceramic RF design guide covers layout rules.

5. When Should You Choose HTCC?

• Hermetic packages for sensors, lasers, optical and high-reliability electronics; HTCC alumina bodies are strong and take brazed leads and seal rings. Egide describes HTCC packages for RF and harsh environments on its HTCC technology page.
• Mechanical strength and better thermal conductivity than LTCC.
• High-temperature or harsh environments.

The trade-off is conductor resistance: tungsten and molybdenum have several times the resistivity of silver or copper, which matters for RF loss and high current. Hermeticity is a property of the finished, sealed package, so ask for seal test evidence on the complete part.

6. When Do You Need Neither?

Co-fired ceramic is for buried layers and packages. If the job is to carry heat and current from a power device or LED, a fired ceramic substrate with copper added afterwards is usually simpler and better:

Need	Better fit
Heat spreading under LEDs, fine lines, plated vias	DPC
Thick copper for power modules	DBC
Thick copper with severe thermal cycling	AMB, often on silicon nitride
Simple printed circuits on ceramic	Thick film or thin film

See our guides to DPC vs DBC, thick film vs thin film, and the seven ceramic PCB manufacturing processes.

7. What Should You Specify for a Co-Fired Part?

Item	What to write
Process and tape system	HTCC or LTCC, and the specific tape and paste system, or “supplier to propose”
Layers	Number of layers, cavities, buried passives
Conductors	Buried metal and surface finish, separately
Electrical	Frequency, impedance, insertion loss targets
Thermal	Power to dissipate and the heat path
Dimensions	Finished dimensions, flatness and tolerances
Sealing	Hermetic requirement and test method on the complete package
Tests	Electrical, dimensional, seal and environmental tests

Cost depends on layer count, cavities, conductor metal, tooling and volume; co-fired parts carry more tooling than metallized substrates. Our ceramic PCB price breakdown covers cost drivers.

How Can We Help?

We build both HTCC and LTCC parts, as well as DPC, DBC and AMB metallized ceramic boards in alumina and aluminum nitride. Send your requirements and we will recommend the route that fits, including whether a metallized ceramic would do the job more simply; bare-board quotes come back within 2 hours. See our ceramic PCB manufacturing page and ceramic PCB guide.

Conclusion

HTCC fires alumina at high temperature with tungsten or molybdenum conductors, giving strong, thermally better parts for hermetic packages. LTCC fires a glass-ceramic below the melting point of silver and copper, giving low-loss conductors and buried passives for RF modules, but a poor heat path. If the board mainly carries heat and current, use DPC, DBC or AMB instead. Specify the tape system, conductors, dimensions, sealing and tests. We make both HTCC and LTCC; contact us to discuss your design.

FAQ

What is HTCC? High-temperature co-fired ceramic: alumina-based layers fired together with refractory metal conductors such as tungsten, used mainly for hermetic packages.

What is LTCC? Low-temperature co-fired ceramic: glass-ceramic layers fired together with silver, gold or copper conductors, used mainly for RF modules and integrated passives.

What is the main difference between HTCC and LTCC? Firing temperature, which sets the conductor metal: refractory metals for HTCC, low-resistance metals for LTCC.

Which has better thermal conductivity? HTCC, because it is mostly alumina; LTCC glass-ceramics conduct heat poorly.

Which is better for RF? LTCC usually, because its conductors have lower resistance and its dielectric constant is lower.

Does QueenEMS make HTCC and LTCC? Yes, both, as well as DPC, DBC and AMB ceramic boards.