WO1998049876A2 - Capacitive device on a circuit board - Google Patents

Capacitive device on a circuit board Download PDF

Info

Publication number
WO1998049876A2
WO1998049876A2 PCT/SE1998/000767 SE9800767W WO9849876A2 WO 1998049876 A2 WO1998049876 A2 WO 1998049876A2 SE 9800767 W SE9800767 W SE 9800767W WO 9849876 A2 WO9849876 A2 WO 9849876A2
Authority
WO
WIPO (PCT)
Prior art keywords
supporting structure
electrically conducting
circuit board
capacitance
capacitive device
Prior art date
Application number
PCT/SE1998/000767
Other languages
French (fr)
Other versions
WO1998049876A3 (en
Inventor
Leif Bergstedt
Original Assignee
Telefonaktiebolaget Lm Ericsson (Publ)
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget Lm Ericsson (Publ) filed Critical Telefonaktiebolaget Lm Ericsson (Publ)
Priority to AU74594/98A priority Critical patent/AU7459498A/en
Publication of WO1998049876A2 publication Critical patent/WO1998049876A2/en
Publication of WO1998049876A3 publication Critical patent/WO1998049876A3/en

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/16—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor
    • H05K1/162—Printed circuits incorporating printed electric components, e.g. printed resistor, capacitor, inductor incorporating printed capacitors
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/03—Use of materials for the substrate
    • H05K1/0306—Inorganic insulating substrates, e.g. ceramic, glass
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/02—Fillers; Particles; Fibers; Reinforcement materials
    • H05K2201/0203—Fillers and particles
    • H05K2201/0206—Materials
    • H05K2201/0209—Inorganic, non-metallic particles
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09209—Shape and layout details of conductors
    • H05K2201/0929—Conductive planes
    • H05K2201/09318—Core having one signal plane and one power plane
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/0058—Laminating printed circuit boards onto other substrates, e.g. metallic substrates
    • H05K3/0061—Laminating printed circuit boards onto other substrates, e.g. metallic substrates onto a metallic substrate, e.g. a heat sink

