DE102012204630A1 - Control device for controlling thermoplastic molding, during manufacturing of e.g. chip, has substrate and electronic component enclosed by mold where device is surrounded by cover over sealing region that is overlapped in exposed region - Google Patents

Abstract

The device (10) has a printed circuit board substrate (12) for accommodating an electrical or electronic component (16). The printed circuit board substrate and the electronic component are enclosed by a casting mold (18) that is surrounded by a thermoplastic cover (22). The control device is surrounded by the thermoplastic cover over a sealing region that is overlapped in a moisture exposed region. The thermoplastic cover is made of thermoplastic material containing globular filling i.e. anisotropic filler, in fiber or ball form, metal oxides and PA-GB50. An independent claim is also included for a method for manufacturing a control device.

Description

State of the art

DE 10 2009 027 905 A1 relates to a device with a semiconductor device and a housing and a method for manufacturing the device. The housing comprises at least one electrical connection and at least one attachment point. The housing has a first thermoset cladding which substantially encloses the semiconductor device. The housing further includes a second enclosure enclosing the first enclosure. The second envelope is made of a thermoplastic or of a thermosetting plastic. The electrical connection and the attachment point are located on the second enclosure.

DE 1096 25 228 C2 refers to a system carrier for mounting an integrated circuit in an injection molded housing. The system carrier has at least one conductor, which has a contact surface for contacting the integrated circuit from outside the housing. The shape of at least one of the conductors is designed such that a spring element is formed which can be compressed by an injection molding tool during injection molding of the housing. As a result, the contact surface can be pressed against an inner wall of the injection tool.

DE 10 2008 003 700 A1 has an electronic component and a method for its production to the object. The electronic component comprises electrically conductive contacts and a printed circuit board. The printed circuit board is covered by a jacket made of a first plastic material. The electrically conductive contacts are enveloped by a frame of a second plastic. The first plastic is a duroplastic, the second a thermoplastic. The thermoplastic does not present a barrier to gear oil, it serves to shape the thermoset, a pre-positioning of the electrically conductive contacts and serves to avoid the mechanical post-processing of the thermoset.

DE 10 2009 047 329 A1 has the subject of a flexible printed circuit board and an electrical device. The flexible printed circuit board has at least one printed conductor and a casing enclosing the printed conductor at least in certain areas. Between the conductor track and the sheath is at least one adhesive layer for fastening the sheath. It is provided that a cover at least partially partially covering is provided, wherein between the shell and the cover at least one filling layer is provided.

US 2006/0134937 A1 refers to an electronic component and a method for its production. According to this solution, an electronic component is covered by a lot of potted resin. It is given a convex connecting element, which has a metallic connection for contacting and which protrudes from the molded resin composition. Furthermore, a sealing element is arranged around the resin-coated mass.

It has been found that printed circuit boards or circuit boards, which receive electronic components and are subsequently encapsulated with a thermoplastic material, can be damaged by the stresses occurring in the injection molding process with regard to a thermal load and with regard to a pressurization. Furthermore, different thermal expansion coefficients of thermoplastics and circuit boards (circuit carriers) can cause damage to the electronic components in the application.

With a standard overmolding method, i. the standard applied Mold technology, which is usually used for the production of electronic components such as IC's, chips and the like, there is no way to produce complex geometries process reliable. As a result, the design options are limited.

Disclosure of the invention

The invention is based on a sheathing of the electronic components with a protective compound, which reduces thermal and mechanical stresses on the components of a thermoplastic encapsulation process. As protective compounds that are in question, materials such as elastomers (silicone rubber) or resins are conceivable. These protective compounds are able to ensure sufficient thermal and mechanical protection against damage to the electronic components when carrying out the thermoplastic encapsulation. In addition, negative effects of different coefficients of thermal expansion at temperature load in the application are excluded here. Although these requirements can be met by the standard mold process used so far, damage to the electronic components can not be completely eliminated by the injection molding process.

This is where the solution proposed by the invention starts.

Starting from the standard MOLD technology thermoplastic plastic materials are used in the context of this process considerably reduce the risk of damage to the electronic components to be encased.

It is to be ensured in the proposed solution according to the invention to keep the mold geometry as simple as possible in order in a second process step, the already ummoldete part, i. To coat the circuit carrier with electronic components with a thermoplastic such as PA. In this case, a protective material comprising thermoplastic properties is to be used with a globular filling such as, for example, PA-GB50. As a result, an isotropic behavior of the thermoplastic is ensured; Here a nearly identical temperature expansion behavior is achieved with regard to the thermally induced expansion of printed circuit board and protective ground. Alternatively, it is possible to use anisotropic fillers for critical spatial directions.

