WO2017220319A1

WO2017220319A1 - Arrangement having a carrier and having a housing body, and method for producing an arrangement having a component

Info

Publication number: WO2017220319A1
Application number: PCT/EP2017/063757
Authority: WO
Inventors: Eckart Schellkes; Florian Grabmaier
Original assignee: Robert Bosch Gmbh
Priority date: 2016-06-20
Filing date: 2017-06-07
Publication date: 2017-12-28
Also published as: TW201810449A; DE102016210940A1

Abstract

An arrangement (1) having a carrier (3) and having a housing body (4) is disclosed. The carrier (3) is arranged on the housing body (4) and delimits a cavity (9) for receiving at least one component (16). In the cavity (9), there is provided a passivation (19) composed of a first material in a first region (21) and of a second material in a second region (22) which differs from the first region (21). The first material has a higher modulus of elasticity and/or higher hardness than the second material, wherein the first region (21) covers a partial surface (20) of the carrier (3), and the second region (22) covers a partial surface (14) of the housing body (4). The component (16) is arranged in the second region (22).

Description

description

title

Arrangement with a carrier and a housing body, and method for producing a device with a component

The invention generally relates to a housing for components.

In particular, the invention relates to a housing for electronic and / or micromechanical components, wherein the housing has a carrier and a housing body with a cavity which is provided, for example, for receiving a sensor element.

State of the art

Housings for electronic components are subject to different requirements depending on the purpose, resulting from the nature of the arranged in the housing components. Housings for sensors are known.

DE 10 201 1 084 582 B3 describes a micromechanical sensor device with mold packaging and a corresponding production method. The sensor device comprises a substrate, one on the

Substrate mounted circuit chip and a Moldverpackung in which the circuit chip is packaged. The Moldverpackung has a cavity above the circuit chip in which a sensor chip is provided, and within the cavity, a through hole through which an electrical connection of the

Sensor chip is guided.

Further, it is desirable to provide a housing that simultaneously accommodates different types of devices, such as sensors and electronic components for the sensors. The components should be sufficiently protected against environmental influences, wherein Furthermore, a possibility for a secure contact of the respective

Component must be guaranteed. In addition, if necessary, a

sufficient access to the device are made possible. Thus, with a sensor element, so that a measurement can be carried out, a media access to the sensor element is usually required. It should also be noted that sensor elements can be comparatively sensitive to a thermomechanical and mechanical stress occurring between the housing and the carrier.

There is thus a need for a housing for components, in which each component is sufficiently passivated and is protected against environmental influences and at the same time no negative influence, such as thermo-mechanical and mechanical stress, is exerted on the component.

Disclosure of the invention

There are an arrangement with a support and a housing body according to independent claim 1 and a method for producing an arrangement with a device according to the independent

Claim 9 provided.

Further embodiments are specified in the dependent claims.

According to a first aspect of the invention, an arrangement is provided with a carrier and a housing body, wherein the housing body is arranged on the carrier and defines a cavity for receiving at least one component. In the cavity, a passivation of a first material in a first region and of a second material in a second region is provided, wherein the second region is different from the first region. In this case, the first material has a higher modulus of elasticity and / or a higher hardness compared to the second material. Further, the first area covers a partial area of the carrier, and the second area covers a partial area of the case body. The component is arranged in the second region. With such an arrangement, the passivation of components can be significantly improved, whereby a two-part passivation is created, which can meet in the first region and the second region of the passivation respectively different requirements for the passivation. Thus, a two-part encapsulation can be applied, with which mutually exclusive requirements can be selectively realized by two substances. Furthermore, the robustness of Kavitätspackages can be significantly increased compared to the prior art.

According to a preferred embodiment, the cavity forms a passage opening leading to the carrier, which is at least partially filled with the first material.

For this purpose, a material can be advantageously selected for the first region that is better suited for protecting a partial surface of the carrier than other materials or for the second material, and

Accordingly, it has a sufficiently high modulus of elasticity and / or a correspondingly high hardness. Furthermore, a special robust passivation of the carrier can be achieved in such a way.

Further, the housing body may form a cavity defining projection, wherein the component is disposed on the projection and the second material covers the projection.

