Hermetic bonding of glass to metal, called GTMS(Glass To Metal Sealing), is one of Yamamura Photonics’ oldest core technologies. In this first column, we present a four-part series on the glass-to-metal hermetic bonding technology we have developed over the years.

GTMS Products　　　　　　　　　　　　TO-Cap　　　　　　　　　　　　　　Glass LID

Among Yamamura Photonics’ product range, glass-to-metal sealing technology (GTMS: Glass to Metal Sealing) is applied to glass processed products (GTMS products) and optical components (TO-Cap, Glass LID). This technology is a method of adhering glass to metal by heating it to a temperature higher than the transition point of the glass, enabling high hermeticity to be achieved. Yamamura Photonics has two technologies for joining glass and metal directly and using low-melting-point sealing glass, but several conditions need to be met to achieve hermetic sealing and reliable bonding.

◆ Important conditions for hermetic bonding of glass and metal

1. Thermal properties must be consistent between the parts to be joined.

2. Appropriate surface treatment and oxide film formation on the metal parts.

3. A diffusion layer of metal oxide is formed in the glass by appropriate heating during bonding.

The above three conditions must be met in order to hermetically bond glass and metal.
Each of these conditions will be introduced in more detail in the next issue.