CA1196731A - Process and device for the manufacture of printed circuit boards - Google Patents
Process and device for the manufacture of printed circuit boardsInfo
- Publication number
- CA1196731A CA1196731A CA000428115A CA428115A CA1196731A CA 1196731 A CA1196731 A CA 1196731A CA 000428115 A CA000428115 A CA 000428115A CA 428115 A CA428115 A CA 428115A CA 1196731 A CA1196731 A CA 1196731A
- Authority
- CA
- Canada
- Prior art keywords
- holes
- foil
- base material
- screen
- screen printing
- 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.)
- Expired
Links
- 238000000034 method Methods 0.000 title claims abstract description 36
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 10
- 239000000463 material Substances 0.000 claims abstract description 43
- 239000011888 foil Substances 0.000 claims abstract description 33
- 229910052751 metal Inorganic materials 0.000 claims abstract description 29
- 239000002184 metal Substances 0.000 claims abstract description 29
- 238000007650 screen-printing Methods 0.000 claims abstract description 29
- 230000000873 masking effect Effects 0.000 claims abstract description 11
- 238000005530 etching Methods 0.000 claims abstract description 8
- 238000001035 drying Methods 0.000 claims abstract description 4
- 239000004033 plastic Substances 0.000 claims abstract description 4
- 239000002904 solvent Substances 0.000 claims abstract description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 27
- 229910052802 copper Inorganic materials 0.000 claims description 22
- 239000010949 copper Substances 0.000 claims description 22
- 239000000203 mixture Substances 0.000 claims description 14
- 238000000151 deposition Methods 0.000 claims description 9
- 239000000853 adhesive Substances 0.000 claims description 3
- 230000001070 adhesive effect Effects 0.000 claims description 3
- 229910052782 aluminium Inorganic materials 0.000 claims description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 3
- 238000005553 drilling Methods 0.000 claims description 3
- 230000000875 corresponding effect Effects 0.000 claims 3
- 238000005429 filling process Methods 0.000 claims 1
- 239000004020 conductor Substances 0.000 abstract description 8
- 239000010410 layer Substances 0.000 description 18
- 230000008021 deposition Effects 0.000 description 6
- 239000011889 copper foil Substances 0.000 description 4
- 238000009713 electroplating Methods 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- 239000012790 adhesive layer Substances 0.000 description 2
- 238000000454 electroless metal deposition Methods 0.000 description 2
- 239000003822 epoxy resin Substances 0.000 description 2
- 229920002120 photoresistant polymer Polymers 0.000 description 2
- 229920000647 polyepoxide Polymers 0.000 description 2
- 238000007639 printing Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- XSTXAVWGXDQKEL-UHFFFAOYSA-N Trichloroethylene Chemical group ClC=C(Cl)Cl XSTXAVWGXDQKEL-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000007605 air drying Methods 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 238000013007 heat curing Methods 0.000 description 1
- 235000021190 leftovers Nutrition 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- WXHIJDCHNDBCNY-UHFFFAOYSA-N palladium dihydride Chemical compound [PdH2] WXHIJDCHNDBCNY-UHFFFAOYSA-N 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000003678 scratch resistant effect Effects 0.000 description 1
- 229960002668 sodium chloride Drugs 0.000 description 1
- 235000002639 sodium chloride Nutrition 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- CMXPERZAMAQXSF-UHFFFAOYSA-M sodium;1,4-bis(2-ethylhexoxy)-1,4-dioxobutane-2-sulfonate;1,8-dihydroxyanthracene-9,10-dione Chemical compound [Na+].O=C1C2=CC=CC(O)=C2C(=O)C2=C1C=CC=C2O.CCCCC(CC)COC(=O)CC(S([O-])(=O)=O)C(=O)OCC(CC)CCCC CMXPERZAMAQXSF-UHFFFAOYSA-M 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/0094—Filling or covering plated through-holes or blind plated vias, e.g. for masking or for mechanical reinforcement
-
- 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
- H05K2201/095—Conductive through-holes or vias
- H05K2201/0959—Plated through-holes or plated blind vias filled with insulating material
-
- 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
- H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
- H05K2203/07—Treatments involving liquids, e.g. plating, rinsing
- H05K2203/0756—Uses of liquids, e.g. rinsing, coating, dissolving
- H05K2203/0769—Dissolving insulating materials, e.g. coatings, not used for developing resist after exposure
-
- 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
- H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
- H05K3/06—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed chemically or electrolytically, e.g. by photo-etch process
- H05K3/061—Etching masks
-
- 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
- H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
- H05K3/12—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using thick film techniques, e.g. printing techniques to apply the conductive material or similar techniques for applying conductive paste or ink patterns
- H05K3/1216—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern using thick film techniques, e.g. printing techniques to apply the conductive material or similar techniques for applying conductive paste or ink patterns by screen printing or stencil printing
-
- 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
- H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
- H05K3/42—Plated through-holes or plated via connections
- H05K3/425—Plated through-holes or plated via connections characterised by the sequence of steps for plating the through-holes or via connections in relation to the conductive pattern
- H05K3/427—Plated through-holes or plated via connections characterised by the sequence of steps for plating the through-holes or via connections in relation to the conductive pattern initial plating of through-holes in metal-clad substrates
Abstract
Abstract The process and device in accordance with the present in-vention allow the simple and economic manufacture of printed circuit boards, wherein the metal of the con-ductors as well as the one covering the hole walls is identical with the metal being etched away from the areas between the conductors.
