Patent ID: 7183124

Claim:
A method of manufacturing a surface mount SAW device, the surface mount SAW device comprising: a mounting substrate that includes an insulating substrate, an external electrode for surface mount arranged on a bottom of the insulating substrate, and a wiring pattern arranged above the insulating substrate and said external electrode; a SAW chip that includes a piezoelectric substrate, an IDT electrode formed on one surface of the piezoelectric substrate, and a connection pad connected to said wiring pattern through a conductor bump; and a sealing resin that is formed to cover the SAW chip from an outer surface of the SAW chip to an upper surface of the mounting substrate while mounting said SAW chip on the mounting substrate in a face-down state by flip-chip bonding, and that thereby forms an airtight space between said IDT electrode and said mounting substrate, the method comprising: a flip-chip mounting step of connecting said wiring pattern to said connection pad through said conductor bump, thereby mounting the SAW chip on said mounting substrate by the flip-chip bonding; a lamination step of mounting a resin sheet, larger in an area than an upper surface of said SAW chip, on the upper surface of the SAW chip, and pressurizing the resin sheet while softening or melting the resin sheet from one end of the mounting substrate to the other end of the mounting substrate, thereby covering the outer surface of the SAW chip with a resin while securing said airtight space; a press molding step of pressurizing and heating the SAW chip having the outer surface laminated with said resin, thereby hardening the resin while suppressing expansion of a gas within said airtight space; and a post-hardening step of heating the SAW device which has been subjected to the press molding step at a temperature and at a time at which the resin is completely hardened, wherein a thickness tr of the resin sheet before said lamination step satisfies: L /[( X+Gx )( Y+Gy )]≦ tr , where L =( X+Gx )( Y+Gy )( H+T+A )− XYT−XYA−[XVyA+YVxA +(4 VxVyA )/3], (L: a volume of the resin sheet necessary to seal the outer surface of one SAW chip, X: a length of one side of the SAW chip, Y: a length of the other side of the SAW chip, Gx: a distance between SAW chips adjacent in X direction, Vx: a distance from a dicing cutting margin extending in Y direction to a side surface of the proximate SAW chip, Gy: a distance between the SAW chips adjacent in Y direction, Vy: a distance from a dicing cutting margin extending in X direction to a side surface of the proximate SAW chip, H: a thickness of the resin located on the upper surface of one SAW chip after the outer surface of one SAW chip is completed in being covered with the resin sheet, T: a thickness of the piezoelectric substrate, and A: a distance from an upper surface of a mounting substrate base material to a bottom of the piezoelectric substrate).