In this case, advantageously, the second material can be chosen so that the partial surface of the housing body or a component located thereon is protected, which is exposed at the same time as little as possible thermodynamic and mechanical stress. In particular, a

Stress-sensitive device that has a different coefficient of expansion and / or a different flexibility compared to a plastic of the carrier, not mounted on the support, whereby thermal stresses, such as arise during soldering, and mechanical and thermo-mechanical stress on the device can be avoided. Further, the device in the second region sufficiently well against a Environmental stress, such as penetrating moisture, are protected.

According to one embodiment of the invention, the component in the second region is designed as a sensor element, in particular as a pressure sensor.

As a result, a sensor device can advantageously be realized in which the retention of the sensor characteristic curve is ensured, in that a negative influence on the sensor characteristic can be prevented, in particular during assembly. In particular, in this case the advantages of a premold housing can be used, in which the sensor is usually very stiff on one

Plastic bottom is mounted, while the other sides of the sensor are surrounded only by a suitable, gentle passivation.

Furthermore, between the sensor element and an outside of the

Housing body fluid communication in the second material and / or in the

Be formed housing body.

As a result, if necessary parts of the sensor element remain free, wherein advantageously a sensor device is provided with simply realized feed openings, for example for supplying a gas pressure to the sensor. In particular, in this case a feed opening is easier to implement than in a pure mold housing, where the component or the sensor is surrounded by the housing body.

Preferably, another component is embedded in the housing body.

This device, which is preferably chosen so that it does not require media access, can be particularly well protected against environmental influences, since it is surrounded directly by the housing body.

According to an advantageous embodiment, the first region has a smaller thickness than the second region, wherein the first material comprises, for example, an epoxy resin or a lacquer. Thus, advantageously, the first part of the two-part passivation can protect the carrier with a hard and thin encapsulation. The dense and hard encapsulation keeps media damaging much longer away from the sensitive structures compared to softer material. In particular, in the first range, a low permeability to media such as air, moisture, and exhaust gases, halides, bases or acids can be achieved. Furthermore, the thin application ensures that no thermomechanical stresses lead to cracks and delamination, which would otherwise be expected for a larger volume.

The second material may comprise a gel, in particular a silicone gel.

Such a material has over plastics, such as

Epoxides, the advantage that it can be used as a full potting over the device. In addition, the fact that it is used in the second area, stress-induced characteristic changes as well as cracks and delamination due to thermo-mechanical stress can be avoided in the second area.

Overall, therefore, the second part of the two-part passivation can protect both the sensor element and the volume of the cavity with an incompressible casting of soft material with a low modulus of elasticity. The

Incompressibility is a prerequisite for many applications

Ensuring an unaffected signal transmission, and the softness helps to avoid an influence by thermo-mechanical stresses on the sensor element.

The housing body may be made for example by plastic injection molding.

Thereby, the housing body can be manufactured in an efficient manner, while at the same time, by the plastic, further a good protection of the components against environmental influences can be ensured. It may advantageously be a production of a mold-premold housing with overmolded Components are realized on a circuit board or a leadframe as a carrier with a Premoldkavität and a two-part passivation.

According to one embodiment, it may further be provided that the component is connected by a wire connection to an electrical connection on the carrier, wherein the connection is arranged in the first region and is covered by the first material, wherein the wire bond passes through the first region and through the first region second area is guided.

In particular, in a combination with the above-mentioned thin, hard casting in the first region, this embodiment can be used particularly advantageous in a sensitive circuit board as a carrier, wherein on the circuit board bond areas for contacting the in the second area

arranged component can be provided. Due to the thin, local application in the Bondfußbereich the hard medium of

Sensor element whose function can be disturbed by thermomechanical stress kept away. The two-part passivation can advantageously both a dense protection of the printed circuit board and the bonding connection on the

Provide printed circuit board in front of media such as exhaust gases and halides, without exerting a negative influence of a hard material.

According to a second aspect of the invention, there is provided a method of manufacturing a device with a device, the method comprising the steps of: providing a carrier, encasing the carrier with a molding material so as to form a cavity, the cavity extending to one Top of the carrier ranges, placing a device in the cavity, introducing a first material into the cavity, wherein the first material is applied to the surface of the carrier in the cavity, and applying a second material in the cavity, wherein the device of the second Material is covered and wherein the second material has a lower modulus of elasticity and / or a higher hardness compared to the first material.

According to a preferred embodiment, the second material is also applied to the first material. It is further preferred that the first material is applied in a thinner layer than the second material.

Furthermore, the first material may cover the entire surface of the carrier in the cavity, and the second material may cover the entire device.