According to this process, a one-or two-sided metal-coated base material is used which, upon production of the hole pattern, is provided in a known manner with a metal layer of desired thickness, said layer covering the surface of the metal foil as well as the hole walls. Subsequently, a masking layer is applied by screen printing a positive image of the desired circuit pattern on the surface(s).
In the following process step, the holes are filled with an ink by means of a screen printing stencil. In accordance with one embodiment of the invention, the ink used forms an etch-resistant surface film when drying. Upon etching, the masking layer as well as the surface film and the hole fillings are removed with a suitable solvent.
The screen printing stencil comprises a carrier screen fixed to a frame, said carrier screen being provided on its side facing the surface to be printed with a metal or plastic foil, said screen and foil being provided with holes at locations in proportion to the hole pattern in the base material.
According to this process, a one-or two-sided metal-coated base material is used which, upon production of the hole pattern, is provided in a known manner with a metal layer of desired thickness, said layer covering the surface of the metal foil as well as the hole walls. Subsequently, a masking layer is applied by screen printing a positive image of the desired circuit pattern on the surface(s).
In the following process step, the holes are filled with an ink by means of a screen printing stencil. In accordance with one embodiment of the invention, the ink used forms an etch-resistant surface film when drying. Upon etching, the masking layer as well as the surface film and the hole fillings are removed with a suitable solvent.
The screen printing stencil comprises a carrier screen fixed to a frame, said carrier screen being provided on its side facing the surface to be printed with a metal or plastic foil, said screen and foil being provided with holes at locations in proportion to the hole pattern in the base material.
Description
;
3~
1 The present invention relates to a process for the manu-
3~
1 The present invention relates to a process for the manu-
2 facture of p~inted circuit boards provided wi~h holes havlng
3 metallized walls and, particularly, to such boards provided
4 with copper conduc~ors and coppe~-~plaeed hole ~al}s.
6 For manufacturing such printed circuit boards, a number of 7 processes have been suggested. In one of ~hose processes the 8 conductors as well as the hole walls are provided with a 9 metal layer serving as an etch-resist during the subsequent etching step and being removed afterwards. Preferred metsls 11 or metal alloys to be used as etch-resistant metal layers are 12 such metals which can easily be removed without adversely 13 affecting the copper surface as, for example, tin or tin/lead 14 alloys.
16 Independent of the poor economy of such process, its high 17 reject rates, too, make it unsuitable for mass production;
18 especially, it has proven to be difficult to achieve a copper 19 surface with good solderability.
21 Furthermore, it has been suggested - for two-sided copper clad 22 boards - to provide the holes in a first step and, subsequently, 23 to deposit copper on the hole walls by electroless copper 24 deposition or by electroless copper deposition followed by 2S electroplating until a desired thickness of the copper layer 26 on the hole walls and the surface of the base material is 27 achieved. Subsequently, the surface of the base material i~
2B covered on both sides with a photoresist dry film of suitsble 29 thickness. ~pon exposure through a positive of ~he desired printed circuit pattern and developing, an etch-resistant mask 31 is formed which, on the one hand, covers the copper surface 32 corresponding to ~he desire~ circuit pattern and, on the other _ .~
~1~6~3~
1 hand, the holes thereby sealing them hermetically. The copper 2 in the exposed areas is removed in a subsequent etching step.
3 After re~oval of the masking layer, the circuit board shows 4 copper conductors and copper-clad hole walls well suited for soldering.
7 The high costs of suitable photoresist dry films and the 8 photoprinting process itself constitute a considerable dis~
9 advantage of this process whenever conductor width and density would allowscreen printing methods.
12 Thereforf, it nas been suggested, instead of using a photo-13 resist dry film, to fill the holes with an etch-resistant ink 14 using, for example, a squeegee. Before or after the removal of the said ink from the surface, the ink inside the holes 16 is hardened by heat curing. Subsequently, an etch-resistant 17 mask corresponding to the positive of the conductor pattern is 18 applied by screen printing. After etching, the said etch-19 resistant mask as well as the hole filIings have to be removed.
