EP4077768A1 - Electroforming process - Google Patents
Electroforming processInfo
- Publication number
- EP4077768A1 EP4077768A1 EP20829037.9A EP20829037A EP4077768A1 EP 4077768 A1 EP4077768 A1 EP 4077768A1 EP 20829037 A EP20829037 A EP 20829037A EP 4077768 A1 EP4077768 A1 EP 4077768A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- layer
- substrate
- photoresist
- layers
- intermediate structure
- 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.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 25
- 238000005323 electroforming Methods 0.000 title claims abstract description 14
- 239000000758 substrate Substances 0.000 claims abstract description 50
- 229910052751 metal Inorganic materials 0.000 claims abstract description 13
- 239000002184 metal Substances 0.000 claims abstract description 13
- 229920002120 photoresistant polymer Polymers 0.000 claims description 36
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 34
- 239000000463 material Substances 0.000 claims description 25
- 238000000576 coating method Methods 0.000 claims description 22
- 239000011248 coating agent Substances 0.000 claims description 21
- 229910052703 rhodium Inorganic materials 0.000 claims description 20
- 239000010948 rhodium Substances 0.000 claims description 20
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical group [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims description 19
- 229910052759 nickel Inorganic materials 0.000 claims description 17
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 11
- 229910052802 copper Inorganic materials 0.000 claims description 11
- 239000010949 copper Substances 0.000 claims description 11
- 229910000990 Ni alloy Inorganic materials 0.000 claims description 4
- 238000005530 etching Methods 0.000 claims description 4
- 229910000531 Co alloy Inorganic materials 0.000 claims 1
- 229910000629 Rh alloy Inorganic materials 0.000 claims 1
- QXZUUHYBWMWJHK-UHFFFAOYSA-N [Co].[Ni] Chemical compound [Co].[Ni] QXZUUHYBWMWJHK-UHFFFAOYSA-N 0.000 claims 1
- 238000004070 electrodeposition Methods 0.000 description 5
- -1 rhodium cations Chemical class 0.000 description 3
- 238000009713 electroplating Methods 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 239000004332 silver Substances 0.000 description 2
- 238000004528 spin coating Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
- 229910001252 Pd alloy Inorganic materials 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000005137 deposition process Methods 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- BSIDXUHWUKTRQL-UHFFFAOYSA-N nickel palladium Chemical compound [Ni].[Pd] BSIDXUHWUKTRQL-UHFFFAOYSA-N 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- IIACRCGMVDHOTQ-UHFFFAOYSA-M sulfamate Chemical compound NS([O-])(=O)=O IIACRCGMVDHOTQ-UHFFFAOYSA-M 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D1/00—Electroforming
- C25D1/003—3D structures, e.g. superposed patterned layers
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D1/00—Electroforming
- C25D1/04—Wires; Strips; Foils
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D1/00—Electroforming
- C25D1/10—Moulds; Masks; Masterforms
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/12—Electroplating: Baths therefor from solutions of nickel or cobalt
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D3/00—Electroplating: Baths therefor
- C25D3/02—Electroplating: Baths therefor from solutions
- C25D3/50—Electroplating: Baths therefor from solutions of platinum group metals
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/02—Electroplating of selected surface areas
- C25D5/022—Electroplating of selected surface areas using masking means
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/10—Electroplating with more than one layer of the same or of different metals
- C25D5/12—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium
Definitions
- the present invention relates to an electroforming process for forming a metal structure.
- Electroforming is an electrodeposition process for forming a product of one or more metal layers on a removable substrate.
- the substrate is placed in an electrolytic bath in electrical contact with a cathode.
- ions of the metal to be deposited are solved into the electrolyte. These ions flow to the substrate where they are replenished with electrons and deposit on the substrate surface as a layer of neutral metal molecules.
- the metal product Once the metal product has a desired thickness, it is removed from the substrate.
- a pattern of a non-conductive coating is applied on parts of the substrate defining the geometrical outline of the structure to be electroformed.
- a non- conductive coating is usually applied on the substrate by means of a photolithographic process using a UV-sensitive photoresist coating material.
- the photoresist can for example be applied by spin coating to obtain a very smooth layer of uniform thickness.
- Parts of the photoresist are selectively exposed to UV-light, e.g., by using laser direct imaging (LDI), or by using a photomask. If the photoresist is a positive photoresist, the exposed parts are removed. If the photoresist is a negative photoresist, the non-exposed parts are removed.
- a patterned coating of the photoresist will remain on the substrate.
- the electrically conductive substrate with the photoresist pattern forms a mandrel. Electroforming will only take place on sections of the substrate not shielded by the photoresist pattern.
- US 2005/0253606 discloses an electrodeposition process for forming complex multi-layer structures with staggered layers and recesses. Each layer must be planarized before a next layer can be applied.
- NL 1031259 discloses an electroforming process involving forming a metal layer on a substrate and a sacrificial layer supporting the structure after removal of the substrate.
- the object of the invention is achieved with a process of electroforming a metal structure, the process comprising the following steps:
- a first layer is deposited on a substrate followed by one or more next layers partially overlapping the first layer to form an intermediate structure having a substrate surface facing the substrate;
- the intermediate structure is removed from the substrate and one or more further layers are deposited on said substrate surface of the intermediate structure .
- the uncovered surface of the intermediate structure is just as flat as the substrate it was made on. Therefore, further layers can be applied on this side of the intermediate structure without the need of first planarizing it.
- the first layer itself can comprise one or more layers.
- the partially overlapping layer can comprise one or more layers.
- the layers can be formed by electrodeposition.
