WO2019001810A1

WO2019001810A1 - Electronic module and method for producing an electronic module

Info

Publication number: WO2019001810A1
Application number: PCT/EP2018/061672
Authority: WO
Inventors: Udo Kaess; Klaus Bauer
Original assignee: Robert Bosch Gmbh
Priority date: 2017-06-28
Filing date: 2018-05-07
Publication date: 2019-01-03
Also published as: DE102017210894A1; CN110832957B; CN110832957A; EP3646678A1

Abstract

The invention relates to an electronic module (1), which comprises a substrate printed circuit board (2) composed of an insulating material having a first surface (21), a second surface (22) facing away therefrom and a circumferential side face (23) and furthermore metallization areas (24) arranged on the first surface (21) of the substrate printed circuit board (2), electronic components (31, 32), which are electrically contact-connected to the metallization areas (24) on the first surface (21), connection contact faces (26) arranged on the second surface (22) of the substrate printed circuit board (2) and a mould compound (4) arranged over the electronic components (31, 32) on the first surface (21), which mould compound completely covers the first surface (21) over the components (31, 32) up to the circumferential side face (23). It is proposed that a circumferetnial edge region (25), which directly adjoins the circumferential side face (23), on the first surface (21) of the substrate printed circuit board (2) is free of metallization areas (24) and the mould compound (4) in this circumferential edge region (25) is in direct contact with the insulating material of the substrate printed circuit board (2). The invention further relates to a method for producing such an electronic module.

Description

description

title

Electronic module and method for producing an electronic module prior art

In the prior art electronic modules are known which have packaged electronic components and can be equipped, for example, for speed detection, as angle sensors, or for position or acceleration detection on printed circuit boards of control units. Such electronic modules are also produced as LGA package (LGA = Land Grid Array). Become an LGA package

Terminal contact surfaces of the arranged on the first surface ASICs or integrated circuit on the opposite second surface in the form of a checkered contact field (the so-called grid array) executed. In an LGA package, semiconductor devices that are designed as bare-die devices are populated together with passive SMD resistors (SMD = Surface Mounted Device) on a substrate circuit board. As the molding compound, a thermoset is placed over the electronic components on the first surface. The

Electronic modules are used for different purposes in consumer electronics and automotive electronics. Also known is the production of such electronic modules in a benefit in which from a benefit board by

Singling a variety of electronic modules is obtained. The well-known

In this case, manufacturing processes use galvanic coating methods for producing metallization areas on the first and second surfaces of the substrate circuit board.

Disclosure of the invention

The invention relates to an electronic module which has a substrate circuit board made of an insulating material having a first surface, a second surface remote therefrom and a peripheral side surface. Metallization surfaces are arranged on the first surface of the substrate circuit board. On the second surface the substrate circuit board are arranged terminal contact surfaces. electronic

Components are electrically contacted with the metallization areas on the first surface. Over the electronic components on the first surface a molding compound is arranged for protection, which the first surface over the

Completely covers components up to the circumferential side surface.

According to the invention, it is proposed that a circumferential edge region immediately adjacent to the circumferential side surface of the substrate circuit board is free of metallization surfaces on the first surface of the substrate circuit board and the molding compound is in direct contact with the insulating material of the substrate circuit board in this peripheral edge region.

Furthermore, the invention relates to a method for producing such

Electronic module in use, wherein the production of the metallization by a chemical deposition process on copper surfaces at least on the first surface of the Nutzleiterplatte takes place, with a peripheral side immediately adjacent to the circumferential side peripheral edge region on the first surface of the Nutzleiterplatte and a portion on the first surface of the Nutzleiterplatte, which adjoins dividing lines intended for subsequent separation, free from

Metallization surfaces is.

Advantages of the invention

The electronic modules according to the invention are also advantageous for use in

Transmission fluid of a motor vehicle transmission suitable. There is no additional for this

Packaging or cover of the electronic module required so that it can be used as a so-called 1 st-level package of protected by the molding compound electronic components. The electronic module offers the advantage over the conventionally used known electronic modules

Transmission fluid to be resistant and provide a fluid-tight packaging of the electronic components.

The known electronic modules have the disadvantage that they have manufacturing reasons in the edge region of the substrate circuit board copper surfaces, which are exposed even after the cover with molding compound on the side walls of the electronic module. In the known electronic modules, the production takes place in the PCB benefits, with metallization by a galvanic coating process on copper surfaces the first surface of a utility PCB. Since a galvanic method is used, the areas which adjoin the separating lines for subsequent separation of the electronic modules can not be kept free of metallization surfaces. After the application of molding compound and the separation along the parting lines, therefore, the metalization surfaces are also cut so that they are exposed on the side walls of the separated electronic modules. However, exposed copper surfaces are to be regarded as critical in aggressive gear fluid, since corrosion and the deposition of metal chips can lead to malfunction. The electronic modules according to the invention advantageously have an encircling, directly adjacent to the circumferential side surface of the substrate circuit board

Edge region on the first surface of the substrate circuit board, which is completely free of Metallisierungsflächen. The molding compound is therefore in this edge region circumferentially in direct contact with the material of the substrate circuit board. This creates a solid and gap-free connection, so that no transmission fluid can penetrate in the connection area of molding compound and printed circuit board material.