Overall, the aspects of the invention advantages of both a mold housing, in which the components are mounted on a support, such as a circuit board, and then molded with plastic, as well as a premold housing, in which a carrier is first encapsulated, with areas beispielswiese are kept for electrical contacting and the device is then added and contacted, can be advantageously used, wherein the aspects of the invention, an improved passivation is provided. In other words, a combination of both of the above-mentioned types of housing may be provided, that is, assembled components may be overmolded and recesses may be kept free to thereafter add further components, and at the same time passivation for all components may be ensured in a manner which takes particular account of the function of the components.

In this case, components which have a low sensitivity to stress and require no gas access can be gold-plated, whereas a stress-sensitive sensor element is constructed in a molded premold cavity. As a result, the protection of the molded components is achieved against environmental influences while ensuring that the

Sensor element has a connection to the outside world, since it is located in the Premoldkavität.

In particular, a circuit board-based mold-premold housing can advantageously be realized in order to protect components which do not require media access in the molding body, and at the same time to produce a premold region in which a sensor element with a two-part passivation is protected against media influences. The aspects of the invention can be realized both with a leadframe and with a substrate as a carrier.

Brief description of the drawings

Preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. Show it:

1 shows a schematic cross-sectional view of an arrangement with a carrier and a housing body, according to a first embodiment of the invention,

2 shows a schematic plan view of an arrangement with a carrier and a housing body, according to a second embodiment of the invention,

Fig. 3 is a schematic cross-sectional view of an arrangement with a carrier and a housing body, according to a third embodiment of the invention, and

4 shows a flow diagram of a method for producing a device with a component, according to an embodiment of the invention.

Description of embodiments

In the figures, like reference numerals designate the same or functionally identical elements.

Fig. 1 shows a schematic cross-sectional view of a

Sensor assembly 2 configured arrangement 1 with a support 3 and a housing body 4 according to a first embodiment of the invention. The carrier 3 serves as a substrate for the housing body 4, and the housing body has an upper side 6 and a lower side 5, the lower side 5 largely covering the carrier 3. The carrier 3 can in principle be configured as a leadframe or printed circuit board, wherein according to the embodiment shown here, the carrier 3 a printed circuit board is, which is equipped with a variety of electronic components 7, of which in the drawing, a component 7 is shown as an example. The component 7 is encased by the housing body 4 and is electrically connected to the circuit board, ie the support 3, by means of conductive connections 8. The conductive connections 8 have, for example, wire bonds. According to the embodiment shown here, the housing body 4 is made of a plastic material and forms a chip housing for the component 7. In this case, the housing body 4 can be manufactured, for example, by injection molding. Since the component 7 is encased by the housing body 4, which thus acts as a mold housing, as shown in the drawing, the component 7 is protected in the housing body 4 from environmental influences.

The housing body 4 further defines a cavity 9 defined by side walls 10, i. Inner walls of the housing body 4, is limited. In a plan view, the limiting side walls 10, as shown in Fig. 2, be connected to each other at the outer periphery of the cavity 9. In the cross-sectional view shown in Fig. 1, the cavity 9 has a part

Step-shaped cross-section, by the housing body 4 is formed so that the cavity 9 is further limited by a projecting into the cavity 9 projection 1 1. In the cross-sectional view, a bottom 13, a top 14, and a side wall 15 of the projection 1 1 are also visible.

The projection 1 1 of the housing body 4 covers a partial surface of the support 3, wherein the bottom 13 of the projection 1 1 is a part of the bottom 5 of the housing body. The side wall 15 of the projection 1 1 extends parallel to the side wall or inner wall 10 of the housing body 4, wherein the

Housing body, however, is not limited to such a shape. Furthermore, the cavity 9 forms a passage opening 12 leading to the carrier 3, so that the carrier 4 is not covered by the housing body 4 in a region located below the passage opening 12.

The cavity 9 serves to receive a component 16 which is not placed directly on the printed circuit board 3. The device 16 is disposed on the top 14 of the projection 1 1 and by means of a wire connection 17 with the PCB 3 connected. On the circuit board 3 associated bond feet 18 are also provided as connections for the wire bonds 17. The bonding feet 18 are elements of a structure of the construction of the printed circuit board 3 which is not shown in greater detail in the drawing. The component 16 in the cavity 9 is here a sensor element which may have a micromechanical sensor element. In particular, the component 16 may be a pressure sensor. The associated electronics of the

Sensor element is at least partially placed on the circuit board 3. The electronics have, for example, the component 7 and may also have other elements that are not shown in detail for simplicity in the drawing. These can also be provided in the region of the passage opening 12 on the printed circuit board 3.

