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WO1999033327A1 - Method and arrangement relating to a grounding area on a circuit board - Google Patents

Method and arrangement relating to a grounding area on a circuit board Download PDF

Info

Publication number
WO1999033327A1
WO1999033327A1 PCT/SE1998/002417 SE9802417W WO9933327A1 WO 1999033327 A1 WO1999033327 A1 WO 1999033327A1 SE 9802417 W SE9802417 W SE 9802417W WO 9933327 A1 WO9933327 A1 WO 9933327A1
Authority
WO
WIPO (PCT)
Prior art keywords
recess
ground plane
electrically conductive
area
conductive material
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/SE1998/002417
Other languages
French (fr)
Inventor
Leif Bergstedt
Bo Carlberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
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 AB filed Critical Telefonaktiebolaget LM Ericsson AB
Priority to AU19933/99A priority Critical patent/AU1993399A/en
Publication of WO1999033327A1 publication Critical patent/WO1999033327A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H10W44/20—
    • 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
    • H05K1/0213—Electrical arrangements not otherwise provided for
    • H05K1/0216—Reduction of cross-talk, noise or electromagnetic interference
    • H05K1/0218—Reduction of cross-talk, noise or electromagnetic interference by printed shielding conductors, ground planes or power plane
    • H10W99/00—
    • 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
    • H05K1/0213—Electrical arrangements not otherwise provided for
    • H05K1/0237—High frequency adaptations

Definitions

  • the present invention relates to a grounding area on a circuit board, and also to a method of creating such an area.
  • a frequently occurring requirement in the manufacture of circuit boards is that it is desirable to connect to ground the components that are arranged on or in the circuit board.
  • the components are usually arranged on or in a dielectric material, below which a ground plane may be located.
  • Grounding of components may then be achieved in at least two ways, either by each component being individually connected to the ground plane by means of a connection through the dielectric material on or in which the component is arranged, or by common grounding areas being created on or in the dielectric material, to which grounding areas a number of components can be connected.
  • This invention relates to such a common grounding area, and also to a method of creating such an area.
  • a common way of creating grounding areas on or in a dielectric material on a circuit board is to arrange an area of an electrically conductive material on or in the dielectric material. This area is then connected to the ground plane by means of so-called via-holes, in other words holes that are made in the electrically conductive area, through the dielectric material, and down to the ground plane. The walls of the holes are then plated with an electrically conductive material, by means of which an electrical connection is created between the ground plane and said area of electrically conductive material.
  • One or more components which it is desired to connect to ground can then be connected to the grounding area created in this way.
  • the problem that is solved according to the invention is that of creating a grounding area on or in a circuit board, which grounding area provides a better ground connection than previously known solutions.
  • the grounding area that is created according to the invention constitutes, above all within the microwave range, an essentially homogeneous ground connection without inductances.
  • said body will appear to be a homogeneous body of electrically conductive material, the result of which is that essentially no inductances will be exhibited.
  • Fig. 1 shows diagrammatically from above a starting blank for creating a grounding area according to the invention
  • Figs 2 and 3 show diagrammatically from above the starting blank in Fig. 1 in a later step of a method according to the invention
  • Fig. 4 shows an arrangement according to the invention, seen from the side, and
  • Fig. 5 shows the arrangement in Fig. 3 in the section along V-V.
  • PREFERRED EMBODIMENT Fig. 1 shows diagrammatically from above a starting blank 10 for creating a grounding area according to the invention.
  • the starting blank 10 comprises a ground plane (not shown), a layer of a dielectric material 20 arranged on top of this ground plane, and also an area 30 of an electrically conductive material, which is arranged on top of the dielectric material 20.
  • dielectric material use may be made of an organic or inorganic material with desirable dielectric properties. Ceramic material may be cited as an example of an inorganic material, and Teflon material may be cited as an example of an organic material.
  • a continuous recess is created in the area of electrically conductive material, which recess extends through the dielectric material and down to the ground plane. This is shown in Fig. 2, where the starting blank 10 of Fig. 1 is shown with a rectangular recess 40.
  • the recess may of course have other geometrical shapes, for example a circle, but should form a continuous contour.
  • the recess may be created in a great many ways well-known to the person skilled in the art, which will not be described in greater detail here. However, laser machining, etching and mechanical working such as, for example, milling may be cited as examples of methods of creating recesses.
  • the recess 40 After the recess 40 has been created, it is filled with an electrically conductive material 50 which is shown in Fig. 3. As the recess forms a closed contour, a body of dielectric material enclosed by electrically conductive material is thus created.
  • This body 80 can be seen in Fig. 4 which shows the resulting circuit board seen from the side, and in Fig. 5 which shows the resulting circuit board seen from the side along the section line V-V in Fig. 3.
  • the recess 40 is filled with electrically conductive material 50, this is preferably carried out by means of plating and, in a preferred embodiment, the electrically conductive material 50 is copper.
  • the so-called ratio rule should be followed, which means that the width of the recess should at least be the same as the depth of the recess.
  • the copper-enclosed body 80 of dielectric material that is created according to the method will appear, above all to signals at higher frequencies, for example the microwave range, to be a homogeneous body of electrically conductive material.
  • the result of this is that, if the body 80 is used as a grounding area, this grounding area will be essentially free from inductances.
  • this area should be dimensioned so that in every respect it essentially corresponds to the dimensions of the pins, "the legs", of the components that it is desired to connect to the area 30.
  • the invention is not limited to the embodiments that have been described above, but may be varied freely within the scope of the patent claims below.
  • the recess may be made and also the plating may be carried out using on the whole arbitrarily selected methods, if the conditions indicated above for the recess and the plating respectively are observed.
  • the recess it is entirely possible for the recess to be made and the plating of the recess to be carried out only in the dielectric, before the electrically conductive area is arranged on the dielectric.
  • a suitably dimensioned and filled recess, on top of which an area of electrically conductive material is arranged, will then form the body that has been described above.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Structure Of Printed Boards (AREA)