The electronic modules can be connected via the connection pads on the second

Surface of the substrate circuit board, for example by means of spring elements, an SMD assembly with a rack, such as a polyimide film or a flexible or rigid circuit board can be electrically contacted in a simple manner.

Advantageously, therefore, use as a LGA package is possible.

The invention enables a cost reduction in the production and a reduction of the production steps. The electronic components are not exposed to strong mechanical stresses, since no stress-building, fluid-tight secondary packaging is required. In addition, the geometric dimensions can be advantageously reduced. Advantageous embodiments and further developments of the invention are made possible by the features contained in the dependent claims.

Characterized in that molding compound with the circumferential side surface perpendicular to the first surface of the substrate circuit board at least a smooth side wall of the

Electronic module forms, is a continuous, edge and stepless transition region of Mold compound and side surface achieved, so that there is no vulnerability, at the aggressive transmission fluid can penetrate into the packaging.

Advantageously, a solder resist can be arranged on the first surface of the substrate circuit board, wherein the metallization surfaces and the peripheral edge region are excluded from the application with solder mask. The solder mask facilitates the application of the electronic components on the metallization surfaces in SMT technology (SMT = Surface Mount Technology). Since the peripheral edge region does not have to be covered with Lötstopplack metallization, also needs the

Lötstopplack not be applied in the edge region, so that the advantage of adhering in the peripheral edge region directly on the material of the substrate circuit board molding compound is also achievable with a Lötstopplack.

The metallization surfaces are particularly advantageous as ENEPIG coating (ENEPIG = Electroless Nickel Electroless Palladium Immersion Gold) with one on one

Copper surface of the first surface of the substrate printed circuit board applied coating of a NiP layer, a Pd layer and an Au layer formed.

Also advantageous is a method for producing such an electronic module in which the production of the metallization by a chemical

Deposition method on copper surfaces on the first surface of the

Utility board done. The use of a chemical deposition process avoids the need for an electrodeposition electrode disposed on the first surface of the utility board to provide continuous electrical connection. So not only the immediate to the circumferential side surface

adjacent peripheral edge region on the first surface of the Nutzleiterplatte, but also the area adjacent to the parting lines on the first surface of the Nutzleiterplatte are advantageously kept free of Metallisierungsflächen. Brief description of the drawings

Fig. 1 shows a cross section through a first embodiment of a

electronic module according to the invention,

FIG. 2 shows a plan view of FIG. 1 without the molding compound, FIG.

3, 4 and 5 show contacting possibilities of the electronic module on a rack, 6 shows a flow chart of the manufacturing method according to the invention of an electronic module in useful production,

Fig. 7 shows an intermediate piece produced during production without the molding compound. Embodiments of the invention

Fig. 1 shows a cross section through an inventive electronic module 1. The electronic module 1 is formed, for example cuboid and has a

Total height h1 + h2, for example, 1550 μηη, a depth 11 of 4000 μηη and a width 12 of, for example, 5000 μηη on. The electronic module 1 has a

Substrate circuit board 2 with a flat, first surface 21, facing away from a flat, second surface 22 and a circumferential side surface 23 on. The

Substrate circuit board 1 has, for example, a thickness h2 of about 250 μηη. The substrate circuit board may for example consist of an insulating halogen-free

High temperature material exist. The high temperature material can be a

Mixture of bismaleimide and triazine resin, a so-called BT material.

In the insulating material of the substrate circuit board 1, not shown electrical interconnector and interconnects are introduced, which connect about 20 μηη thick copper surfaces on the first surface 21 with terminal pads 26 on the second surface 22 electrically. The copper surfaces on the first surface 21 are

For example, provided with a chemically produced ENEPIG coating

(ENEPIG = Electroless Nickel Electroless Palladium Immersion Gold), as will be explained later. Made by the ENEPIG coating of copper surfaces

Metallization surfaces 24 can be seen in FIG. 1. Furthermore, a solder resist 27 is applied to the first surface 21 of the substrate circuit board 2, wherein a peripheral edge region 25 and the metallization 24 are excluded from the application with solder mask.

