Kyocera Improves 'Melting Sheet' for Sealing Chip Packages

Oct 2, 2013
Masahide Kimura, Nikkei BP Semiconductor Research
The "Torokeru (Melting) Sealing Sheet"
The "Torokeru (Melting) Sealing Sheet"
[Click to enlarge image]

Kyocera Chemical Corp will use its "Torokeru (Melting) Sealing Sheet," which it announced in 2011, as a sealing material for semiconductor chip packages.

The company will exhibit the sheet at Ceatec Japan 2013, which will take place from Oct 1 to 5, 2013, in Chiba Prefecture, Japan.

The Torokeru Sealing Sheet is a sheet-like thermo-setting epoxy resin. When it is heated on an electronic device, it is liquefied, filling gaps. Because the thermal hardening can be finished in one hour at a temperature of 100°C, a chip package can be easily sealed with an oven (See related video).

It was not possible to use the Torokeru Sealing Sheet as a sealing material for semiconductor chips. When it was liquefied to fill gaps, it tended to cause voids, lowering the reliability of the connection of wire bonding.

In the field of semiconductor packaging, there is a high demand for sheet-like encapsulation resins. In general, in the process of sealing a chip package, transfer molding, which injects resin into a mold, is used.

However, as the height of package is lowered and the size of mold is increased, it recently became difficult to inject resin. As a result, compression molding using resin powder is being increasingly used. This method requires a sheet-like resin because it is difficult to evenly spread powder.

Therefore, Kyocera Chemical made improvements to the materials of the Torokeru Sealing Sheet, developed a sheet-like resin that can be used as a sealing material for semiconductor chip packages and started to ship samples. Though the improved sheet will not be exhibited at Ceatec Japan 2013, the company plans to show it at the 43rd Internepcon Japan, which will take place from Jan 15 to 17, 2014, in Tokyo.