Definitions

  • TITLE Capacitive device on a circuit board.
  • the present invention relates to a capacitive device on a circuit board.
  • circuit boards It is common to design circuit boards as so-called LTCC- boards (Low Temperature Co-fired Ceramic).
  • LTCC- boards Low Temperature Co-fired Ceramic
  • the supporting structure of the circuit board is made of an LTCC-material.
  • a number of components are assembled, connected to each other by means of patterns of a conducting material.
  • the patterns of conducting material can, for example, be etched or printed on the surface.
  • a way of reducing that part of the surface of the LTCC- board which is occupied by conducting patterns, and thus to increase that part of the surface of the LTCC-board which can be used by components, is to let the board consist of a plurality of layers of LTCC-material, with conducting patterns on top of each layer. Connections between the surface of the board and the various layers of the board is achieved by means of so-called via-holes, i.e. holes in the board material, which have been made conducting by entirely or partially being filled with conducting material.
  • the main object of the present invention is thus to design a capacitive device in a circuit board, which is simple and inexpensive to manufacture, at the same time as it does not limit the area which can be used to assemble components on.
  • LTCC-boards often rest on a supporting structure of an electrically conducting material.
  • the reason that the supporting structure is made from an electrically conducting material is that it can then be used to shield the board electrically as well as mechanically.
  • the object of the invention is achieved by letting the invention use the electrically conducting supporting structure as a first element in the capacitance.
  • the second element of the capacitance consists of an electrically supporting element arranged in or on the circuit board.
  • a dielectric material is arranged between the circuit board and the electrically conducting supporting structure.
  • the circuit board is of the LTCC-kind, and the other element of the capacitance is arranged on that side of the circuit board which faces the electrically conducting supporting structure.
  • the dielectric material between the circuit board and the electrically conducting supporting structure is a dielectric glue, which is also used for joining the circuit board and the electrically conducting supporting structure together.
  • Fig. 1 is a simplified and enlarged side cross-section through a device according to the invention.
  • Fig. 2 is a simplified view of that side of the circuit board which faces the electrically conducting supporting material, in an alternative embodiment of the invention.
  • Fig. 1 shows a simplified and enlarged side cross-section through a device 100 according to the invention.
  • the device 100 comprises a circuit board with a supporting structure 120, preferably made of an LTCC-material.
  • a supporting structure 120 of the circuit board On one side of the supporting structure 120 of the circuit board there is arranged an electrical component 125, and on the other side of the supporting structure 120 there is arranged an electrically conducting element 170.
  • the device 100 furthermore has an electrically conducting supporting structure 130 which, in the example shown, also serves as a ground plane for the device 100.
  • the electrically conducting supporting structure 130 is separated from the element 170 and the supporting structure 120 by means of a dielectric material 140.
  • the dielectric material 140 is a dielectric glue, which then serves both to fix the supporting structure 120 relative to the supporting metal 130, and to serve as a dielectric material in the capacitance 150 formed between the element 170 and the electrically conducting supporting structure 130.
  • a capacitance 150 is formed, in the figure shown with a split arrow between the element 170 and the electrically conducting supporting structure 130.
  • this capacitance 150 is utilized, as can be seen from the figure, in order to capacitively couple a component 125 on the supporting structure 120 to ground, since the other element in the capacitance 150, the electrically conducting supporting structure 130, also serves as ground plane for the device 100.
  • the component 125 is connected to the element 170 by means of a conductor 180 and a conductor 190 in a via-hole.
  • Fig. 2 shows the underside of a supporting structure 220 in an alternative embodiment of the invention.
  • the electrically conducting supporting metal structure is not shown.
  • the figure shows how a plurality of conducting elements 270 have been arranged on that side of the supporting structure 220 which is to face the supporting metal structure.
  • a plurality of capacitances can be formed in the device according to the invention.
  • the capacitances in this embodiment have a common second plate in the (not shown) supporting metal structure.
  • the dots 205 show connecting points for the above-mentioned conductors in the via-holes .
  • the supporting structure in the circuit board does not of course need to be an LTCC- material, but can be chosen from a large number of materials which are suitable in this context, for example glass-fibre materials or plastic materials.
  • the dielectric material which separates the two elements of the capacitance is, in the example shown, glue, but can of course be any other dielectric material, adhesive or not.
  • the separating dielectric material can, for example, be air, in which case the supporting structure 120 can be fixed in place relative to the electrically conducting support 130 using, for example, isolating distances or grooves in the supporting material.
  • the second element 170, 270 of the capacitance has throughout been shown arranged on that side of the structure 120, 220 which faces the supporting structure 130, but can of course be positioned for example inside of the structure 120, 220 or on that side which faces away from the supporting structure 130.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Parts Printed On Printed Circuit Boards (AREA)
  • Combinations Of Printed Boards (AREA)

Abstract

Capacitive device (100) in a circuit board with at least one supporting structure (120), at least one electrically conducting supporting structure (130) for the circuit board, at least one dielectric layer (140) between the supporting structure (120) and the electrically supporting structure (130), with a capacitance (150), the first element of which consists of the electrically conducting supporting structure (130), and the second element of which is arranged below, in, or on the supporting structure (120).