The removal of the dried and hardened ink from the surf~ce 21 prior to screen printing has prsven to be a very tedious 22 process, normally to be performed by precision polishing.
23 Furthermore, it has also proven to be costly and difficult to 24 remove all hole-fill left overs fro~ the hole walls after etching. Therefore, this process is not suited for mass 26 production purposes as it requires very ~horoughful 27 processing to achieve acceptable reject ~a~es.
29 The process in accordance with the present i~vention avoids the problems and disadvanta~es described hereinabove and pro-3~
595-RG-0.
1 vides a safe and economic process for producing printed 2 circuit boards with copper conductors and coppPr-clad hole 3 walls.
In accordance with the present invention there is provlded 6 a process for the manufacture of printed circuit boards with 7 metallized hole walls on any suitable insulating base 8 material provided on one or both sides with a metal layer ~ comprising the steps of providing said base material with those holes whose walls are metal-coated in the finished circuit 11 board, and depositing a metal layer of desired thickness 12 on the walls of said holes and thP surface or selected areas 13 of the surface of said base material in known manner, 14 characterized in that a masking layer is applied to said metal-coated surface(s~ of said base material by screen 16 printing a positive image of the desired circuit pattern;
17 and that said holes provided with metallized walls are sub-18 sequently filled with a resinous ink composition employing 19 a screen printing stencil provided on the side facing the surface of said base material during use with a foil securely 21 fixed to the screen of said stencil; and that said screen and 22 said foil are provided with holes at locations corresponding 23 to the holes with metallized walls in the circuit pattern;
24 and that said resinous ink composition is pressed into the holes of said base material by means of a squeegee; and that 26 the unmasked areas of the metal layer on the surface of said 27 base material are etched away in known ~anner; and, finally, 28 that the masking layer applied by screen printing and the said 29 ink composition in said holes are removed by the agency of one or more suitable solvents.
673~
1 A metal-clad base material, for example a two-sided copper-2 clad insulating base like, e.g., a laminate, hereinafter 3 called base material, of suitable size, is provided with holes 4 to be coated with a metal layer. Subsequently, a eopper layer of desired thickness is deposited in a well known manner 6 on the surface of the base material and the hole walls.
7 Then, a masking layer corresponding to the desired printed 8 circuit pattern is screen printed onto the base material, 9 preferably using a scratch-resistant screen printing ink which is hardenable by W radiation. Subsequently, the holes are 11 filled with an etch-resistant ma,erial using a screen printing 12 s~encil in accordance with the present invention, said stencil 13 being manufactured by fixing a suitable screen in a frame, 14 said screen being provided on the side facing the surface to be printed with a foil of metal or plastic material of 16 a thickness of Q,1 mm or less. In accordance with one l? e~bodiment of the present invention an aluminum foil is fixed 18 to the screen by means of an adhesive.
~
Screen and foil are provided with holes, preferably by drilling, 21 in a pattern which corresponds to the hole pattern of the 22 finished circuit board. Preferably, the diameter of the 23 holes in the screen and foil is larger than the diameter of 24 the holes in the base material, but should not exceed the limit of the etch-resistant mask applied by screen printing.
26 As a rule, the diameter of the holes in the screen and foil 27 is only slightly in excess of the diameter of the holes in 28 the base material.
2~ ' ~ 4
6 For manufacturing such printed circuit boards, a number of 7 processes have been suggested. In one of ~hose processes the 8 conductors as well as the hole walls are provided with a 9 metal layer serving as an etch-resist during the subsequent etching step and being removed afterwards. Preferred metsls 11 or metal alloys to be used as etch-resistant metal layers are 12 such metals which can easily be removed without adversely 13 affecting the copper surface as, for example, tin or tin/lead 14 alloys.
16 Independent of the poor economy of such process, its high 17 reject rates, too, make it unsuitable for mass production;
18 especially, it has proven to be difficult to achieve a copper 19 surface with good solderability.
21 Furthermore, it has been suggested - for two-sided copper clad 22 boards - to provide the holes in a first step and, subsequently, 23 to deposit copper on the hole walls by electroless copper 24 deposition or by electroless copper deposition followed by 2S electroplating until a desired thickness of the copper layer 26 on the hole walls and the surface of the base material is 27 achieved. Subsequently, the surface of the base material i~
2B covered on both sides with a photoresist dry film of suitsble 29 thickness. ~pon exposure through a positive of ~he desired printed circuit pattern and developing, an etch-resistant mask 31 is formed which, on the one hand, covers the copper surface 32 corresponding to ~he desire~ circuit pattern and, on the other _ .~
~1~6~3~
1 hand, the holes thereby sealing them hermetically. The copper 2 in the exposed areas is removed in a subsequent etching step.
