Method of embedding a component in a printed circuit board

Abstract

A method for embedding a component in a printed circuit board or a printed circuit board intermediate product, wherein the printed circuit board or the printed circuit board intermediate product comprises at least one insulating layer made of a prepreg material, and the component is fixed by the resin of the prepreg material, is characterized by the following steps: providing a combination of the layers of the printed circuit board, or of the printed circuit board intermediate product, wherein this combination includes at least one curable prepreg material; creating a clearance in the combination for accommodating the component to be embedded; covering at least the region of the clearance with a first temporary carrier layer on a first side of the combination; positioning the component to be embedded in the clearance by way of the first temporary carrier layer; covering at least the region of the clearance on the second side of the combination with a second temporary carrier layer; compressing the combination with the component, curing the curable prepreg material; and removing the temporary carrier layers.

Claims

1. A method for embedding a component in a printed circuit board or a printed circuit board intermediate product, wherein the printed circuit board or the printed circuit board intermediate product comprises at least one insulating layer made of a prepreg material, and the component is fixed by the resin of the prepreg material, characterized by a sequence of the following steps: a) providing a combination of layers of the printed circuit board or of the printed circuit board intermediate product, wherein the combination of layers includes at least one prepreg material; b) creating a clearance in the combination of layers for accommodating the component to be embedded; c) covering at least a region of the clearance with a first temporary carrier layer on a first side of the combination; d) positioning the component to be embedded in the clearance and disposed on the first temporary carrier layer wherein the component has at least one contact pad; e) covering at least the region of the clearance on a second side of the combination with a second temporary carrier layer; f) compressing the combination with the component, curing the prepreg material; g) removing the first and second temporary carrier layers thereby exposing the at least one contact pad h) utilizing the at least one contact pad of the component for directly contacting and creating conductor tracks within a plane of the printed circuit board or intermediate product, and wherein a plurality of components are embedded into the printed circuit board or into the printed circuit board intermediate product wherein each of the plurality of components are embedded in a respective clearance, wherein the components have differing thicknesses within the respective clearances, and the second temporary carrier layer is oriented with a non-adhering surface to the combination of the layers of the printed circuit board or of the printed circuit board intermediate product.

2. The method according to claim 1, characterized in that the combination of the layers of the printed circuit board or of the printed circuit board intermediate product is composed of a plurality of layers made of a prepreg material.

3. The method according to claim 1, characterized in that the combination of the layers of the printed circuit board or of the printed circuit board intermediate product is composed of a plurality of layers made of a prepreg material and copper layers located on an outside portion of both sides.

4. The method according to claim 1, characterized in that the combination of the layers of the printed circuit board or of the printed circuit board intermediate product is composed of a plurality of layers made of prepreg material and a central core.

5. The method according to claim 1, characterized in that the combination is composed of a plurality of layers made of prepreg material and a central core, as well as copper layers located on an outside portion of both sides.

6. The method according to claim 1, characterized in that the combination of the layers of the printed circuit board or of the printed circuit board intermediate product is composed of an inside layer made of a prepreg material and cores located on an outside portion of both sides.

7. The method according to claim 1, characterized in that the combination of the layers of the printed circuit board or of the printed circuit board intermediate product essentially has a thickness of the component to be embedded.

8. The method according to claim 1, characterized in that the first side of the combination is a contact side of the printed circuit board or of the printed circuit board intermediate product, and the component to be embedded is fixed in the clearance face up with respect to this contact side.

9. The method according to claim 1, characterized in that both the first side and the second side of the combination are contact sides of the printed circuit board, or of the printed circuit board intermediate product.

10. The method according to claim 9, characterized in that a component having contacts on two opposing sides of the component is being embedded.

11. The method according to claim 1, characterized in that the component is selected from a group consisting of an integrated circuit, an LED, a heat sink, a battery, a printed circuit board, and in particular a multilayer printed circuit board.

12. The method according to claim 1, characterized in that the component is an insulated material substrate part.

13. The method according to claim 1, characterized in that the first temporary carrier layer is designed in the form of an adhesive tape.

Description

DESCRIPTION OF THE DRAWINGS

(1) The invention will be described hereafter in greater detail based on one exemplary embodiment shown schematically in the drawings. In the drawings:

(2) FIGS. 1a) to 1e) show variants of a combination of the layers of the printed circuit board, or of the printed circuit board intermediate product, according to step a) of the method according to the invention;

(3) FIG. 2 shows an illustration of step b) of the method according to the invention;

(4) FIG. 3 shows an illustration of step c) of the method according to the invention;

(5) FIG. 4 shows an illustration of step d) of the method according to the invention;

(6) FIG. 5 shows an illustration of step e) of the method according to the invention;

(7) FIG. 6 shows an illustration of step f) of the method according to the invention;

(8) FIG. 7 shows an illustration of step g) of the method according to the invention;

(9) FIG. 8 shows a possible way of further processing the printed circuit board, or the printed circuit board intermediate product, produced by the method according to the invention, including a contacting of the embedded component in the plane of the contact pads of the embedded components;

(10) FIG. 9 shows a possible way of further processing the printed circuit board, or the printed circuit board intermediate product, produced by the method according to the invention, including a contacting in a contact layer located above the plane of the contact pads of the embedded components;

(11) FIG. 10 shows an illustration corresponding to step e) of the method according to the invention, wherein components of differing thicknesses were positioned in the clearances;

(12) FIG. 11 shows the further processing of the intermediate product according to FIG. 10 as defined by steps f) and g) of the method according to the invention;

(13) FIG. 12 shows a possible way of contacting the components embedded according to FIGS. 10 and 11;

(14) FIG. 13 shows an illustration of one variant in which variably thick components having the contact side in the direction of the first temporary carrier layer are positioned in the clearances;

(15) FIG. 14 shows an illustration of the result of the further processing according to the invention of the semi-finished product according to FIG. 13;

(16) FIG. 15 shows a variant of a printed circuit board, or of a printed circuit board intermediate product, produced by the method according to the invention; and

(17) FIGS. 16 to 19 show variants of the present invention using an IMS part as the component to be embedded.