Description

TITLE: Capacitive device on a circuit board.
TECHNICAL FIELD:
The present invention relates to a capacitive device on a circuit board.
TECHNICAL BACKGROUND OF THE INVENTION:
It is common to design circuit boards as so-called LTCC- boards (Low Temperature Co-fired Ceramic). This means that the supporting structure of the circuit board is made of an LTCC-material. On an external surface of . the supporting structure, a number of components are assembled, connected to each other by means of patterns of a conducting material. The patterns of conducting material can, for example, be etched or printed on the surface.
A way of reducing that part of the surface of the LTCC- board which is occupied by conducting patterns, and thus to increase that part of the surface of the LTCC-board which can be used by components, is to let the board consist of a plurality of layers of LTCC-material, with conducting patterns on top of each layer. Connections between the surface of the board and the various layers of the board is achieved by means of so-called via-holes, i.e. holes in the board material, which have been made conducting by entirely or partially being filled with conducting material.
There is often a desire to connect the circuits on the surface of the board to a capacitance. So as not to use up surface area with a capacitive component, it is possible to deposit plates of conducting material inside the LTCC- board, which plates then form the elements of a capacitance. The elements are connected to the surface of the board using via-holes. An example of letting elements inside an LTCC-board form a capacitance is shown in US 5,144,526. This method provides a good function but can be said to be relatively expensive and complex to manufacture.
SUMMARY OF THE INVENTION:
The main object of the present invention is thus to design a capacitive device in a circuit board, which is simple and inexpensive to manufacture, at the same time as it does not limit the area which can be used to assemble components on.
LTCC-boards often rest on a supporting structure of an electrically conducting material. The reason that the supporting structure is made from an electrically conducting material is that it can then be used to shield the board electrically as well as mechanically.
The object of the invention is achieved by letting the invention use the electrically conducting supporting structure as a first element in the capacitance.
The second element of the capacitance consists of an electrically supporting element arranged in or on the circuit board. A dielectric material is arranged between the circuit board and the electrically conducting supporting structure.
In a preferred embodiment, the circuit board is of the LTCC-kind, and the other element of the capacitance is arranged on that side of the circuit board which faces the electrically conducting supporting structure. Furthermore, the dielectric material between the circuit board and the electrically conducting supporting structure is a dielectric glue, which is also used for joining the circuit board and the electrically conducting supporting structure together. BRIEF DESCRIPTION OF THE DRAWINGS:
The invention will in the following be described using an example of an embodiment, and with reference to the appended drawings, in which:
Fig. 1 is a simplified and enlarged side cross-section through a device according to the invention, and
Fig. 2 is a simplified view of that side of the circuit board which faces the electrically conducting supporting material, in an alternative embodiment of the invention.
PREFERRED EMBODIMENTS: Fig. 1 shows a simplified and enlarged side cross-section through a device 100 according to the invention. As can be seen from the figure, the device 100 comprises a circuit board with a supporting structure 120, preferably made of an LTCC-material. On one side of the supporting structure 120 of the circuit board there is arranged an electrical component 125, and on the other side of the supporting structure 120 there is arranged an electrically conducting element 170. The device 100 furthermore has an electrically conducting supporting structure 130 which, in the example shown, also serves as a ground plane for the device 100.
The electrically conducting supporting structure 130 is separated from the element 170 and the supporting structure 120 by means of a dielectric material 140. In a preferred embodiment, the dielectric material 140 is a dielectric glue, which then serves both to fix the supporting structure 120 relative to the supporting metal 130, and to serve as a dielectric material in the capacitance 150 formed between the element 170 and the electrically conducting supporting structure 130. Thus, a capacitance 150 is formed, in the figure shown with a split arrow between the element 170 and the electrically conducting supporting structure 130. In the example shown, this capacitance 150 is utilized, as can be seen from the figure, in order to capacitively couple a component 125 on the supporting structure 120 to ground, since the other element in the capacitance 150, the electrically conducting supporting structure 130, also serves as ground plane for the device 100.
Furthermore, as can be seen from the figure, the component 125 is connected to the element 170 by means of a conductor 180 and a conductor 190 in a via-hole.
Fig. 2 shows the underside of a supporting structure 220 in an alternative embodiment of the invention. For reasons of simplicity, the electrically conducting supporting metal structure is not shown. The figure shows how a plurality of conducting elements 270 have been arranged on that side of the supporting structure 220 which is to face the supporting metal structure. In this manner, a plurality of capacitances can be formed in the device according to the invention. The capacitances in this embodiment have a common second plate in the (not shown) supporting metal structure. The dots 205 show connecting points for the above-mentioned conductors in the via-holes .
The invention is not limited to the examples of embodiments described above and shown in the drawings, but can be varied in a multitude of ways within the scope of the appended claims. For example, the supporting structure in the circuit board does not of course need to be an LTCC- material, but can be chosen from a large number of materials which are suitable in this context, for example glass-fibre materials or plastic materials. The dielectric material which separates the two elements of the capacitance is, in the example shown, glue, but can of course be any other dielectric material, adhesive or not. The separating dielectric material can, for example, be air, in which case the supporting structure 120 can be fixed in place relative to the electrically conducting support 130 using, for example, isolating distances or grooves in the supporting material.
The second element 170, 270 of the capacitance has throughout been shown arranged on that side of the structure 120, 220 which faces the supporting structure 130, but can of course be positioned for example inside of the structure 120, 220 or on that side which faces away from the supporting structure 130.