Abstract

The invention relates to a method of creating a grounding area on a circuit board, which circuit board comprises a ground plane (60) and also a dielectric substrate (20) located on top of this ground plane (60). The method is characterized by arranging an area (30) of an electrically conductive material on that side of the dielectric substrate (20) which faces away from the ground plane (60), creating a recess (40) in the dielectric material (20), which recess forms a closed contour and connects the area (30) of electrically conductive material to the ground plane (60), and filling the recess (40) with an electrically conductive material (50). The invention also relates to such an arrangement for ground connection on a circuit board.

Description

TITLE
Method and arrangement relating to a grounding area on a circuit board.
TECHNICAL FIELD The present invention relates to a grounding area on a circuit board, and also to a method of creating such an area.
STATE OF THE ART A frequently occurring requirement in the manufacture of circuit boards is that it is desirable to connect to ground the components that are arranged on or in the circuit board. The components are usually arranged on or in a dielectric material, below which a ground plane may be located.
Grounding of components may then be achieved in at least two ways, either by each component being individually connected to the ground plane by means of a connection through the dielectric material on or in which the component is arranged, or by common grounding areas being created on or in the dielectric material, to which grounding areas a number of components can be connected. This invention relates to such a common grounding area, and also to a method of creating such an area.
A common way of creating grounding areas on or in a dielectric material on a circuit board is to arrange an area of an electrically conductive material on or in the dielectric material. This area is then connected to the ground plane by means of so-called via-holes, in other words holes that are made in the electrically conductive area, through the dielectric material, and down to the ground plane. The walls of the holes are then plated with an electrically conductive material, by means of which an electrical connection is created between the ground plane and said area of electrically conductive material. One or more components which it is desired to connect to ground can then be connected to the grounding area created in this way.
One problem of this type of common grounding area is that the via-holes exhibit inductances, which means that the via-holes will function as filters which filter out or attenuate signals at certain frequencies.
A previously known arrangement for creating improved properties of ground connections in a circuit board is disclosed in US 5 401 912. This arrangement exhibits a screen around a via-hole. The arrangement would appear to be incapable of providing complete screening, and also appears to increase the complexity involved in manufacturing the circuit board.
SUMMARY OF THE INVENTION
The problem that is solved according to the invention is that of creating a grounding area on or in a circuit board, which grounding area provides a better ground connection than previously known solutions. The grounding area that is created according to the invention constitutes, above all within the microwave range, an essentially homogeneous ground connection without inductances.
This problem is solved by virtue of the fact that, starting from a circuit board comprising a ground plane and also a dielectric substrate located on top of this ground plane, an area of an electrically conductive material is arranged in the dielectric substrate or on that side of the dielectric substrate which faces away from the ground plane. Subsequently, a recess is created in said area of electrically conductive material, which recess forms a closed contour and extends through the dielectric material down to the ground plane. The recess is filled with an electrically conductive material, by means of which a body of dielectric material is obtained, which is entirely enclosed by electrically conductive material.