3 After re~oval of the masking layer, the circuit board shows 4 copper conductors and copper-clad hole walls well suited for soldering.
7 The high costs of suitable photoresist dry films and the 8 photoprinting process itself constitute a considerable dis~
9 advantage of this process whenever conductor width and density would allowscreen printing methods.
12 Thereforf, it nas been suggested, instead of using a photo-13 resist dry film, to fill the holes with an etch-resistant ink 14 using, for example, a squeegee. Before or after the removal of the said ink from the surface, the ink inside the holes 16 is hardened by heat curing. Subsequently, an etch-resistant 17 mask corresponding to the positive of the conductor pattern is 18 applied by screen printing. After etching, the said etch-19 resistant mask as well as the hole filIings have to be removed.
The removal of the dried and hardened ink from the surf~ce 21 prior to screen printing has prsven to be a very tedious 22 process, normally to be performed by precision polishing.
23 Furthermore, it has also proven to be costly and difficult to 24 remove all hole-fill left overs fro~ the hole walls after etching. Therefore, this process is not suited for mass 26 production purposes as it requires very ~horoughful 27 processing to achieve acceptable reject ~a~es.
29 The process in accordance with the present i~vention avoids the problems and disadvanta~es described hereinabove and pro-3~
595-RG-0.
1 vides a safe and economic process for producing printed 2 circuit boards with copper conductors and coppPr-clad hole 3 walls.
In accordance with the present invention there is provlded 6 a process for the manufacture of printed circuit boards with 7 metallized hole walls on any suitable insulating base 8 material provided on one or both sides with a metal layer ~ comprising the steps of providing said base material with those holes whose walls are metal-coated in the finished circuit 11 board, and depositing a metal layer of desired thickness 12 on the walls of said holes and thP surface or selected areas 13 of the surface of said base material in known manner, 14 characterized in that a masking layer is applied to said metal-coated surface(s~ of said base material by screen 16 printing a positive image of the desired circuit pattern;
17 and that said holes provided with metallized walls are sub-18 sequently filled with a resinous ink composition employing 19 a screen printing stencil provided on the side facing the surface of said base material during use with a foil securely 21 fixed to the screen of said stencil; and that said screen and 22 said foil are provided with holes at locations corresponding 23 to the holes with metallized walls in the circuit pattern;
24 and that said resinous ink composition is pressed into the holes of said base material by means of a squeegee; and that 26 the unmasked areas of the metal layer on the surface of said 27 base material are etched away in known ~anner; and, finally, 28 that the masking layer applied by screen printing and the said 29 ink composition in said holes are removed by the agency of one or more suitable solvents.
673~
1 A metal-clad base material, for example a two-sided copper-2 clad insulating base like, e.g., a laminate, hereinafter 3 called base material, of suitable size, is provided with holes 4 to be coated with a metal layer. Subsequently, a eopper layer of desired thickness is deposited in a well known manner 6 on the surface of the base material and the hole walls.
7 Then, a masking layer corresponding to the desired printed 8 circuit pattern is screen printed onto the base material, 9 preferably using a scratch-resistant screen printing ink which is hardenable by W radiation. Subsequently, the holes are 11 filled with an etch-resistant ma,erial using a screen printing 12 s~encil in accordance with the present invention, said stencil 13 being manufactured by fixing a suitable screen in a frame, 14 said screen being provided on the side facing the surface to be printed with a foil of metal or plastic material of 16 a thickness of Q,1 mm or less. In accordance with one l? e~bodiment of the present invention an aluminum foil is fixed 18 to the screen by means of an adhesive.
~
Screen and foil are provided with holes, preferably by drilling, 21 in a pattern which corresponds to the hole pattern of the 22 finished circuit board. Preferably, the diameter of the 23 holes in the screen and foil is larger than the diameter of 24 the holes in the base material, but should not exceed the limit of the etch-resistant mask applied by screen printing.
26 As a rule, the diameter of the holes in the screen and foil 27 is only slightly in excess of the diameter of the holes in 28 the base material.
2~ ' ~ 4
5 95 -RG- 0~ 6733L
1 In a further screen printing step, the ink for protecting the 2 hole walls is pressed into the holes through ehe screen by 3 means of a squeegee. Preferably, a protective ink is used 4 which - under the influence of dry air and the oxygen contained S therein - forms an etch-resistant surface film covering the
1 In a further screen printing step, the ink for protecting the 2 hole walls is pressed into the holes through ehe screen by 3 means of a squeegee. Preferably, a protective ink is used 4 which - under the influence of dry air and the oxygen contained S therein - forms an etch-resistant surface film covering the
6 holes, while the ink inside the holes remains almost or
7 completely viscous. Thereby, the removal of the hole filling
8 in a later process step is easily achievable using a solven~
9 or a thinner fs~ the respective ink.