The thermoplastic shell is said to be the controller, i. externally enclose the printed circuit board with electronic components accommodated therein beyond a sealing area, so that the penetration of liquid media can certainly be ruled out. In this way, a possible gap formation between the mold body and the thermoplastic shell is unproblematic. Excessive loading of the mold body, however, due to different thermal expansions can be compensated by the structural design of the mold body. For example, beveled surfaces may be formed on the mold body.

Furthermore, it is possible to use fillers, for example metal oxides, which have good heat conduction properties. Thus, the thermoplastic sheath of the control unit is the same to a heat sink. It is possible to perform a simple surface structure in the form of cooling fins in great simplicity.

Advantages of the invention

By the proposed solution according to the invention, a weight and cost savings can be achieved in that the molding compound used is reduced and the molecular weight used per control unit is reduced, larger control units can ummoldet.

The inventively proposed solution of the encapsulation of a printed circuit board or a circuit substrate are added to the electronic components, also allows complex mechanically resilient geometries to delineate filigree. Complex, mechanically loadable geometries are, for example, the locking of a cable harness connector, guide ribs, C-rail. Optionally, it is possible to directly inject a plug interface and thus avoid an exposed seal. In a plug-in interface designed as an encapsulation, the tolerance chain can be reduced by a direct relationship between the printed circuit board and the housing. Furthermore, by fasteners between the controller, i. the provided with at least one electronic component circuit board and the body of a vehicle are molded directly. It is possible to form a process-reliable filling of filigree geometries by injection molding. In the method proposed according to the invention, a process-reliable filling of even filigree geometries by the injection molding technique is possible, since a good flow properties protective compound, namely a thermoplastic is used. The tooling possibilities of the injection molding technology can be fully exploited due to the presence of low draft angles and the use of sliders. There is an easier sealability of the geometry in the injection molding tool, since the thermoplastic has a higher viscosity compared to the molding compound in the processing. Optionally, there is improved heat removal from the tool by appropriately filled thermoplastics. The printed circuit board positioning holes used as standard today are securely sealed by the thermoplastic used as a protective compound so that the ingress of moisture can be excluded. There is a much higher robustness of the circuit board against damage.

Brief description of the drawings

With reference to the drawing, the invention will be described below in more detail.

It shows:

1 a control unit with a mold core surrounding by a thermoplastic sheath,

2 a top view of the provided with a thermoplastic clad control unit,

3 the representation of a sealing area and a wet area by means of a harness connector and a control unit,

4 an alternative embodiment of the thermoplastic casing with molded-on interface collar,

5 a top view of the in 4 illustrated further embodiment of the present invention proposed control unit with thermoplastic sheath,

6 a surrounded by a thermoplastic sheath Mold core with right-angled end faces and

6.1 a representation of a surrounded by the thermoplastic sheath mold body, which has a relative movement between mold core and thermoplastic sheath enabling inclinations for stress compensation.

Embodiments of the invention

1 shows a controller with a Moldkern, which is surrounded by a thermoplastic sheath.

From the illustration according to 1 goes a control unit 10 which is a printed circuit board substrate 12 (PCB). The printed circuit board substrate 12 includes tabs on an exposed end 14 , which are also referred to as Lands and which, as shown in the illustration 1 shown at the top and bottom of the free from the control unit 10 protruding end of the printed circuit board substrate 12 lie. However, there is also the possibility of the contact flags 14 either only on the top or only on the underside of the freely projecting end of the printed circuit board substrate 12 provided. On the printed circuit board substrate 12 can on top and / or bottom electrical or electronic components 16 be arranged. Im in 1 illustrated embodiment, the electronic components are located both at the top and at the bottom of the printed circuit board substrate 12 , The electronic components 16 including the printed circuit board substrate 12 are from a mold core 18 enclosed, which is usually made of a thermoset, such as epoxy (polyaddition product).

The moldings 18 , which the electrical or the electronic components 16 at the top and bottom of the printed circuit board substrate 12 in turn, is of a thermoplastic cladding 22 surround. In the thermoplastic sheath is a radial seal 20 let in, which is a sealing area 36 from a moisture-exposed area 38 separates (see illustration according to 3 ).

