WO2016177629A1 - Electronic component and method for the production thereof - Google Patents

Abstract

The invention relates to a method for producing an electronic component (E), wherein a PCB (1) is connected to a carrier body (3), the PCB (1) is populated with a plurality of electronic components (2) and the PCB (1) has at least one cover element (5) which covers at least partially the plurality of electronic components (2) on the PCB (1). According to the invention, the at least one cover element (5) is connected to the PCB (1) via a thermoplastic intermediate element (6). The invention further relates to an electronic component (E) produced according to such a method.

Description

description

The invention relates to a method for producing an electronic component according to the preamble of claim 1. The invention further relates to an electronic component produced by such a method. Electronic components in the form of integrated circuits usually comprise electronic assemblies, which are brought together on a printed circuit board to an electrical circuit arrangement. Such electronic components are used for example in control units for motor vehicles, eg. B. in transmission control units used.

To produce such an electronic component, the printed circuit board, for example, on a metallic support, for. As an aluminum support, laminated. During lamination, adhesive compounds are produced by pressure and / or temperature.

The modules on the circuit board may take the form of so-called "bare die" or as a soldered electronic components with a plastic cover on the flat side of the printed circuit board to ^¬ arranged. As can be "bare die" refers to integrated electronic components, which are further processed without a cover. These electronic assemblies are applied directly to the circuit board and by means of electrical connection elements, such. As bonding wires, stamped grid, flexible films, etc., connected to other arranged on the circuit board electronic components or modules.

To protect against external influences, the electronic component by means of one or more housings against external influences, eg. As transmission oil, protected. The housing surrounds at least a portion of the populated flat side of the circuit board. The housing is advantageously formed from an electrically iso ^¬ lierenden material and is connected to the printed circuit board for example by means of frictional and form closure, z. B. the housing is riveted or screwed to the circuit board.

Is a material connection of the housing to the Lei terplatte ^¬ required, in addition to ensuring a tightness and a temperature and pressure entry on the electronic components on the circuit board to be considered. If the housing is laminated to the printed circuit board, for example, temperatures of up to 200.degree. C. may occur during the laminating process and, if necessary, postcuring steps may be necessary which cause further temperature effects, for example

Post curing in a period of three hours at a temperature of 150 ° C in a convection oven.

Is used as an adhesive for the cohesive connection of the housing, a potting compound, for. For example, silicone rubber used, a thixotropic adhesive is additionally required because low molecular weight siloxanes can escape from the silicone rubber, resulting in leaks and / or detachment of the housing may result from the circuit board.

The invention is based on the object to provide an improved method for producing an electronic component and an improved electronic component.

With regard to the method, the object is achieved according to the invention with the features specified in claim 1. With regard to the electronic component, the object is achieved according to the invention with the features specified in claim 7.

Advantageous embodiments of the invention are the subject of the dependent claims.

In a method for producing an electronic component, is

a printed circuit board connected to a carrier body, - The printed circuit board equipped with a number of electronic components and

- Provided the circuit board with at least one cover, which covers the number of electronic components on the circuit board at least partially. According to the invention it is provided that the at least one cover is connected via a thermoplas ^¬ tical intermediate element with the circuit board.

By means of the method, it is possible to cover electronic components media-tight and thus protect against external influences. The thermoplastic intermediate member thereby protects the electronic component to be concealed from a temperature which acts on the environment during assembly of the cover. An embodiment of the invention provides that the thermoplastic intermediate element is laminated to a populated flat side of the printed circuit board.

The laminate composite between the printed circuit board and the thermoplastic intermediate element enables a media-tight and mechanically stable connection between these two components.

Furthermore, the circuit board with an unpopulated

Flat side, d. H. with a side facing away from the thermoplastic intermediate element flat side, laminated to the carrier body.

This makes it possible for the connection of the thermoplastic intermediate element to the printed circuit board to be produced simultaneously with the connection of the printed circuit board to the carrier body. Thus, costs and effort for the production of the electronic component can be optimized.