10 '
11 For a better understanding of the scope of the invention,-
12 referenc~ is made to the following description of the drawings.
13
14 Figures lA to lF show in a diagrammatic view the base material during the different process steps of the process in accordance 16 with the invention.
18 Fig. lA shows a partial view of the base material 1 covered 19 on both sides with a copper foil 2. The walls of the holes 10 as well as the surface of th~ copper foil 2 are provided 21 with a copper layer 3 deposited by methods well kno~m in the art.
23 Fig. lB is the partial view of the board of Fig. lA after 24 applying an etch-resistant mask 4 by screen printing.
26 Fig. lC is a diagrammatic view of the screen printing stencil 27 5 with the holes 9 in proportion to the holes 10 of the base 28 material 1. The screen printing stencil 5 comprises the 29 carrier screen 50 and the thereto adhered stencil foil 51.
The hole 9 is already filled with the ink 7 by means of the 31 squeegee 60 595-RG-0' ~ 731 1 Fig. 1~ shows the board 1 with the hole 10 filled with the 2 ink 7.
4 Fig. lE shows the board of Fig. lD after drying; the viscous-fluid ink filling 7 of hole 10 is covered by an etch-resistant 6 film 70 formed on the surface of the filling 7.
8 Fig. lF shows the finlshed printed circuit board in accordance 9 with the present invention after removalof the etch-resistant mask 4 (Fig. 1~) and the ink filling 7 including ~he film 70 11 from the hole 10. The copper conductors as well as the copper 12 layer on the hole walls is of excellent solderability.
14 The present invention is neither limited to copper-clad base material nor to copperized hole walls. Furthermore, the 16 metal layer on the surface of the insulating base material 17 has not necessarily to be a laminated copper foil~ but can 18 be produced by electroless metal deposition as well as 19 electroless metal deposition followed by electroplating.
21 The scope of the invention will be still better understood 22 from the following examples.
24 Exa~ple 1 The base material used in this example is a glassfiber re-26 inforced epoxy resin laminate provided on both sides with a 27 35 ~m thick copper foil. After the boards are cut to size, 28 the manufacturing process comprises the followlng steps:
595-RG-05~ 37~DIL
., 1 (1) Providing those holes in the base material 2 whose walls are to be metallized;
4 (2) Brushing to remove the burr surrounding the hole wall edges;
7 (3) Cleaning with a cleaner condi~ioner at 70C
for 5 minutes;
(4) Rinsing with water at 50C for 5 minutes;
11 t5) Slightly etching the copper foil surfare 12 ` with a solution of ammoniumpersulf~te at 50C
13 for 1 minute;
(6) Carefully rinsing in wate~;
17 (7) Immersing into a sodiumchloride preca~alysing 18 solution;
(8) Catalysing by immersing into a Sn(II)Pd(II)C1 catalysing solution at room temperature for 21 2 minutes;
23 ~9) Rinsing;
(10) Immersing into a commercially available elec~ro-2fi less copper deposition bath at roo~ temperature ~7 for 45 minutes;
29 tll) Building-up the copper layer on the hole wall to 35 ~m by electroplating~
3~
1 (12) Rinsing and drying;
3 (13) Applying ~he etch-resistant mask corresponding 4 to the desired circuit pattern by screen printing and air dry;
7 (14) Filling the holes by screen printing using the 8 same ink as in step (13) and a screen printing g stencil comprising a screen having adherPd to its lower suriace an aluminum foil of 11 0,8 mm thickness. The screen and the foil 12 are provided with holes corresponding to the 13 pattern of the finished board consisting of 14 holes with metallized walls;
18 Fig. lA shows a partial view of the base material 1 covered 19 on both sides with a copper foil 2. The walls of the holes 10 as well as the surface of th~ copper foil 2 are provided 21 with a copper layer 3 deposited by methods well kno~m in the art.
23 Fig. lB is the partial view of the board of Fig. lA after 24 applying an etch-resistant mask 4 by screen printing.
26 Fig. lC is a diagrammatic view of the screen printing stencil 27 5 with the holes 9 in proportion to the holes 10 of the base 28 material 1. The screen printing stencil 5 comprises the 29 carrier screen 50 and the thereto adhered stencil foil 51.
The hole 9 is already filled with the ink 7 by means of the 31 squeegee 60 595-RG-0' ~ 731 1 Fig. 1~ shows the board 1 with the hole 10 filled with the 2 ink 7.
4 Fig. lE shows the board of Fig. lD after drying; the viscous-fluid ink filling 7 of hole 10 is covered by an etch-resistant 6 film 70 formed on the surface of the filling 7.