The thermoplastic cladding 22 the solution proposed according to the invention is subsequently produced from a thermoplastic containing a globular or fibrous filling. The globular filling may be, for example, PA-GB50 which imparts isotropic properties to the thermoplastic. The material of the thermoplastic is preferably one which has a temperature expansion behavior or has a corresponding coefficient of thermal expansion which corresponds to that of the printed circuit board substrate 12 of the control unit 10 corresponds or which is very similar to this. Furthermore, the thermoplastic material from which the thermoplastic sheath can be made 22 injected, anisotropic properties be added to fillers, which are relevant for critical spatial directions.

The fillers used are mineral fillers, for example short or long glass fibers, carbon fibers, aramid fibers. The critical spatial directions are those directions in which relative movements between the mold core 18 and the thermoplastic cladding 22 may occur.

As in 1 is further indicated, the thermoplastic sheath 22 of the mold core 18 also a ribbing 24 exhibit. This is useful, for example, if the thermoplastic material is mixed with metal oxides which have good heat conduction properties. This is how the thermoplastic sheath can be 22 of the mold core 18 as a heat sink, on which a corresponding increase in surface area, for example by the in 1 shown ribbing 24 can be injected. Without additional work steps would be required, the ribbing enabling a heat dissipation 24 during the injection process of the thermoplastic envelope 22 be generated.

The representation according to 1 it can also be seen that on an outer surface 28 the thermoplastic cladding 22 a fastener 26 located. This can also be very easy in the production of the thermoplastic envelope 22 for example, as locking cams 46 trained, be manufactured without the need for additional operations.

The representation according to 2 is a plan view of the thermoplastic enclosure of the control unit 10 as shown in FIG 1 refer to.

From the plan view it is apparent that the printed circuit board substrate 12 at its free from the thermoplastic cladding 22 protruding end on top the tabs 14 (Lands). In the 2 protrudes laterally over the thermoplastic sheath 22 the radial seal 20 out. On top of the thermoplastic sheath 22 are mutually parallel single ribs of the ribbing 24 . 30 refer to. The representation according to 2 , Reference number 32 shows a partial Moldung 32 , The mold can also be designed to extend on both sides, cf. reference numeral 34 in 1 which means that the moldkernel 18 the printed circuit board substrate 12 - as in 1 shown - evenly encloses at the top and bottom.

3 shows the representation of a sealing area and a wet area using a directly contacting harness connector and a control unit with mold core and thermoplastic sheath.

3 shows that the controller 10 at the open end of the printed circuit board substrate 12 , where the tabs are 14 are arranged through a harness connector 40 is contacted. At the harness connector 40 as shown in 3 it is a directly contacting harness connector 40 , The harness connector 40 encloses the contact 42 and has an insertion opening 44 on what parts of the cladding 22 of thermoplastic material still encloses. Inside the slot 44 There is a boundary between a sealing area 36 and a moisture-exposed area 38 , Along the border between the two mentioned areas 36 and 38 seals the radial seal 20 the inside of the insertion opening 44 against the thermoplastic sheath 22 from. A locking of the control unit 10 in the harness connector 40 done by the here as locking cam 46 trained fastener. As shown in the illustration 3 As can be seen, the thermoplastic sheath extends 22 completely within the moisture exposed area 38 and beyond partially also in the sealing area 36 into it. By such a configuration of the thermoplastic sheath 22 is the control unit 10 externally to above the sealing area 36 enclosed, so that the penetration of liquid media can be excluded with certainty. From the illustration according to 3 In addition, it emerges that the printed circuit board substrate 12 with the recorded electronic or electrical components 16 completely from the mold core 18 - usually designed as thermoset - is enclosed. Around the mold core 18 around is the thermoplastic cladding 22 running, lying here at the top, the ribbing 24 for better heat dissipation to the environment. The moisture that is on the outside 28 the thermoplastic cladding 22 located and the the control unit 10 thus exposed, can not over the insertion opening 44 into the harness connector 40 to crawl, as this is due to the radial seal 20 is prevented. By the selected arrangement according to 3 can be achieved that a potential gap formation between the mold core 18 and the inside of the thermoplastic wrapper 22 remains problematic, since in any auftuende column moisture is unable to penetrate.

4 shows a further possibility of execution of the inventively proposed control device, the mold core is surrounded by the thermoplastic sheath.