A further embodiment of the invention provides that, the at least one cover with the thermoplastic Zvi ^¬ rule element welded. Preferably, ultrasonic welding or laser welding is performed as the welding method. The thermoplastic Zvi ^¬ rule element is to, for example, of polyamide 6.6, which represents a low-temperature-stable thermoplastic material, which when exposed to high temperatures at least in regions on ^¬ melts and thereby joins a material fit with the circuit board. Is the area on the printed circuit board which is to be covered with a covering very large - in ^¬ play, a region with a plurality of electronic components which are combined to form an integrated circuit arrangement - can alternatively be a high-temperature-turstabiler thermoplastic such. As polyphthalamide, polyphenylene sulfide or polyethersulfone, be used as a material for the thermoplastic intermediate element. Thus, effects of different thermal expansion coefficients between the thermoplastic intermediate member and the circuit board can be reduced.

Furthermore, an embodiment of the invention provides that at least one electronic component to be covered is provided with an electrically insulating potting compound.

The potting compound consists for example of silicone rubber and forms after curing a positive and cohesive bond with the electronic component, so that it is additionally protected from external influences.

The invention further provides an electronic component which is produced by the method according to the invention. The electronic component comprises a circuit board having a number of electronic components, a carrier body, which is connected to the circuit board, and at least one covering element ^¬ which the number of electronic components on the circuit board at least partially obscured. The cover is connected via an intermediate element to the circuit board.

The electronic component is for arrangement in one

Control unit for a motor vehicle, for example in one Gearbox control unit, provided. The cover protects the number of electronic components from external influences, such. As chips, transmission oil. By means of the thermoplastic intermediate ^¬ elements while a media-tight, cohesive connection of the cover is possible on the circuit board, in the production of high temperatures act on the environment, such. B. welding.

An embodiment of the invention provides that the thermoplastic intermediate element at least partially encloses a region of the printed circuit board to be covered.

For example, the thermoplastic intermediate element is annular and encloses an electronic component on the circuit board. The cover is arranged on the open end of the thermoplastic intermediate element and connected thereto.

A further embodiment of the invention provides that the at least one cover element has at least one groove for receiving an adhesive.

The groove serves to receive an adhesive in the event that the cohesive connection between the cover and the thermoplastic intermediate element is damaged. By means of the adhesive, a repair of the cohesive connection is possible, so that, furthermore, a media-tight bond between the cover element and the thermoplastic intermediate element is si ^¬ chergestellt.

In addition, the circuit board may have a groove for receiving an adhesive so that the laminate bond between said thermoplastic intermediate element and the circuit board gege ^¬ appropriate, can be repaired.

In a further embodiment of the invention, the circuit board is mechanically flexible. The circuit board comprises at least one mechanically flexible section, which z. B. made of polyamide.

Embodiments of the invention are explained in more detail below with reference to drawings.

Show:

1 shows schematically a sectional view of an electronic component with a populated printed circuit board and a carrier body according to the prior art, and

2 shows schematically a sectional view of an inventive embodiment of an electronic component.

Corresponding parts are provided in all figures with the same reference numerals.

Figure 1 shows an electronic component E according to the prior art in a perspective view.

The electronic component E comprises a printed circuit board 1, which has a plurality of electronic components 2 on a flat side in the exemplary embodiment shown, as well as a carrier body 3.

The circuit board 1 is, for example, an HDI printed circuit board (HDI = High Density Interconnect) with a so-called Bere-Dies-Montage (Bare Dies = unhoused semiconductor components) for use as transmission control in a motor vehicle. The electronic component E is thus as a control unit, z. B. as a transmission control unit, can be used.

The printed circuit board 1 comprises as a substrate, for example, impregnated in epoxy resin glass fibers and is thus rigid. Alternatively, the circuit board 1 also mechanically flexible be formed and comprises at least one mechanically flexible portion which z. B. is made of polyamide, on the one or both sides conductor tracks for the electrical connection of the electronic components 2 are applied.

The printed circuit board 1 is further connected to another flat side, in this case a side remote from the electronic components 2 flat side, materially connected to the support body 3, z. B. by means of a laminate composite V. The laminate composite V here is an adhesive connection between the circuit board 1 and the carrier body 3, which is produced by means of pressure and optionally by means of temperature.

The carrier body 3, also referred to as a leadframe or (copper) stamped grid / carrier body, has an electrically conductive carrier structure. For example, the Trä ^¬ gerkörper 3 is formed of aluminum and is manufactured as a stamped grid, wherein the support body 3 contact pins (not shown) for electrically contacting the electronic components 2 has.