8 Fig. lF shows the finlshed printed circuit board in accordance 9 with the present invention after removalof the etch-resistant mask 4 (Fig. 1~) and the ink filling 7 including ~he film 70 11 from the hole 10. The copper conductors as well as the copper 12 layer on the hole walls is of excellent solderability.
14 The present invention is neither limited to copper-clad base material nor to copperized hole walls. Furthermore, the 16 metal layer on the surface of the insulating base material 17 has not necessarily to be a laminated copper foil~ but can 18 be produced by electroless metal deposition as well as 19 electroless metal deposition followed by electroplating.
21 The scope of the invention will be still better understood 22 from the following examples.
24 Exa~ple 1 The base material used in this example is a glassfiber re-26 inforced epoxy resin laminate provided on both sides with a 27 35 ~m thick copper foil. After the boards are cut to size, 28 the manufacturing process comprises the followlng steps:
595-RG-05~ 37~DIL
., 1 (1) Providing those holes in the base material 2 whose walls are to be metallized;
4 (2) Brushing to remove the burr surrounding the hole wall edges;
7 (3) Cleaning with a cleaner condi~ioner at 70C
for 5 minutes;
(4) Rinsing with water at 50C for 5 minutes;
11 t5) Slightly etching the copper foil surfare 12 ` with a solution of ammoniumpersulf~te at 50C
13 for 1 minute;
(6) Carefully rinsing in wate~;
17 (7) Immersing into a sodiumchloride preca~alysing 18 solution;
(8) Catalysing by immersing into a Sn(II)Pd(II)C1 catalysing solution at room temperature for 21 2 minutes;
23 ~9) Rinsing;
(10) Immersing into a commercially available elec~ro-2fi less copper deposition bath at roo~ temperature ~7 for 45 minutes;
29 tll) Building-up the copper layer on the hole wall to 35 ~m by electroplating~
3~
1 (12) Rinsing and drying;
3 (13) Applying ~he etch-resistant mask corresponding 4 to the desired circuit pattern by screen printing and air dry;
7 (14) Filling the holes by screen printing using the 8 same ink as in step (13) and a screen printing g stencil comprising a screen having adherPd to its lower suriace an aluminum foil of 11 0,8 mm thickness. The screen and the foil 12 are provided with holes corresponding to the 13 pattern of the finished board consisting of 14 holes with metallized walls;
(15) Air-drying to form an etch-resistant film
16
17 sealing the hole fillings;
18 (16) Etching in a hydrogenperoxyde-con~A;nln~
19 hydrochloric ~cidic copper chloride solution;
21 (17) Removing the etch-resistant mask as ~ell as ~2 the hole fillings with trichlorethylene and 23 a spray etcher.
Example 2 26 The base material is an epoxy resin paper provided on 27 both sides with an adhesive layer. The board is f~r~t 28 provided with those holes whose walls are to be metallized.
~9 The adhesive layer is rendered wettable and microporous in a known manner. Subsequently, the surface including ~he hole ;
,, O ~P
1 walls are catalysed for the deposition of co?per from electro-2 less copper deposition baths; then, a thin copper layer is 3 deposited from a commercially available electroless deposl-4 tion bath. The further process steps are as described in Example 1, steps (11) through (17).
7 Exa~Dle 3 8 The process of Examples 1 or 2 is usedi in step (13), however, 9 a W -curable screen printing ink is employed and the printed mask is cured by W radiation.
12 Example 4 14 The process of Example 3 is used, with the copper layer being produced solely by electroless copper deposition.
2~
- ~ g
21 (17) Removing the etch-resistant mask as ~ell as ~2 the hole fillings with trichlorethylene and 23 a spray etcher.
Example 2 26 The base material is an epoxy resin paper provided on 27 both sides with an adhesive layer. The board is f~r~t 28 provided with those holes whose walls are to be metallized.
~9 The adhesive layer is rendered wettable and microporous in a known manner. Subsequently, the surface including ~he hole ;
,, O ~P
1 walls are catalysed for the deposition of co?per from electro-2 less copper deposition baths; then, a thin copper layer is 3 deposited from a commercially available electroless deposl-4 tion bath. The further process steps are as described in Example 1, steps (11) through (17).
7 Exa~Dle 3 8 The process of Examples 1 or 2 is usedi in step (13), however, 9 a W -curable screen printing ink is employed and the printed mask is cured by W radiation.
12 Example 4 14 The process of Example 3 is used, with the copper layer being produced solely by electroless copper deposition.