In this embodiment is located on the plug contact side of the thermoplastic envelope 22 a plug connector 52 , This encloses the contact lugs 14 at the end of the printed circuit board substrate to be contacted 12 , Advantageously, to the thermoplastic sheath 22 in this embodiment interface collar 28 ( 48 ??). As seen from the top view 5 on the in 4 in the side view shown second embodiment of the present invention proposed control unit 10 As can be seen, each includes the interface collar 48 a passage opening 50 , 5 moreover, shows that the male connector part 52 or the in 5 shown underside extends such that the tabs 14 at the end of the printed circuit board substrate to be contacted 12 are covered. At the connector opposite part 52 can be analogous to in 3 Locking cam shown 46 on the outside of the thermoplastic sheath 22 be provided corresponding fasteners. The top view according 5 shows that the thermoplastic sheath 22 in this embodiment, four interface collar 48 comprising, with which the thermoplastic sheath 22 and thus the control unit 10 can be fixed at an installation location. Instead of in the 4 and 5 shown two or four interface collar 48 can also have a different number of interface collars 48 in the production of the thermoplastic casing 22 be executed.

The representation according to 6 shows a variant embodiment according to which a mold core has a rather unfavorable geometry; in the 6 embodiment shown is not part of the invention, but is included for explanatory purposes.

To clarify the description below 6.1 is related to 6 pointed out that in this embodiment of the mold core 18 has a substantially rectangular geometry. A distance between one of the thermoplastic sheath 22 surrounded area of the end of the printed circuit board substrate 12 up to a first end face 56 is by reference numerals 60 designated. Both mentioned first front page 56 as well as another second face 58 of the mold core 18 as shown in 6 are formed at right angles. 6 further shows that in this geometry choice of Moldkerns 18 the molds 18 surrounding thermoplastic cladding 22 has a comparatively small thickness. Due to the selected geometries, different thermal expansion coefficients can lead to stresses between the mold core 18 that the electrical or electronic components 16 on the PCB substrate 12 encloses and surrounding this thermoplastic cladding 22 come. Due to the small thickness of the thermoplastic sheath 22 especially in the area of the end faces 56 . 58 of the mold core 18 is also a crack in the thermoplastic sheath - appropriate temperature changes - not excluded. At the end of the printed circuit board substrate to be contacted 12 are located on the top and bottom of the same the already mentioned contact lugs 14 ; Furthermore, the thermoplastic sheath 22 the radial seal 20 on. At the top of the thermoplastic cladding 22 there is the ribs favors a heat dissipation 24 ,

In the illustration according to 6.1 has the moldkern 18 - Compared with the rectangular geometry of the mold core 18 as shown in 6 - A much cheaper outer geometry. In particular, compared with the rectangular geometry of the mold core 18 according to 6 at the mold core 18 according to 6.1 bevel 62 . 64 formed in different pitch. The slopes 62 . 64 at the opposite ends of the mold core 18 Run substantially in the horizontal direction and as shown in the illustration 6 shows that the front ends 56 respectively 58 of there a rectangular geometry having mold core 18 extend substantially in the vertical direction. The orientation of the front sides 56 respectively 58 the variant in 6 are rather unfavorable for stress relief with different coefficients of expansion of the juxtaposed materials, while the bevels 62 . 64 , which according to the variant in 6.1 extend substantially in the horizontal direction, relative movements between the outside of the mold core 18 on the one hand and on the other hand, the wrapping of thermoplastic material 22 enable. Due to the possible relative movements between the mold core 18 or its slopes 62 and 64 and the inside of the thermoplastic wrapper 22 a voltage reduction can take place. The more similar the thermal expansion coefficients of the material from which the thermoplastic sheath 22 is made of the material and which the Moldkern 18 represents, the lesser need for relative movements for stress relief can be achieved between said components.

In 6.1 is shown, cf. position 68 . 70 , like the thickness of the mold core 18 on the one hand and the corresponding course of thickness 70 the thermoplastic cladding 22 on the other hand runs. Starting from the radial seal 20 causes a gentle rise of the slopes 62 at this end of the mold core 18 a corresponding reduction in the thickness of the thermoplastic sheath 22 , At the opposite end of the printed circuit board substrate 12 in which there is an overlap 66 of the printed circuit board substrate 12 and the mold core 18 - in contrast to 6 - comes, run the second slopes 64 in different gradients. Corresponding to these differently shaped slopes of the second slopes 64 , the thickness curve turns 70 the thermoplastic cladding 22 at this end of the thermoplastic sheath 22 one. The first and second slopes 62 respectively 64 reduce stresses between the mold core 18 and the thermoplastic cladding 22 , which are caused by different thermal expansion coefficients, as the thermoplastic sheath 22 in limits relative to the mold 18 can move.