Electronic components 31, 32 are soldered in SMD technology with the metallization 24. The electronic component 31 may, for example, be a bare-the-component (that is to say a caseless electronic semiconductor component), for example an integrated circuit. The four components 32 shown in FIG. 2 may be, for example, SMD resistors or SMD capacitors. As can be seen in FIG. 1, a molding compound 4 is arranged above the electronic components 31, 32 on the first surface 21. The molding compound 4 is, for example, a duroplastic, which is used as a molding compound in the LGA package technology. The thickness h1 of the molding compound 4 at the edges of

Elekronikmoduls 1 is for example 1300 μηη.

The molding compound 4 completely covers the first surface 21 over the components 31, 32 up to the circumferential side surface 23. Fig. 2 shows a plan view of the

Substrate circuit board 2 without the molding compound. 4

As can be clearly seen in FIG. 1 and FIG. 2, the molding compound 4 is in direct contact with the insulating material of the first surface 21 in a peripheral edge region 25 of the first surface 21 immediately adjacent to the circumferential side surface 23

Substrate circuit board 2, since in the edge region 25 neither metallization 24 still solder resist 27 are present. The resin material of the molding compound 4 and of the material of the substrate circuit board 2 thereby form in the edge region 25 a particularly dense and firm connection which reliably avoids the penetration of transmission fluid.

As can also be seen in FIG. 1 in conjunction with FIG. 2, the molding compound 4 with the circumferential side surface 23 forms perpendicular to the first surface 21 of FIG

Substrate circuit board 2 four smooth rectangular side walls 12 of the cuboid electronic module. 1

Fig. 3, Fig. 4 and Fig. 5 show different contacting possibilities of

The module carrier 5 may be for example a conventional FR4 printed circuit board (PCB) or a polyimide film or a flexible circuit board (FCC) or another carrier substrate of electronic assemblies. As shown in FIG. 3, the electronic module 1 can be contacted with the contact pads 26 directly with contact surfaces on the top of the Braugruppenträger 5. This can be done, for example, in SMD technology and by soldering.

Fig. 4 shows a contacting possibility via spring contacts 10, which the

Connect terminal pads 26 with contacts of a subrack, not shown. Fig. 5 shows a contacting possibility via contact tabs 1 1, which the

Connect terminal pads 26 with contacts of a subrack, not shown.

In the following, a method for producing the above-described electronic module 1 in a production production will be described with reference to FIGS. 6 and 7.

First, in a first step 100, a utility board 200 is provided.

The utility board 200 serves to simultaneously produce a plurality

Electronic modules, where certain manufacturing steps can be carried out together in one production in the benefit. The utility board 200 consists of an insulating material having a first surface 210, a second surface not facing away from FIG. 7, and a peripheral side surface 230. The utility board 200 includes, for example, three substrate boards 2a, 2b, and 2c along separation lines 252 are connected to a common benefit board. The insulating material of the utility board 200 may be the high-temperature material of bismaleimide and triazine resin already described above. In the insulating material of the substrate circuit boards 2 a, 2 b, 2 c associated wiring structures of electrical interconnects and interconnects are introduced, electrically connect the copper surfaces on the first surface 210 with copper surfaces on the second surface facing away therefrom.

In a step 101, the metallization areas 24 on the first surface 210 and optionally additionally the connection pads 26 on the second surface of the Nutzleiterplatte 200 are prepared. In this case, the metallization surfaces 24 and optionally additionally the terminal contact surfaces 26 are produced by a chemical deposition process. The chemical deposition method may be provided, for example, as an ENEPIG coating method. In this

Method is applied to the example 20μηι thick copper layer, a 3-8 μηη thick NiP layer. On the NiP layer, for example, 0.05-0.15 μηη thick Pd layer is applied and on the Pd layer and an example 0.05 to 0.1 μηη thick Au layer.

As a result of this manufacturing process, not only remains at the circulating

Side surface 230 immediately adjacent, peripheral edge region 250 on the first Surface 210 of the Nutzleiterplatte 200 free of metallization 24, but also an adjacent to the parting lines 252 area 251st

In a further method step, a solder resist 27 can be applied locally, the metallization surfaces 24, the peripheral edge region 250 and the region 251 adjoining the parting lines 252 being excluded from the solder resist.

In a further step 102 finally, the assembly and contacting with the electronic components 31 a, 32 a, 31 b, 32 b, 31 c, 32 c, wherein the assembly of the Nutzleiterplatte 200 can be performed, for example in a common manufacturing step as SMD assembly, wherein the electronic components 31 a, 32 a, 31 b, 32 b, 31 c, 32 c are soldered to the metallization 24.