In the cavity 9 a passivation 19 is provided which is suitable for both passivating the device, i. Sensor element 16 and for passivating a portion of the circuit board 3, which is located in the region of the passage opening 12 of the cavity 9, is used. For this purpose, the passivation 19 has a first region 21 made of a first material and a second region 22 made of a second material. The first region 21 of the passivation 19 covers a partial surface of the printed circuit board 3, which is not already covered by the underside 5 of the housing body 4. The second region 22 of the passivation 19 covers a partial surface 14 of the

Housing body 10, more specifically, including the top 14 of the projection 1 1. Furthermore, the second region 21 also covers part of the side surface 10. In this way, the sensor element 16 arranged on the projection 11 is arranged in the second passivation region 19

or embedded in the second material. In the shown

Embodiment, the second region 22 of the passivation 19 also extends beyond the first region 21, so that the first region 21 and the second region 22 have a common interface 20, which according to this embodiment is parallel to the printed circuit board 3. This allows the

Passivation 19 are made very easy and the robustness can be increased. The thickness di of the first region 21 is smaller than the thickness d2 of the second region 22. Specifically, the thickness d2 of the second region 22 is selected such that the second region 22 surrounds the sensor element 16, whereas the first region 21 covers the carrier 3. The two regions 21, 22 of the passivation 19 can take any conceivable suitable forms, which depend on the type, number, and arrangement of the components to be protected. Here, the term "area" in this context is not limited to the description of a two-dimensional extent, as already apparent from the above embodiment, and "different" means that the areas have at most common interfaces but no identical volume areas.

The first material comprises, for example, epoxy resin or lacquer, and the second material comprises, for example, a gel, in particular a silicone gel.

The cavity 9 is designed as a so-called premold cavity, wherein the housing body 4 acts as a premold package or premold housing which protects a surface of the support 3 covered by the underside 5 of the housing body 4. Further, since the component 7 is molded in the housing body 4, a Mold-Premold housing with two-part passivation is thus realized by the arrangement 1 and in particular by the housing body 4.

2 shows a schematic plan view of an arrangement 24 with a carrier 3 and a housing body 4, according to a second embodiment of the invention. The arrangement 24 substantially corresponds to the arrangement 1 in Fig. 1. In contrast to the first embodiment according to Fig. 1, the carrier 3 according to the second embodiment as a leadframe, i. designed as a connection frame. The leadframe 3 is arranged under the housing body 4, this being according to the plan view shown in FIG. 2 of a position behind the

Housing body 4, with respect to a direction in the leaf level, corresponds. As shown in FIG. 2, the leadframe 3 has a plurality of

Ports 25, which are shown only schematically in the drawing. The terminals 25 may serve in a variant of this embodiment for mounting the assembly 24, but are not limited in principle to a particular shape.

The arrangement 24 furthermore has a multiplicity of components 7, 26 molded in the housing body 4, two components 7, 26 being shown by way of example in the drawing for the sake of clarity. Not explicitly shown is the electronic connection on the circuit board between the components 7, 26 on the one hand and the sensor element 16 on the other. As further shown in Fig. 2, the side walls 10 of the cavity form a closed rectangle. The shape and arrangement of the cavity 9 and the through hole 12 is not limited to a particular shape and can be adjusted depending on the application. So is after this

Embodiment, the width bi2 of the through hole 12 is smaller than the width bg of the cavity 9. According to other embodiments, the width of the through hole 12 but also the width of the cavity 9 correspond.

3 shows a schematic cross-sectional view of an arrangement 1 with a carrier 3 and a housing body 4, according to a third

Embodiment of the invention. The arrangement 1 according to FIG. 3 essentially corresponds to the arrangement in FIG. 1. In contrast to FIG. 1, in FIG. 3 additionally a fluid connection 23 is shown, which as one through the second

Area 22 leading through hole is configured. In other words, the second material is recessed in a partial region of the second region 22 above the sensor element 16. As a result, for example, from the

Sensor element 16 to be transmitted pressure waves or pressure changes are better transmitted. According to other embodiments, is based on a separate

