Glass frit powder for sintering electronic ceramics

Glass powder is a critical material in the manufacture of MLCCs (Multi-Layer Ceramic Capacitors) and LTCCs (Low-Temperature Co-fired Ceramics).It primarily serves as a functional additive, acting as a "sintering aid" that lowers the sintering temperature—thereby enabling the co-sintering of ceramic and metal electrodes—and optimizes the product's overall performance.

A.       Applications and Effects in MLCCs

In MLCCs, the application of glass powder is present in both the dielectric layer and the terminal electrodes .

Application areas	core role	Specific effects
Dielectric layer material	Achieving co-firing with copper internal electrodes	- Lowering the sintering temperature : Reduce the sintering temperature to 600°C-750°C to avoid oxidation of the copper electrode. - Matching thermal expansion : By adjusting the coefficient of thermal expansion (CTE), match it with the ceramic matrix such as barium titanate ( BaTiO₃ ) to reduce defects such as delamination and warping.
	Optimize electrical performance	- Maintain high dielectric constant : To meet the high capacitance requirements of MLCCs. - Reduce dielectric loss : To form a dense microstructure, improving Q value and high-frequency performance.
Terminal electrode paste	Enhanced adhesion and compatibility	- Improved adhesion : The glass additives melt during sintering, forming a glass layer between the metal powder particles that promotes sintering. This creates a strong transition layer between the end electrode and the ceramic substrate. - Ensures compatibility : The glass prevents reactions with the ceramic substrate and other components, providing a chemically stable interface. This ensures long-term stability of the electrode and substrate. stability.
	Improve reliability	- Improved chemical stability : Prevents corrosion from plating solutions during electroplating, resulting in defects such as cracks. - Reduced internal stress : Reduces internal stress after sintering, improving reliability such as solderability.

 

Requirements for glass powder in MLCCs:

Typical glass composition:

1.        Borosilicate glass :

It has a high melting point and good chemical stability, which helps to suppress shrinkage during the sintering process.

2.        Phosphate glass :

It exhibits excellent adhesion and sintering properties, forming a good interface between the electrode and the ceramic substrate.

3.        Oxide glass :

It has high curing performance and excellent thermal stability, making it suitable for the sintering process of MLCCs.

Technological Challenges and Prospects:

1.      of glass composition : In order to optimize the conductivity and sintering characteristics of the electrode, the composition of the glass must be precisely adjusted.

2.      Cost reduction : While using high-performance glass, it is also necessary to select materials and improve processes in order to reduce costs.

3.      Environmental protection : More environmentally friendly materials and manufacturing processes are under development.

 

B.       Applications and Effects in LTCC

In LTCC, glass powder also plays a dual role as a " sintering aid " and a " performance regulator ".

• Core function: Achieving low-temperature co-firing : This is the cornerstone of LTCC technology. Low-melting-point glass powder is added to ceramic powder (such as Al₂O₃ ). During sintering, the glass softens, driving the entire system to densify at around 850°C , thus allowing the use of low- melting - point , highly conductive metals such as silver and gold as electrodes.
• Performance Tuning: Optimization and Customization :

1.      Excellent adhesion: Glass provides good adhesion between the ceramic substrate and the metal electrode. As a result, the electrode layer adheres firmly to the substrate, improving mechanical strength.

2.      Maintaining conductivity : The glass composition of the electrode paste plays a role in maintaining the conductivity of the electrode after sintering. An appropriate glass composition will not impair the conductivity of the metal powder and can improve the sintering characteristics.

3.      Shrinkage Control: In the LTCC process, glass additives are used to control the shrinkage of the ceramic and electrode layers. This ensures dimensional accuracy and improves product quality.

4.      Chemical stability : Glass is chemically stable, preventing reactions with ceramic substrates and metal materials, thus ensuring the long-term stability of electrodes and substrates.

5.      Low dielectric loss: By using glass with a high dielectric constant, the high-frequency characteristics of LTCC devices are improved and signal loss is reduced.

Typical glass composition

1.      Lead- based glass :

Lead is easy to sinter at low temperatures and has good melting and adhesion properties. However, due to environmental regulations restricting the use of lead, people are now exploring alternative materials.

2.      Barium - based glass :​

It has a high dielectric constant and good low-temperature sintering characteristics, which improves the performance of LTCC equipment.

3.      Phosphate glass :

It has good sinterability and bonding properties, providing a stable interface between the metal electrode and the ceramic substrate.

4.      Silicate Glass :​​

It has good heat resistance and chemical stability, and excellent sintering characteristics at low temperatures.

 

Shanghai Canal is the authorized distributor of TOMATEC glass frit powder products from Japan. We design and customize various glass frit powders to meet the needs of MLCCs, LTCCs, and other ceramic electronic components, module substrates, etc.