Claims

CLAIMS:
1. A capacitive device (100) in a circuit board with at least one supporting structure (120), at least one electrically conducting supporting structure (130) for the circuit board, at least one dielectric layer (140) between the supporting structure and the electrically conducting supporting structure (130), which device has at least one capacitance (150) comprising a first and a second element, c h a r a c t e r i z e d i n that the first element of the capacitance (150) consists of the electrically conducting supporting structure (130), and in that the dielectric material (140) consists of the material used to join the two elements of the capacitance together.
2. Capacitive device according to claim 1, c h a r a c t e r i z e d i n that the second element of the capacitance (150) is arranged on that side of the supporting structure (120) which faces the electrically conducting supporting structure (130).
3. Capacitive device according to claim 1, c h a r a c t e r i z e d i n that the second element of the capacitance is arranged inside the supporting structure (120).
4. Capacitive device according to claim 1, c h a r a c t e r i z e d i n that the second element of the capacitance is arranged on that side of the supporting structure (120) which faces away from the electrically conducting supporting structure (130).
5. Capacitive device according to any one of the previous claims, c h a r a c t e r i z e d i n that the dielectric layer (140) between the supporting structure (120) and the electrically conducting supporting structure (130) consists of a dielectric glue.
6. Capacitive device according to any one of claims 1-4, c h a r a c t e r i z e d i n that the dielectric layer (140) between the supporting structure (120) and the electrically conducting supporting structure (130) consists of air.
7. Capacitive device (100) according to any one of the previous claims, in which device the supporting structure (120) consists of an LTCC-material.
PCT/SE1998/000767 1997-04-30 1998-04-28 Capacitive device on a circuit board WO1998049876A2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU74594/98A AU7459498A (en) 1997-04-30 1998-04-28 Capacitive device on a circuit board

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9701666-1 1997-04-30
SE9701666A SE9701666L (en) 1997-04-30 1997-04-30 Capacitive device on a circuit board

Publications (2)

Publication Number Publication Date
WO1998049876A2 true WO1998049876A2 (en) 1998-11-05
WO1998049876A3 WO1998049876A3 (en) 1999-03-11

Family

ID=20406820

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1998/000767 WO1998049876A2 (en) 1997-04-30 1998-04-28 Capacitive device on a circuit board

Country Status (3)

Country Link
AU (1) AU7459498A (en)
SE (1) SE9701666L (en)
WO (1) WO1998049876A2 (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4967316A (en) * 1988-11-02 1990-10-30 Robert Bosch Gmbh Electric circuit unit

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4967316A (en) * 1988-11-02 1990-10-30 Robert Bosch Gmbh Electric circuit unit

Also Published As

Publication number Publication date
AU7459498A (en) 1998-11-24
SE9701666L (en) 1998-10-31
SE9701666D0 (en) 1997-04-30
WO1998049876A3 (en) 1999-03-11

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