Fluid connection 23 is omitted, wherein the second material itself serves as a carrier of the transfer or is chosen so that the medium to be detected is not shielded in a disadvantageous manner. FIG. 4 shows a method for producing an arrangement with a

Component, according to an embodiment of the invention. The method basically has the following steps. In a step S100 we provide a carrier. The carrier may be a leadframe or a printed circuit board. In this case, the carrier may have a suitable structuring in the form of lines or terminals and components placed thereon. In one step

S101, the carrier is repolished with a molding material, wherein a cavity is further formed. The cavity serves to accommodate further components. In particular, a component can be accommodated in the cavity that is arranged in the cavity on the housing body instead of on the carrier. The cavity extends to the surface of the carrier. In a step S102, then a component placed in the cavity. In a step S103, a first material is introduced into the cavity, wherein the first material is applied to the surface of the carrier. In a step S104, a second material is introduced into the cavity, wherein a component, which is placed in the cavity, is covered by the second material. In this case, the materials are selected so that the second material has a lower modulus of elasticity and / or a higher hardness compared to the first material.

It will be understood that the order of the steps may be varied as needed and not strictly according to the order shown in FIG. Basically, it depends on the selected materials and their

Passivation property and eventual influence on the covered or embedded elements and surfaces. For example, it is conceivable that the second area is first produced by means of a mask, and then the first material is applied. In such an embodiment, a fluid connection designed as an opening may also be provided in the first region. Furthermore, it is also conceivable, for example, although this is not explicitly stated in the above description, that first a housing body is formed, and then the cavity is formed in the housing body.

Claims

claims

1 . Arrangement (1) with a carrier (3) and a housing body (4), which is arranged on the carrier (3) and delimits a cavity (9) for receiving at least one component (16), wherein in the cavity (9) a passivation (19) of a first material in a first region (21) and of a second material in a first region (21)

different second region (22) is provided, wherein the first material in comparison to the second material higher

Young's modulus and / or a higher hardness, wherein the first region (21) covers a partial surface of the carrier (3) and the second region (22) covers a partial surface (14) of the housing body (4), wherein the

Component (16) in the second region (22) is arranged.

2. Arrangement (1) according to claim 1, wherein the cavity (9) forms a to the carrier (3) leading through opening (12) which is at least partially filled with the first material, and wherein the housing body (4) further comprises a Cavity (9) limiting projection (1 1) is formed, wherein the component

(16) on the projection (1 1) is arranged and the second material, the projection (1 1) covered.

3. Arrangement (1) according to claim 1 or 2, wherein in the housing body (4), a further component (7) is embedded.

4. Arrangement (1) according to one of the preceding claims, wherein the first region (21) has a smaller thickness (di) than the second region (22).

5. Arrangement (1) according to one of the preceding claims, wherein the

Housing body (4) is made by plastic molding.

6. Arrangement (1) according to one of the preceding claims, wherein the component (16) in the second region (22) as a sensor element, in particular as a pressure sensor is formed.

7. Arrangement (1) according to claim 7, wherein between the sensor element and an outer side, a fluid connection (23) in the second material and / or in the housing body (4) is formed.

8. Arrangement (1) according to one of claims 3 to 7, wherein the component (16) by a wire connection (17) with an electrical connection on the support (3) is connected, wherein the terminal (18) in the first region (21 ) and covered by the first material, the wire bond being passed through the first region (21) and through the second region (22).

9. A method for producing an assembly (1) with a component (16), comprising the steps of:

Providing a carrier (3),

- Ummolden the carrier (3) with a molding material, so that a cavity (9) is formed, wherein the cavity (9) extends to an upper side (6) of the carrier (3),

Placing a component (16) in the cavity (9),

- Introducing a first material in the cavity (9), wherein the first

Material is applied to the surface of the carrier (3) in the cavity (9), and

- Applying a second material in the cavity (9), wherein the

Component (16) is covered by the second material, wherein the second material has a lower modulus of elasticity and / or a higher hardness compared to the first material.

10. The method of claim 9, wherein the second material is also applied to the first material.

1 1. A method according to any one of claims 9 or 10, wherein the first material is applied in a thinner layer than the second material.

12. The method of claim 9, wherein the first material covers the entire surface of the carrier in the cavity, and wherein the second material covers the entire device.

13. The method according to any one of claims 9 to 12, wherein as the first material a

Epoxy resin or a lacquer is used, and wherein for the second material, a gel, in particular a silicone gel is used.