To signals in higher frequency ranges, for example within the microwave range, said body will appear to be a homogeneous body of electrically conductive material, the result of which is that essentially no inductances will be exhibited.
DESCRIPTION OF THE DRAWINGS
The invention will be described in greater detail below with the aid of an example of a preferred embodiment, and with the aid of the appended drawings, in which
Fig. 1 shows diagrammatically from above a starting blank for creating a grounding area according to the invention,
Figs 2 and 3 show diagrammatically from above the starting blank in Fig. 1 in a later step of a method according to the invention,
Fig. 4 shows an arrangement according to the invention, seen from the side, and
Fig. 5 shows the arrangement in Fig. 3 in the section along V-V.
PREFERRED EMBODIMENT Fig. 1 shows diagrammatically from above a starting blank 10 for creating a grounding area according to the invention. The starting blank 10 comprises a ground plane (not shown), a layer of a dielectric material 20 arranged on top of this ground plane, and also an area 30 of an electrically conductive material, which is arranged on top of the dielectric material 20.
As dielectric material, use may be made of an organic or inorganic material with desirable dielectric properties. Ceramic material may be cited as an example of an inorganic material, and Teflon material may be cited as an example of an organic material.
According to the invention, a continuous recess is created in the area of electrically conductive material, which recess extends through the dielectric material and down to the ground plane. This is shown in Fig. 2, where the starting blank 10 of Fig. 1 is shown with a rectangular recess 40. The recess may of course have other geometrical shapes, for example a circle, but should form a continuous contour.
The recess may be created in a great many ways well-known to the person skilled in the art, which will not be described in greater detail here. However, laser machining, etching and mechanical working such as, for example, milling may be cited as examples of methods of creating recesses.
After the recess 40 has been created, it is filled with an electrically conductive material 50 which is shown in Fig. 3. As the recess forms a closed contour, a body of dielectric material enclosed by electrically conductive material is thus created.
This body 80 can be seen in Fig. 4 which shows the resulting circuit board seen from the side, and in Fig. 5 which shows the resulting circuit board seen from the side along the section line V-V in Fig. 3.
When the recess 40 is filled with electrically conductive material 50, this is preferably carried out by means of plating and, in a preferred embodiment, the electrically conductive material 50 is copper. As far as the dimensions of the recess 40 are concerned, the so-called ratio rule should be followed, which means that the width of the recess should at least be the same as the depth of the recess.
The copper-enclosed body 80 of dielectric material that is created according to the method will appear, above all to signals at higher frequencies, for example the microwave range, to be a homogeneous body of electrically conductive material. The result of this is that, if the body 80 is used as a grounding area, this grounding area will be essentially free from inductances.
As far as the dimensioning of the area 30 of electrically conductive material is concerned, this area should be dimensioned so that in every respect it essentially corresponds to the dimensions of the pins, "the legs", of the components that it is desired to connect to the area 30.
The invention is not limited to the embodiments that have been described above, but may be varied freely within the scope of the patent claims below. For example, the recess may be made and also the plating may be carried out using on the whole arbitrarily selected methods, if the conditions indicated above for the recess and the plating respectively are observed.
Furthermore, it is entirely possible for the recess to be made and the plating of the recess to be carried out only in the dielectric, before the electrically conductive area is arranged on the dielectric. A suitably dimensioned and filled recess, on top of which an area of electrically conductive material is arranged, will then form the body that has been described above.

