Method for fabricating surface acoustic wave filter packages and package sheet used therein
A method for fabricating Surface Acoustic Wave filter packages uses a package sheet having an outline pattern and anti-bur holes. In the package sheet for a Surface Acoustic Wave filter package, the outline pattern is formed along outer peripheries of chip mounting areas where a plurality of SAW filter chips are to be mounted. The outline pattern is contacted with a metal shield layer formed on the SAW filter chips and a predetermined region of the package sheet. Circular anti-bur holes are located at the corners of the chip mounting areas and on cutting lines along which the sheet is to be singulated into individual SAW filter packages.
1. A method of fabricating Surface Acoustic Wave (SAW) filter packages, the method comprising the steps of:
preparing a plurality of SAW filter chips and a package sheet, wherein the package sheet has
an outline pattern of a predetermined width formed along outer peripheries of predetermined chip mounting areas where the SAW filter chips are to be mounted, and
circular anti-bur holes formed at corners of the chip mounting areas;
mounting the SAW filter chips on the package sheet;
forming a protective layer on the SAW filter chips on the package sheet;
removing predetermined portions of the protective layer between the SAW filter chips to expose the outline pattern on the package sheet and predetermined portions of the package sheet between the SAW filter chips;
forming a metal shield layer on the SAW filter chips, the exposed portions of the package sheet and the outline pattern; and
cutting the package sheet along predetermined cutting lines extending through the anti-bur holes between the SAW filter chips to form a plurality of SAW filter packages.
2. The method as set forth in claim 1 , wherein the outline pattern is formed on the package sheet with a predetermined length corresponding to the outer peripheries of the SAW filter chips.
3. The method as set forth in claim 1 , wherein each of the anti-bur holes has a predetermined size to cover all adjacent corners of the corresponding chip mounting areas.
4. The method as set forth in claim 1 , wherein the package sheet comprises at least two sheet layers.
5. The method as set forth in claim 4 , wherein the anti-bur holes are formed in at least one sheet layer of the at least two sheet layers, the one sheet layer having a surface for mounting the SAW filter chips.
6. The method as set forth in claim 1 , wherein the SAW filter chips are provided on undersides thereof with bumps for mounting the SAW filter chips.
7. The method as set forth in claim 1 , wherein the protective layer comprises a photosensitive film.
8. The method as set forth in claim 7 , wherein the step of removing predetermined portions of the protective layer is carried out by dry etching.
9. A Surface Acoustic Wave filter package fabricated according to the method as set forth in claim 1 .
10. The method as set forth in claim 1 , wherein the outline pattern has multiple concave cut-outs defined by peripheral edges of the anti-bur holes.
11. A method of fabricating Surface Acoustic Wave (SAW) filter packages, the method comprising the steps of:
preparing a plurality of SAW filter chips and a package sheet, wherein the package sheet has
an outline pattern of a predetermined width formed along outer peripheries of predetermined chip mounting areas where the SAW filter chips are to be mounted, and
anti-bur holes formed at corners of the chip mounting areas;
mounting the SAW filter chips on the package sheet;
forming a protective layer on the SAW filter chips on the package sheet;
removing predetermined portions of the protective layer between the SAW filter chips to expose the outline pattern on the package sheet and predetermined portions of the package sheet between the SAW filter chips;
forming a metal shield layer on the SAW filter chips, the exposed portions of the package sheet and the outline pattern; and
cutting the package sheet along predetermined cutting lines extending through the anti-bur holes between the SAW filter chips to form a plurality of SAW filter packages.