The invention also relates to a method for producing the control unit 10 , First, the sheath of the printed circuit board substrate 12 and at least one electrical or electronic component received thereon 16 with a mold body 18 , The material of the mold body 18 ie, a protective compound which covers and protects the at least one electrical and electronic component reduces mechanical and thermal stresses on the components 16 act when involved in the production of the mold core 18 a Umspritzungsvorgang connects. According to the invention, this takes place on the production of the mold core 18 subsequent encapsulation process with a thermoplastic material comprising a globular filling, for example PA-GB50, such that the thermoplastic material behaves isotropically. The thermoplastic material of the moldings 18 surrounding thermoplastic encapsulation 22 has a similar temperature expansion behavior as the printed circuit board substrate 12 , Alternatively, it is possible to add anisotropic fillers to the thermoplastic material which have a particular relevance for the critical spatial directions X, Y and Z direction.

For the protective compound, ie the material of the mold core 18 These are, for example, elastomers such as silicone rubber or resins. In the production of the thermoplastic casing 22 of the mold core 18 is to take care that the geometry of the mold core 18 is kept as simple as possible and in particular too high a load at high thermal loads by appropriate provision of slopes 62 . 64 on the mold body 18 can be avoided.

By the method proposed according to the invention filigranere structures can be produced in comparison to the standard gold process, in particular there is the possibility of a plug-contrary 52 over which the control unit 10 is electrically contacted to lock. Furthermore, through the radial seal 20 the plug opposite 52 to the housing of the control unit 10 sealed off; the control unit 10 can be like in 5 shown with interface collar 48 be equipped for connection to a vehicle. Also, the provision of ribbing 24 in one operation is possible. From stand-technical reasons, standard bullion compounds used for ICs, processors or memory modules that were previously used in standard gold methods are not able to reproduce these complex geometries.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009027 A1 [0001]
• DE 109625228 C2 [0002]
• DE 102008003700 A1 [0003]
• DE 102009047329 A1 [0004]
• US 2006/0134937 A1 [0005]

Claims (12)

Control unit ( 10 ) with a printed circuit board substrate ( 12 ), to which at least one electrical or electronic component ( 16 ), wherein the printed circuit board substrate ( 12 ) and the at least one electronic component ( 16 ) of a mold core ( 18 ) and the mold core ( 18 ) of a further thermoplastic sheath ( 22 ), characterized in that the control unit ( 10 ) via a sealing area ( 36 ) in a moisture-exposed area ( 38 ) of the thermoplastic envelope ( 22 ) is surrounded. Control device according to claim 1, characterized in that the thermoplastic sheath ( 22 ) is made of a thermoplastic containing a globular filling. Control unit ( 10 ) according to the preceding claim, characterized in that the globular filling contains PA-GB50. Control unit ( 10 ) according to one of the preceding claims, characterized in that the thermoplastic has isotropic properties. Control unit ( 10 ) according to one of the preceding claims, characterized in that the thermoplastic contains anisotropic fillers, in fiber or ball form. Control unit ( 10 ) according to one of the preceding claims, characterized in that the thermoplastic contains metal oxides. Control unit ( 10 ) according to one of the preceding claims, characterized in that the thermoplastic sheath ( 22 ) one or more molded-on interface collars ( 48 ). Control unit ( 10 ) according to one of the preceding claims, characterized in that the thermal expansion coefficients of the material of the printed circuit board substrate ( 12 ) and the thermoplastic material of the envelope ( 22 ) correspond to each other or at least are similar. Control unit ( 10 ) according to one of the preceding claims, characterized in that the mold core ( 18 ) of the control unit ( 10 ) Bevels ( 62 . 64 ), along which a relative movement between the mold core ( 18 ) and the thermoplastic envelope ( 22 ) for voltage compensation. Method for producing a control unit ( 10 ) according to one or more of claims 1 to 9 with the following method steps: a) encasing a printed circuit board substrate ( 12 ) and at least one electronic component ( 16 ) with a mold core ( 18 ), the loads of the at least one electronic component ( 16 ) is reduced during a subsequent encapsulation process, b) encapsulation of the mold core obtained according to process step a) (US Pat. 18 ) with a thermoplastic material to form a sheath ( 22 ), c) production of the coating ( 22 ) of the mold core ( 18 ) such that they extend over a sealing area ( 36 ) of the control unit ( 10 ) extends. A method according to claim 10, characterized in that according to method step b) are added to the thermoplastic material metal oxides. Method according to claim 11, characterized in that on an outer surface ( 28 ) of the thermoplastic envelope ( 22 ) a ribbing ( 24 ) is injected.

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