Claims

1. Method of creating a grounding area on a circuit board, which circuit board comprises a ground plane (60) and also a dielectric substrate (20) located on top of this ground plane (60), which method is c h a r a c t e r i z e d i n that it comprises the following steps: an area (30) of an electrically conductive material is arranged on that side of the dielectric substrate (20) which faces away from the ground plane (60), a recess (40) is created in the dielectric material
(20), which recess forms a closed contour and connects the area (30) of electrically conductive material to the ground plane (60), - the recess (40) is filled with an electrically conductive material (50).
2. Method according to claim 1, according to which the recess (40) is made by means of a laser.
3. Method according to claim 1, according to which the recess (40) is made by means of etching.
4. Method according to claim 1, according to which the recess (40) is made by means of mechanical working.
5. Method according to any one of the preceding claims, according to which the closed contour formed by the recess (40) is a rectangle.
6. Method according to any one of the preceding claims, according to which the closed contour formed by the recess (40) is a circle.
7. Method according to any one of the preceding claims, according to which the recess (40) is made to be at least as wide as the depth of the recess (40).
8. Arrangement for ground connection on a circuit board, which circuit board comprises a ground plane (60) and also a dielectric substrate (20) located on top of this ground plane (60), c h a r a c t e r i z e d i n that it comprises: - a first area (30) of an electrically conductive material on that side of the dielectric substrate (20) which faces away from the ground plane (60), a recess (40) in the dielectric material (20), which recess (40) is filled with electrically conductive material (50), forms a closed contour and connects the first area (30) of electrically conductive material to the ground plane (60).
9. Arrangement according to claim 8, c h a r a c t e r i z e d i n that the closed contour formed by the recess (40) is a rectangle.
10. Arrangement according to claim 8, c h a r a c t e r i z e d i n that the closed contour formed by the recess (40) is a circle.
11. Arrangement according to any one of the preceding claims, c h a r a c t e r i z e d i n that the width of the recess (40) is at least the same as its depth.
PCT/SE1998/002417 1997-12-23 1998-12-22 Method and arrangement relating to a grounding area on a circuit board Ceased WO1999033327A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU19933/99A AU1993399A (en) 1997-12-23 1998-12-22 Method and arrangement relating to a grounding area on a circuit board

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9704862A SE511144C2 (en) 1997-12-23 1997-12-23 Method and apparatus for a grounding surface on a circuit board
SE9704862-3 1997-12-23

Publications (1)

Publication Number Publication Date
WO1999033327A1 true WO1999033327A1 (en) 1999-07-01

Family

ID=20409564

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1998/002417 Ceased WO1999033327A1 (en) 1997-12-23 1998-12-22 Method and arrangement relating to a grounding area on a circuit board

Country Status (3)

Country Link
AU (1) AU1993399A (en)
SE (1) SE511144C2 (en)
WO (1) WO1999033327A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5401912A (en) * 1993-06-07 1995-03-28 St Microwave Corp., Arizona Operations Microwave surface mount package
US5448020A (en) * 1993-12-17 1995-09-05 Pendse; Rajendra D. System and method for forming a controlled impedance flex circuit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5401912A (en) * 1993-06-07 1995-03-28 St Microwave Corp., Arizona Operations Microwave surface mount package
US5522132A (en) * 1993-06-07 1996-06-04 St Microwave Corp., Arizona Operations Microwave surface mount package
US5448020A (en) * 1993-12-17 1995-09-05 Pendse; Rajendra D. System and method for forming a controlled impedance flex circuit

Also Published As

Publication number Publication date
SE9704862D0 (en) 1997-12-23
SE511144C2 (en) 1999-08-09
AU1993399A (en) 1999-07-12
SE9704862L (en) 1999-06-24

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