Method for encapsulating electronic components or assemblies using a thermoplastic encapsulant

• US 5,106,785 A
• Filed: 01/16/1990
• Issued: 04/21/1992
• Est. Priority Date: 01/16/1989
• Status: Expired due to Fees

• Current Assignee: Epcos AG (TDK Corporation)
• Original Assignee: Siemens AG
• Inventors: Horsmann, Karl-Heinz, Scheffler, Horst, Bednarz, Juergen, Criens, Ralf, Peltz, Hanns-Heinz, Rauchmaul, Siegfried, Schmidt, Hans-Fr.
• Primary Examiner(s): Chaudhuri, Olik
• Assistant Examiner(s): Graybill, David E.
• Application Number:
  US07/464,934
• Time in Patent Office: 826 Days
• Field of Search: 437/215, 437/217, 437/219, 437/220, 437/214, 357/80, 357/74
• US Class Current: 29/856
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01004 Beryllium [Be]
• CPC Class Codes: H01L 2924/01019 Potassium [K]
• CPC Class Codes: H01L 2924/01068 Erbium [Er]
• CPC Class Codes: H01L 2924/3025 Electromagnetic shielding
• CPC Class Codes: H05K 5/0091 Housing specially adapted for small components for resistors H01C; for capacitors H01G; for integrated circuits H01L23/00
• CPC Class Codes: Y10T 29/49172 by molding of insulating material

Abstract

A component or assembly is accommodated in a housing formed of at least two joined housing parts. Terminal legs are conducted toward the outside of the housing. In order to enhance a sealing effect, and thus for protection against internal corrosion, an outside encapsulation of a thermoplastic plastic is applied to the housing by injection molding at least in the region of the joints of the housing and in the exit region of the terminal legs. Particularly given the hermetically tight encapsulation of surface-wave filters, encircling sections having a low wall thickness are provided on the housing parts in their peripheral regions, these sections being fused to the outside encapsulation.

Claims

1. A method for encapsulating an electronic component or assembly, comprising the steps of:

providing a component or assembly;

providing a housing formed of at least two pre-formed thermoplastic plastic housing parts which can be joined together at a joint and with the electronic component or assembly being completely enclosed within the housing, terminal legs extending from within the housing to an outside of the housing, the terminal legs exiting from the housing at an exit region; and

applying to both parts of the housing in a single injection molding step an outside encapsulation of a thermoplastic plastic by injection molding at least at said joint and at said exit region of the terminal legs.

2. A method for encapsulating an electronic component or assembly, comprising the steps of:

providing a housing formed of at least two pre-formed thermoplastic plastic housing parts which can be joined together at a joint;

providing terminal legs mounted to at least one of the housing parts such that when the housing parts are joined together the terminal legs extend from within the housing to an outside of the housing through a peripheral wall thereof;

placing in one of the housing parts a component or assembly which is electrically connected to inner ends of the terminal legs; and

assembling the at least two pre-formed housing parts, and thereafter in a single injection molding step, applying to both parts of the housing an outside encapsulation of a thermoplastic by injection molding at least at said joint and where said terminal legs exit from the peripheral walls so as to directly secure the at least two housing parts together.

3. A method for encapsulating an electronic component or assembly, comprising steps of:

providing a component or assembly;

manufacturing a pre-formed lower housing part of a thermoplastic plastic by injection molding and providing terminal legs thereat which are at least partially extrusion-coated at a passage region leading to an exit region when injection molding the lower housing part;

manufacturing a pre-formed upper housing part;

providing a housing formed of the lower housing part and the upper housing part which are joined together at a joint and with the electronic component or assembly being completely enclosed within the housing, said terminal legs extending from within the housing to an outside of the housing, said terminal legs exiting from the housing at said exit region; and

applying to both parts of the housing in a single injection molding step an outside encapsulation of a thermoplastic plastic by injection molding at least at said joint and at said exit region of the terminal legs.

4. A method according to claim 3 wherein after the injection molding of the lower housing part, anchoring the component or assembly to a floor of the lower housing part;

and connecting inner ends of the terminal legs to respective terminals of the component or assembly in electrically conductive fashion.

5. A method for encapsulating an electronic component or assembly, comprising the steps of:

providing a component or assembly;

manufacturing a pre-formed lower housing part and a pre-formed middle housing part of a thermoplastic plastic by injection molding, and completely extrusion-coating all around terminal legs in a passage region leading to an exit region when injection molding the middle housing part;

manufacturing a pre-formed upper housing part;

providing a housing formed of the lower housing part, middle housing part, and upper housing part which are joined together at respective joints and with the electronic component or assembly being completely enclosed within the housing, said terminal legs extending from within the housing to an outside of the housing, said terminal legs exiting from the housing at said exit region; and

applying to the lower, middle, and upper housing parts of the housing in a single injection molding step an outside encapsulation of a thermoplastic plastic by injection molding at least at said joints and at said exit region of the terminal legs.

6. A method according to claim 5 including the steps of anchoring the component or assembly to a floor of said lower housing part;

joining the middle housing part and the lower housing part; and

connecting inner ends of the terminal legs in electrically conductive fashion to allocated terminals of the component or assembly.

7. A method for encapsulating an electronic component or assembly, comprising the steps of:

providing a component or assembly;

providing a system carrier formed of an island, an island web, and terminal legs;

securing the component or assembly on the island;

applying by injection molding a pre-formed lower housing part of a thermoplastic plastic to an underside of the system carrier;

connecting inner ends of the terminal legs to respective terminals of the component or assembly in electrically conductive fashion;

providing an upper housing part;

providing a housing formed of the lower and upper housing parts which are joined together at a joint and with the electronic component or assembly being completely enclosed within the housing, said terminal legs extending from within the housing to an outside of the housing, the terminal legs exiting from the housing at an exit region; and

applying to the upper and lower housing parts of the housing in a single injection molding step an outside encapsulation of a thermoplastic plastic by injection molding at least at said joint and at said exit region of the terminal legs.

8. A method according to claim 7 including the step of applying an adhesion promoter on the system carrier in a passage region of the terminal legs leading to the exit region.

9. A method according to claim 7 including the step of partially filling interspaces between the terminal legs with thermoplastic plastic when applying the lower housing part to the system carrier.

10. A method according to claim 7 including the step of anchoring the island web in the thermoplastic plastic when applying the lower housing part to the system carrier.

11. A method for encapsulating an electronic component or assembly, comprising the steps of:

providing a component or assembly;

providing a housing formed of at least two pre-formed housing parts which can be joined together at a joint and with the electronic component or assembly being completely enclosed within the housing, terminal legs extending from within the housing to an outside of the housing, the terminal legs exiting from the housing at an exit region, and peripherally encircling outwardly protruding sections being provided on each of the two housing parts; and

applying to both parts of the housing in a single injection molding step an outside encapsulation of a thermoplastic plastic by injection molding at least at said joint and at said exit region of the terminal legs, and bonding the encircling sections to the outside encapsulation by choosing an injection temperature of the encapsulation and a meeting temperature of the encircling sections such that the encircling sections are partially melted by the plastic compound, said encircling sections providing a fused connection with the outside encapsulation during cooling.