Method for producing hermetic package
A technical object of the present invention is to devise a method by which bonding strength between an element base and a sealing material layer can be increased without thermal degradation of a member to be housed inside, to thereby improve long-term reliability of a hermetic package. A method of producing a hermetic package of the present invention includes the steps of: preparing a ceramic base and forming a sealing material layer on the ceramic base; preparing a glass substrate and arranging the ceramic base and the glass substrate so that the glass substrate is brought into contact with the sealing material layer on the ceramic base; and irradiating the sealing material layer with laser light from a glass substrate side to seal the ceramic base and the glass substrate with each other through intermediation of the sealing material layer, to thereby provide a hermetic packages.
1. A method of producing a hermetic package, the method comprising the steps of:
preparing a ceramic base and forming a sealing material layer on the ceramic base;
preparing a glass substrate and arranging the ceramic base and the glass substrate so that the glass substrate is brought into contact with the sealing material layer on the ceramic base; and
irradiating the sealing material layer with laser light from a glass substrate side to seal the ceramic base and the glass substrate with each other through intermediation of the sealing material layer, to thereby provide a hermetic package,
wherein the ceramic base comprises a base part and a frame part formed on the base part and the sealing material layer is formed on a top of the frame part, and
wherein the forming a sealing material layer is performed by applying and firing a sealing material paste to form a sealing material layer formed of a sintered body of a sealing material on the ceramic base.
2. The method of producing a hermetic package according to claim 1 , wherein the sealing material layer is formed on the ceramic base after subjecting the top of the frame part to polishing treatment.
3. The method of producing a hermetic package according to claim 2 , wherein the top of the frame part has a surface roughness Ra of less than 0.5 μm after the polishing treatment.
4. The method of producing a hermetic package according to claim 1 , wherein the sealing material to be used comprises 55 vol % to 95 vol % of bismuth-based glass and 5 vol % to 45 vol % of a refractory filler.
5. The method of producing a hermetic package according to claim 1 , wherein the sealing material layer has an average thickness of less than 10 μm.
6. The method of producing a hermetic package according to claim 1 , wherein the ceramic base and the sealing material layer have a difference in thermal expansion coefficient of less than 45×10 −7 /° C., and the sealing material layer and the glass substrate have a difference in thermal expansion coefficient of less than 45×10 −7 /° C.
7. The method of producing a hermetic package according to claim 1 , further comprising producing the ceramic base by sintering a green sheet laminate.