DETAILED DESCRIPTION OF THE INVENTION

(18) FIGS. 1a) to 1e) show variants of the combination of the layers of the printed circuit board, or of the printed circuit board intermediate product, as they can be provided within the scope of the present invention according to step a). FIG. 1a) shows a combination 100 that is only composed of layers made of a prepreg material 1 (prepreg layers); FIG. 1b) shows a combination 100 that is composed of prepreg layers 1 and copper layers 2 located on the outside on both sides; FIG. 1c) shows a combination 100 that is composed of prepreg layers 1 located on the outside and a central core 3; FIG. 1d) shows a combination 100 that is composed of cores 3 located on the outside on both sides and an inside prepreg layer 1; and FIG. 1e) shows a combination 100 that is composed of an inner core 3, a plurality of layers made of prepreg material 1, and copper layers 2 located on the outside on both sides.

(19) FIG. 2 shows, by way of example, a combination 100 as in FIG. 1e), illustrated according to step b) with clearances 4 for accommodating the components to be embedded. After the clearances 4 have been created, according to step c) the clearances 4 in the combination 100 are covered with a first temporary carrier layer 5, for example in the form of an adhesive tape on one side of the combination 100 (FIG. 3). According to step d) and as shown in FIG. 4, the components 6 to be embedded are mounted in the clearances 4 or positioned in these in a next method step. As is apparent from FIG. 4, the components can be positioned either face down or face up, wherein in the first case they adhere with the contact side thereof, or with the contact pads 7 thereof, and in the second case they adhere with the back side 8 thereof, to the first temporary carrier layer, which is present on this first side of the combination in the form of an adhesive tape.

(20) To carry out the method according to the invention, it is essentially only necessary to cover at least the region of the clearance, or the regions of the clearances, with a first temporary carrier layer 5. In industrial production, however, it is usually easier to cover not only the region or the regions of the clearances with a first temporary carrier layer, but the entire surface area of the combination 100 with a continuous first temporary carrier layer 5.

(21) It is now apparent in FIG. 5 that, according to step e), the regions of the clearances on the second side of the combination 100 are covered with a second temporary carrier layer 9, wherein it is usually more economical here as well to cover not only the region of the clearance, or the regions of the clearances, but to apply a continuous second temporary carrier layer 9 across the entire surface area of the combination 100.

(22) FIG. 6 shows step f) of the method according to the invention, which is to say the compressing of the combination comprising the component or the components, curing the curable prepreg material 1. As is apparent from FIG. 6, the cavities of the clearances 4 are filled with resin of the layers made of prepreg material 1, so that reliable fixation of the components 6 in the combination 100 takes place during curing. Since the first temporary carrier layers 5 and 9 reliably delimit the combination 100 in spatial terms, the contact pads 7 of the components 6 are exposed after the temporary carrier layers 5 and 9 have been removed (FIG. 7) in the variant shown in the above figures for populating the combination 100 with components 6 and can, as is shown in FIG. 8, be used directly for contacting and creating conductor tracks 10, which are not shown in detail here, in the same plane a or a of the printed circuit board, or of the printed circuit board intermediate product 200. According to the variant shown in FIG. 9, however, a further composition of the printed circuit board intermediate product 200 can be created by applying further layers made of prepreg material 1 and contact layers or copper layers 2 using known methods, wherein in this case the contacting of the contact pads 7 of the components 6 takes place via what are known as microvias 11.

(23) It is apparent from FIG. 10 that components 6 having differing thicknesses can be mounted in the clearances 4 or be positioned in these, wherein in this case the second temporary carrier layer 9 is not an adhesive tape due to the circumstance that a distance exists between the components 6 and the second temporary carrier layer, and the components 6 must not be lifted off the first temporary carrier layer 5 during compression. After compressing according to step f) of the method according to the invention, a printed circuit board, or a printed circuit board intermediate product 200 is obtained, as is shown in FIG. 11, wherein a contacting of the component 6 again takes place via microvias 11 (FIG. 12). When mounting differently thick components 6 in the clearances 4 with the contact pads in the direction of the first temporary carrier layer 5, which is present in the form of an adhesive tape, the second temporary carrier layer must have a non-adhesive surface, which is oriented to the combination 100 of the layers of the printed circuit board, or of the printed circuit board intermediate product (FIG. 13). After compressing according to step f) of the method according to the invention, a printed circuit board intermediate product 201 (FIG. 14) is obtained, which can in turn be contacted again according to FIG. 8.

(24) FIG. 15 shows a variant of the present invention in which a component 6 comprising contacts 7 on two opposing sides was embedded, whereby a vertical flow of current from one side to the other side of the printed circuit board 200 is enabled.

(25) According to a preferred embodiment of the present invention, in FIG. 16 the components 6 are formed by IMS parts 6, wherein the insulator layer of the IMS part 6 is denoted by numeral 12 and the conducting layer is denoted by numeral 13. The IMS part 6 can be contacted in the conventional manner, wherein contacting via microvias 11 is also possible (FIG. 18).

(26) The use of IMS parts is particularly suited for dissipating heat, and in the case shown in FIG. 19 of heat that is introduced by LED units 14 into the printed circuit board intermediate product 200. FIG. 19 shows heat sinks 15, which additionally dissipate the heat dissipated via the IMS components 6.