2~
- ~ g
Claims (15)
1. A process for the manufacture of printed circuit boards with metallized hole walls on any suitable insulating base material provided on one or both sides with a metal layer comprising the steps of providing said base material with those holes whose walls are metal-coated in the finished circuit board, and depositing a metal layer of desired thickness on the walls of said holes and the surface or selected areas of the surface of said base material in known manner, c h a r a c t e r i z e d in that a masking layer is applied to said metal-coated surface(s) of said base material by screen printing a positive image of the desired circuit pattern;
and that said holes provided with metallized walls are sub-sequently filled with a resinous ink composition employing a screen printing stencil provided on the side facing the surface of said base material during use with a foil securely fixed to the screen of said stencil; and that said screen and said foil are provided with holes at locations corres-ponding to the holes with metallized walls in the circuit pattern; and that said resinous ink composition is pressed into the holes of said base material by means of a squeegee;
and that the unmasked areas of the metal layer on the surface of said base material are etched away in known manner; and, finally, that the masking layer applied by screen printing and the said ink composition in said holes are removed by the agency of one or more suitable solvents.
and that said holes provided with metallized walls are sub-sequently filled with a resinous ink composition employing a screen printing stencil provided on the side facing the surface of said base material during use with a foil securely fixed to the screen of said stencil; and that said screen and said foil are provided with holes at locations corres-ponding to the holes with metallized walls in the circuit pattern; and that said resinous ink composition is pressed into the holes of said base material by means of a squeegee;
and that the unmasked areas of the metal layer on the surface of said base material are etched away in known manner; and, finally, that the masking layer applied by screen printing and the said ink composition in said holes are removed by the agency of one or more suitable solvents.
2. The process of claim 1, characterized in that the holes in the screen stencil and the foil attached to it have a larger diameter than the holes in the base material, thus securing that, when applying the resinous ink composition to fill the holes, all areas not covered with the etching mask remain free of said resinous ink composition.
3. The process of claim 1 characterized in that the holes in the screen and the foil are produced by drilling.
4. The process of claims 1 to 3, characterized in that the resinous ink composition used for filling the holes, when drying, forms an etch-resistant film on the surface while the ink composition in the holes underneath the surface film remains in a state of high viscosity.
5. The process of claim 1, characterized in that the screen printable ink composition(s) used for producing the etch-resistant masking layer is (are) hardened by UV-radiation.
6. The process of claims 1 to 3, characterized in that the metal layer covering the surface of the base material as well as the hole walls is copper.
7. The process of claim 1, characterized in that the foil of the screen printing stencil is fixed to the screen by means of an adhesive.
8. The process of claims 1, characterized in that said foil has a thickness of 0.1 mm or less.
9. The process of claims 1, 7 and 8, characterized in that the foil is an aluminum foil.
10. The process of claims 1, 7 and 8, characterized in that the foil is plastic foil.
11. The process of claim 2, characterized in that the holes in the screen and the foil are produced by drilling.
12. The process of claim 7, characterized in that said foil has a thickness of 0.1 mm or less.
13. A screen printing stencil for use in the process of the manufacture of printed circuit boards with metallized hole wall on any suitable insulating base material provided on one or both sides with a metal layer and comprising the steps of providing said base material with those holes whose walls are metal-coated in the finished circuit board, and depositing a metal layer of desired thickness on the walls of said holes and the surface of selected areas of the surface of said base material in known manner and characterized in that a masking layer is applied to said metal-coated surface(s) of said base material by screen printing a positive image of the desired circuit pattern; and that said holes provided with metallized walls are subsequently filled with resinous ink composition employing a screen printing stencil provided on the side facing the surface of the base material during use with a foil securely fixed to the screen of the stencil; and that said screen and foil are provided with holes at locations corresponding to the holes with metallized walls in the circuit pattern, and that said resinous ink composition is pressed into the holes of said base material by means of a squeegee; and that the unmasked areas of the metal layer on the surface of said base material are etched away in known manner, and finally, that the masking layer applied by screen printing and the said ink composition in said holes are removed by an agency of one or more suitable solvents, said screen printing stencil being characterized in that the screen is fastened to a frame and is provided with a foil, said foil being securely fixed to the surface of said screen which is not in contact with the squeegee during the hole filling process; and, that said screen and foil are provided with holes at locations corresponding to the hole pattern in the base material.
14. The screen printing stencil of claim 13, characterized in that the foil is a plastic or a metal foil of a maximal thickness of 0.1 mm.
