Method of molding resin for sealing an electronic device
AssigneeTowa Corporation
InventorsMichio Osada, Yoshihisa Kawamoto
Life of this patent
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Abstract
In a method for molding resin to seal an electronic part, a sealed space portion is formed between molding surfaces of an upper mold section and a lower mold section by covering an outer side periphery of a pot, a resin path and a cavity. A resin tablet is heated at its bottom portion and peripheral portion in the pot of the lower mold section to expand upwardly from its top portion. Air and moisture included inside the resin tablet is expelled into the sealed space portion which is evacuated including any air and moisture inside the sealed space portion, whereby the formation of voids in the molded resin body is avoided.
Claims12
A method for sealing an electronic part by molding resin around said electronic part, in a mold having an upper mold section and a lower mold section to enclose a mold cavity, at least one resin melting pot, means for pressurizing a resin tablet in said resin melting pot, a resin flow path from said resin melting pot to said mold cavity, and a gas exhaust path from said resin melting pot through said mold cavity to an evacuation pump, comprising the following steps:
- (a) placing an unpreheated resin tablet having room temperature into said resin melting pot and placing said electronic part into said mold cavity, whereby preheating said resin tablet outside said pot is avoided,
- (b) preheating said resin tablet directly in said resin melting pot,
- (c) sealing said upper and lower mold sections relative to each other for excluding outside air from a sealed space including at least said resin melting pot, said mold cavity, and said resin flow path,
- (d) further heating said resin tablet in said resin melting pot for expanding said resin tablet to freely release air and moisture from said resin tablet in said resin melting pot while said outside air exclusion is maintained by said sealing step,
- (e) completely clamping closed said upper and lower mold sections to each other while maintaining said sealing step,
- (f) evacuating said sealed space while maintaining said exclusion of outside air, and
- (g) applying pressure to said resin tablet in said resin melting pot for forcing melted resin into said mold cavity around said electronic part while continuing said evacuating step at least partly during said pressure applying, whereby air and moisture are evacuated.
A method for sealing an electronic part by molding resin around said electronic part, comprising the following steps:
- (a) placing an unpreheated resin tablet having room temperature into a pot of a mold and placing said electronic part into a mold cavity of said mold and closing said mold, whereby preheating said resin tablet outside said pot is avoided,
- (b) forming a sealed space between first and second sections of said mold, said sealed space including a gap between facing mold plane surfaces of said first and second mold sections, prior to completely closing said mold by moving said facing mold plane surfaces into contact with each other, and further comprising evacuating said gap,
- (c) heating said tablet from room temperature directly in said pot for expanding and melting said tablet in said pot while simultaneously evacuating said mold, whereby an evacuating flow removes air and moisture from said mold including air and moisture liberated from inside said resin tablet by said heating of said resin tablet, and
- (d) continuing said evacuating while pressurizing melted resin for injecting said melted resin into said mold cavity, and then curing said resin for encapsulating said electronic part in said mold.
Dependencies are inferred from the claim text.