As electronic components 2, for example, speed sensors ^¬ and / or Hall sensors are arranged on the circuit board 1, which are provided in the present embodiment with a laminated plastic cover. Furthermore, a cover 5 is arranged on the circuit board 1, which is fastened by means of rivets frictionally to the circuit board 1. In addition, the cover 5 may be materially connected to the circuit board 1, z. B. by means of a solid material seal. 4

The cover 5 is used in particular to cover a number not shown in detail so-called bare Dies, which are glued or soldered to the flat side of the circuit board 1. An electrical contact between the Bare Dies and the

Printed circuit board 1, for example by means of Bonddrahtver ^¬ compounds. The cover 5 is to protect the electronic components 2 from external influences, such. As gear oil, chips, etc., formed from a mechanically and chemically resistant and electrically insulating material. For example, the cover element 5 is formed from a duroplastic material.

In the prior art, the cover member 5 is usually laminated on the circuit board 1. In particular, the printed circuit board 1 is laminated onto the carrier body 3. The laminate composite V is prepared by means of an adhesive, for. As acrylic adhesive, prepared, which produces a cohesive bond between the circuit board 1 and the carrier body 3 under the action of pressure and temperature. In this case, the printed circuit board 1 is still unpopulated in a first step and thus not provided with electronic components 2.

Subsequently, the circuit board 1 is equipped with a number or plurality of electronic components 2. For example, sensors and / or bare dies are glued or soldered to the printed circuit board 1 and electrically connected to the circuit board 1, z. B. by means of bonding wire connections and / or by means of solder joints. To protect unhoused electronic components 2, z. As sensors, the cover 5 is placed on the circuit board 1 on ^¬ , wherein alternatively also a plurality of cover 5 are conceivable. 1 shows the electronic component E after a second production step, in which the cover 5 is laminated to the circuit board 1. The laminate composite V between cover 5 and circuit board 1 is hereby similar to the first manufacturing step by means of an adhesive, for. As acrylic adhesive produced, which produces a cohesive bond between the circuit board 1 and the cover 5 under the action of pressure and temperature. During lamination temperatures up to 200 ° C can be reached. In addition, post-cure steps may be required to fully cure the adhesive. For example, a period for post-curing of up to three hours at a temperature of 150 ° C, z. B. in a convection oven, possible. Furthermore, usually no geometry for limiting the adhesive is provided on the circuit board 1. Is also provided, with the cover 5 to be hidden area, for. As an integrated circuit and / or their peripheral contacts such as bonding wires to provide in addition with a potting compound, a costly potting compound with thixotropic properties is required. This is because, for example, that with the use of Sili ^¬ konkautschuk as sealing compound low molecular weight siloxanes can escape during lamination. This leads to leaks and possibly to detachment of the cover 5 from the Lei ^¬ terplatte 1. A potting compound, however, makes sense, since this area of the circuit board 1 is protected from residual dirt and thus short circuits.

For a cost and expense-optimized production of the electronic component E, the electronic components 2 are reliably protected from external influences, the invention proposes a thermoplastic intermediate element 6, as described in the following Figure 2.

FIG. 2 shows a sectional view of an embodiment according to the invention of an electronic component E with a thermoplastic intermediate element 6.

In the present exemplary embodiment, the thermoplastic intermediate element 6 is of annular design and surrounds the electronic component 2 to be covered. Alternatively, other embodiments of the thermoplastic intermediate element 6 are also possible, with a media-tight closure of the electronic component 2 or the region to be covered closed circumferential course is advantageous. A height of the thermoplastic intermediate element 6 is expediently greater than a height of the electronic component 2 or region to be covered.

The thermoplastic intermediate element 6 is made of a low-temperature-stable thermoplastic, such as. B. Polyamid6.6, which melts at least partially when exposed to high temperatures and thereby materially connects to the circuit board 1. The thermoplastic Zwischenele ^¬ ment 6 is thus laminated to the circuit board 1.

If the area to be covered on the printed circuit board 1 is very large-for example, an area with an integrated circuit-the thermoplastic intermediate element 6 may alternatively also be made of a high-temperature-stable thermoplastic, such as, for example. As polyphthalamide, polyphenylene sulfide or polyethersulfone be formed. Thus, effects of different thermal expansion coefficients between the thermoplastic intermediate element 6 and the printed circuit board 1 can be reduced.

If a plurality of cover elements 5 are provided, a number of thermoplastic intermediate elements 6 is also conceivable, which corresponds to a number of cover elements 5.