15. The screen printing stencil of claim 13, characterized in that the foil is fixed to the screen by means of an adhesive.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3217983.9-34 | 1982-05-13 | ||
| DE3217983A DE3217983C2 (en) | 1982-05-13 | 1982-05-13 | Method for making a masking mask |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1196731A true CA1196731A (en) | 1985-11-12 |
Family
ID=6163461
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000428115A Expired CA1196731A (en) | 1982-05-13 | 1983-05-13 | Process and device for the manufacture of printed circuit boards |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS58206192A (en) |
| CA (1) | CA1196731A (en) |
| CH (1) | CH659753A5 (en) |
| DE (1) | DE3217983C2 (en) |
| DK (1) | DK210983A (en) |
| GB (1) | GB2120017B (en) |
| IT (1) | IT1197651B (en) |
| NL (1) | NL8301586A (en) |
| SE (1) | SE8302619L (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3514093A1 (en) * | 1985-04-16 | 1986-10-23 | Kaspar 5241 Gebhardshain Eidenberg | METHOD FOR CLOSING HOLES PROVIDED IN A CIRCUIT BOARD |
| US4884337A (en) * | 1986-11-26 | 1989-12-05 | Epicor Technology, Inc. | Method for temporarily sealing holes in printed circuit boards utilizing a thermodeformable material |
| US4748742A (en) * | 1986-11-26 | 1988-06-07 | Multitek Corporation | Method for temporarily sealing holes in printed circuit boards |
| US6276055B1 (en) | 1998-09-02 | 2001-08-21 | Hadco Santa Clara, Inc. | Method and apparatus for forming plugs in vias of a circuit board layer |
| US6506332B2 (en) | 2000-05-31 | 2003-01-14 | Honeywell International Inc. | Filling method |
| US6800232B2 (en) | 2000-05-31 | 2004-10-05 | Ttm Advanced Circuits, Inc. | PCB support plate method for PCB via fill |
| KR20030007753A (en) | 2000-05-31 | 2003-01-23 | 허니웰 인터내셔날 인코포레이티드 | Filling method |
| DE10196259T1 (en) | 2000-05-31 | 2003-05-15 | Honeywell Int Inc | filling |
| US6454154B1 (en) | 2000-05-31 | 2002-09-24 | Honeywell Advanced Circuits, Inc. | Filling device |
| US6855385B2 (en) | 2000-05-31 | 2005-02-15 | Ttm Advanced Circuits, Inc. | PCB support plate for PCB via fill |
| CN110557889A (en) * | 2018-05-30 | 2019-12-10 | 胜宏科技（惠州）股份有限公司 | Manufacturing method of aluminum sheet screen hole plugging |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1249966B (en) * | 1967-09-14 | Ruwel-Werke, Spezialfabrik für Hochfrequenzbauteile, Inh. Ing. Fritz Stahl, Geldern (RhId.) | Process for the production of metallized walls of bores in printed circuit boards | |
| GB1042234A (en) * | 1965-03-05 | 1966-09-14 | Mullard Ltd | Multilayer printed circuits |
| GB1194853A (en) * | 1967-02-16 | 1970-06-17 | Btr Industries Ltd | A Method of Forming Printed Circuits |
| JPS52118261A (en) * | 1976-03-30 | 1977-10-04 | Matsushita Electric Ind Co Ltd | Method of producing through hole printed circuit board |
| JPS5658797A (en) * | 1979-10-18 | 1981-05-21 | Yashima Denki Kk | Ac power control circuit in induction motor |
| JPS5667985A (en) * | 1979-11-08 | 1981-06-08 | Matsushita Electric Ind Co Ltd | Method of printing ink using metal mask |
-
1982
- 1982-05-13 DE DE3217983A patent/DE3217983C2/en not_active Expired
-
1983
- 1983-05-03 GB GB08312009A patent/GB2120017B/en not_active Expired
- 1983-05-04 NL NL8301586A patent/NL8301586A/en not_active Application Discontinuation
- 1983-05-06 SE SE8302619A patent/SE8302619L/en not_active Application Discontinuation
- 1983-05-10 JP JP58083445A patent/JPS58206192A/en active Pending
- 1983-05-10 CH CH2557/83A patent/CH659753A5/en not_active IP Right Cessation
- 1983-05-11 DK DK210983A patent/DK210983A/en not_active Application Discontinuation
- 1983-05-13 CA CA000428115A patent/CA1196731A/en not_active Expired
- 1983-05-13 IT IT48288/83A patent/IT1197651B/en active
Also Published As
| Publication number | Publication date |
|---|---|
| DE3217983A1 (en) | 1983-11-17 |
| SE8302619D0 (en) | 1983-05-06 |
| SE8302619L (en) | 1983-11-14 |
| GB2120017B (en) | 1986-02-19 |
| IT1197651B (en) | 1988-12-06 |
| DK210983A (en) | 1983-11-14 |
| GB8312009D0 (en) | 1983-06-08 |
| DE3217983C2 (en) | 1984-03-29 |
| IT8348288A0 (en) | 1983-05-13 |
| NL8301586A (en) | 1983-12-01 |
| GB2120017A (en) | 1983-11-23 |
| CH659753A5 (en) | 1987-02-13 |
| DK210983D0 (en) | 1983-05-11 |
| JPS58206192A (en) | 1983-12-01 |
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| MKEC | Expiry (correction) | ||
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