In step 103, molding compound is applied to the first surface 210 of the utility board 200, the molding compound 4 completely covering the first surface 210 above the electronic components up to the peripheral side surface 230. The result of the manufacturing step 103 is that exemplified in FIG

Intermediate piece 12 from the Nutzleiterplatte 200 and arranged thereon electronic components 31 a, 32 a, 31 b, 32 b, 31 c, 32 c, wherein the molding compound 4 in Fig. 7 is not shown.

Finally, in a step 104, a separation of the thus obtained

Intermediate piece 12 along separating lines 252. Hereby, the intermediate piece 12 along the dividing lines 251, for example sawed and the Nutzleiterplatte 200 in three substrate circuit boards 2a, 2b, 2c separated. In this way, for example, three or more similar electronic modules 1, as shown in Fig. 1, obtained in the benefit.

Claims

claims

1 . Electronic module (1), comprising:

- A substrate circuit board (2) made of an insulating material having a first surface (21) facing away from a second surface (22) and a circumferential

Side surface (23),

- On the first surface (21) of the substrate circuit board (2) arranged

Metallization surfaces (24),

electronic components (31, 32) which are electrically contacted with the metallization surfaces (24) on the first surface (21),

- On the second surface (22) of the substrate circuit board (2) arranged

Terminal contact surfaces (26)

- And one on the electronic components (31, 32) on the first surface (21) arranged molding compound (4), which the first surface (21) over the components

(31, 32) to the peripheral side surface (23) completely covering, characterized in that a to the circumferential side surface (23) immediately adjacent peripheral edge region (25) on the first surface (21) of the substrate circuit board (2) free of Metallisierungsflächen (24) is and the molding compound (4) in this peripheral edge region (25) in direct contact with the insulating material of

Substrate circuit board (2) is.

2. Electronic module according to claim 1, characterized in that the molding compound (4) with the peripheral side surface (23) perpendicular to the first surface (21) of the substrate circuit board (2) forms at least one smooth side wall (12) of the electronic module (1).

3. Electronic module according to claim 1 or 2, characterized in that on the first surface (21) of the substrate circuit board (2) a Lötstopplack (27) is applied, wherein the metallization (24) and the peripheral edge region (25) of the application with Lötstopplack (27) are excluded.

4. Electronic module according to one of the preceding claims, characterized in that the metallization (24) is designed as ENEPIG coating, with a coating applied to a copper surface of the first surface of a coating of a NiP layer, a Pd layer and an Au layer ,

5. Electronic module according to one of the preceding claims, characterized in that the electronic module (1) is suitable for use in the hydraulic fluid of a transmission and in particular is designed as a sensor module and.

6. A method of manufacturing an electronic module comprising the steps of:

Providing (100) a utility board (200) of an insulating material having a first surface (210), a second surface facing away therefrom and a peripheral side surface (230), and terminal pads disposed on the second surface of the utility board (200),

Producing (101) metallization areas (24) on the first surface (210) of the utility board (200),

Assembly and contacting (102) of electronic components (31 a, 32 a, 31 b, 32 b, 31 c, 32 c) with the metallization surfaces (24);

- applying (103) molding compound (4) over the electronic components (31 a, 32 a, 31 b, 32 b, 31 c, 32 c) on the first surface (210), wherein the molding compound (4) the first surface (210) over the electronic components to the peripheral side surface (230) completely covers, whereby an intermediate piece (12) of the

Nutzleiterplatte (200) and the electronic components arranged thereon (31 a, 32 a, 31 b, 32 b, 31 c, 32 c) and the molding compound (4) is formed and

Separating (104) the intermediate piece (12) thus obtained along dividing lines (252) to obtain a plurality of useful electronic modules (1), characterized in that the formation of the metallization areas (24) by a chemical deposition method on copper surfaces the first surface (210) of the utility board (200) is formed, wherein a peripheral edge region (250) immediately adjacent to the circumferential side surface (230) on the first surface (210) of the utility board (200) and adjacent to the separation lines (252) Area (251) on the first surface (210) of the Nutzleiterplatte (200) free of

Metallization surfaces (24).

7. The method according to claim 6, characterized in that the

Metallisierungsflächen (24) is designed as ENEPIG coating, with a coated on a copper surface of the first surface coating of a NiP layer, a Pd layer and an Au layer.

8. The method according to claim 6, characterized in that the singling (104) by sawing the intermediate piece (12).

9. The method according to any one of claims 6 to 8, characterized in that prior to the step of equipping and contacting (102) of electronic components (31 a,

32a, 31b, 32b, 31c, 32c) is applied a solder resist (27) on the first surface (210) of the Nutzleiterplatte (200), wherein the metallization (24), the peripheral edge region (250) and the dividing lines (252) adjacent area (251) is excluded from the application with solder mask (27).