The lamination of the thermoplastic intermediate element 6 is preferably laminated during the first production step by ^¬ feasible, in which the circuit board 1 to the carrier body. 3 Thus, the production of the electronic component E can be time and cost optimized. In addition, the required in the prior art solid seal 4 can be omitted.

FIG. 2 shows the electronic component E in an exploded view with cover element 5 not yet fastened for better illustration of the shape and configuration of the thermoplastic intermediate element 6 before attachment of the cover element 5 to the printed circuit board 1, but after attachment to the Circuit board 1. For fastening and sealing the connection between the cover 5 and circuit board 1, the cover 5 is welded to the thermoplastic intermediate element 6. For welding the cover 5 with the thermoplastic intermediate element 6, for example, ultrasonic welding ^¬ or laser welding is.

By means of the thermoplastic intermediate element 6 is thus a media-tight closure of a region on the circuit board 1 is possible, which is long-term mechanically reliable and stable. In addition, by means of the thermoplastic intermediate element 6, the use of a low-cost potting or sealing compound, such. As silicone rubber, for additional protection against residual dirt before attachment of the cover 5 possible. The silicone rubber or silgel is very liquid in the uncured state. The intermediate element 6, in particular its U-shaped cross section, acts like a frame, so that the silicone rubber or the silicone gel can not leak and is held in its intended position.

In one possible embodiment of the invention, the intermediate element 6 and / or the cover element 5 additionally has at least one groove for receiving an adhesive. In the embodiment shown, the intermediate element 6 has such a receiving groove N.

The groove serves to receive the adhesive in the event that the welded joint between the cover 5 and the thermoplastic intermediate element 6 is damaged. By means of the adhesive repair is possible, so that the elec ^¬ ronic component 2 or the area of the circuit board 1 is still closed media-tight.

Additionally or alternatively, the circuit board 1 may have a groove for receiving an adhesive, so that the laminate natverbund V between the thermoplastic intermediate element 6 and the circuit board 1 can also be repaired.

Reference sign list

1 circuit board

 2 electronic component

 3 carrier body

 4 solid seal

 5 cover element

 6 thermoplastic intermediate element

E electronic component

 N recording groove

 V laminate composite

Claims

claims 1. A method for producing an electronic component (E), wherein a printed circuit board (1) is connected to a carrier body (3), - The printed circuit board (1) with a number of electronic ^{components ¬} (2) is fitted and  the printed circuit board (1) is provided with at least one covering element (5) which at least partially covers the number of electronic components (2) on the printed circuit board (1), characterized in that the at least one Abdeckele ^¬ ment (5) via a thermoplastic intermediate element (6) with the circuit board (1) is connected. 2. The method according to claim 1, characterized in that the thermoplastic intermediate ^¬ element (6) on a populated flat side of the printed circuit board (1) is laminated. 3. The method according to claim 1 or 2, characterized in that the printed circuit board (1) with an unpopulated flat side on the support body (3) is laminated. 4. The method according to claim 3, characterized in that the lamination of the thermoplas ^¬ tables intermediate element (6) on the printed circuit board (1) and laminating the circuit board (1) on the support body (3) is carried out simultaneously. 5. The method according to any one of the preceding claims, characterized in that the at least one Abdeckele ^¬ ment (5) with the thermoplastic intermediate ^element (6) ver ^¬ welded. 6. The method according to any one of the preceding claims, characterized in that at least one to be covered electronic component (2) is provided with an electrically insulating potting compound. 7. Electronic component (E) prepared by a method according to any one of the preceding claims comprising a printed circuit board (1) with a number of electronic ^components (2),  - One with the circuit board (1) connected to the carrier body (3), and - At least one cover (5), which at least partially covers the number of electronic components (2) on the circuit board (1), wherein the at least one cover (5) via a thermoplastic intermediate element (6) with the Lei ^¬ terplatte (1) is. 8. Electronic component (E) according to claim 7, characterized in that the thermoplastic intermediate ^¬ element (6) enclosing a portion of the printed circuit board (1) to be covered. 9. Electronic component (E) according to claim 7 or 8, characterized in that the at least one Abdeckele ^¬ ment (5) and / or the intermediate element (6) has at least one receiving groove (N) for receiving an adhesive. 10. Electronic component (E) according to one of claims 7 to 9, characterized in that the printed circuit board (1) is mechanically flexible.