- the first layer protrudes relative to this next layer.
- the first layer will also protrude relative to the one or more layers on the substrate surface of the intermediate structure. This way, the first layer will protrude from the outer layers at both sides, e.g., to form a tip.
- the layers at both sides of the first layer may be symmetrical or asymmetrical.
- a layer of a sacrificial material is formed over the intermediate structure before the intermediate structure is removed from the substrate.
- the layer of sacrificial material can removed, for example by selective etching. Suitable sacrificial materials include for example copper, silver or a polymeric material.
- the body of sacrificial material forms an auxiliary substrate, supporting the intermediate structure after removal of the substrate when the further layers are applied on the substrate side of the intermediate structure.
- the substrate side is the side of the intermediate structure directly contacted by the substrate before removal of the substrate.
- the substrate is a mandrel with a non-conductive coating pattern, such as a photoresist pattern, defining an outline of at least the first layer.
- the first layer can be deposited very accurately without overgrowing the respective photoresist.
- the photoresist Before forming the overlapping layer, the photoresist can be at least partially removed so a new photoresist pattern can be applied to confine the overlapping layer.
- the complete photoresist coating can completely be removed and replaced with a fresh photoresist coating of the desired patter.
- the first layer can be of a different material than the overlapping layer and/or the layers deposited on the opposite side.
- This is particularly suitable for making a structure with a multilayer body of a first material, such as nickel or a nickel alloy, and a protruding tip of a second material, such as rhodium.
- a structure can for example be used as a test probe of a probe card for testing semiconductors on a wafer.
- the process may for example comprise the following steps to manufacture a structure with a tip:
- the first layer is covered with a fresh non-conductive coating, e.g., a photoresist;
- parts of the non-conductive coating are removed to expose a part of the substrate, adjacent one side of the first layer;
- the remaining parts of the non-conductive coating are removed and the body of sacrificial material is applied on top of the first and third layers;
- the substrate is removed to expose a substrate side of the intermediate structure
- a further non-conductive coating is applied covering the part of the first layer projecting from the third layer and covering uncovered parts of the sacrificial layer adjacent the first layer;
- the non-conductive coating and the sacrificial material are removed.
- Substrates for electroforming are made of conductive material, e.g., a metal, passivated to allow subsequent separation of the finished electroformed structure.
- Non- conductive substrates can for example be made of glass, silicon, or plastic polymeric material, and require the deposition of a conductive layer prior to electrodeposition.
- the sacrificial material can be any material allowing selective etching without affecting the materials of the final structure. Suitable sacrificial materials include for instance copper, silver or polymeric materials.
- the non-conductive coating is typically a photoresist material, e.g., a positive or negative photoresist, although other types of non-conductive coatings can also be used, if so desired.
- the process according to the present invention allows producing multilayer metal structures with projecting inner layers on any scale, also on a very small scale, e.g., micrometer-scale, in a very accurate and reliable manner.
- the thickness of the photoresist layer can for example be in the range of 10 to 100 micrometer, but can also be outside this range, if so desired.
- the thickness of the electroformed layers can for example be in the range of 10 to 100 micrometer per layer, but can also be outside this range, if so desired.
- suitable metals include, inter alia, nickel, nickel alloys, such as nickel-palladium alloy; chromium, rhodium, copper or copper alloys.
- suitable electroplating baths for nickel include, i.a., a Watts bath (NiS04), a sulphamate bath, and examples of suitable electroplating baths for copper include a copper sulphate bath.
- Figure 1A shows a substrate 2 partly covered by a non- conductive coating of a photoresist 3.
- the photoresist 3 is applied, e.g., by means of spin coating, to form a UV- sensitive coating of a uniform thickness.
- Parts of the photoresist 3 are removed after selective exposure to UV- light, e.g., by means of laser direct imaging.
- the top surface 2 of the substrate 1 has conductive bare sections 4 and non-conductive sections 3 coated with the photoresist, as shown in Figure 1A.
- the mandrel 1 is then placed in an electrolytic bath and electro-conductively connected to a cathode.
- a rhodium layer 7 is deposited on the conductive sections 4 of the mandrel 1 ( Figure IB).
- the thickness of the rhodium layer 7 does not exceed the thickness of the photoresist 3.
- the mandrel 1 is then taken from the electrolytic bath and spin coated with a second photoresist layer 8, which covers the first photoresist 3 and the rhodium layer 7.
- the first photoresist may be removed and complete replaced by the fresh second photoresist. Parts of the second photoresist 8 are selectively exposed to UV for curing and the uncured parts are washed away.
- the first and second photoresist layers directly adjacent the rhodium layer 7 are removed leaving part of the substrate 2 uncovered ( Figure ID).
- the mandrel 1 is then placed in a second electrolytic bath and connected to the cathode, the anode being configured to release nickel cations.
- a nickel layer 9 is deposited on the uncovered electro-conductive section of the mandrel's top surface 2.
- the nickel layer 9 has the same thickness as the rhodium layer 7 ( Figure IE).
- the mandrel 1 is removed from the electrolytic bath and to allow removal of a part of the photoresist 8 on top of the rhodium layer 7 adjacent the nickel layer 9 ( Figure IF).
- the mandrel 1 is then returned to the same electrolytic bath and a further nickel layer 10 is electroformed on top of the uncovered part of the rhodium layer 7 and the first nickel layer 9 ( Figure 1G).
- the resulting intermediate structure has a rhodium tip projecting from a nickel body.
- the rest of the photoresist is subsequently removed (Figure 1H).
- the copper can be applied by means of electroforming or by any other suitable deposition process.
- the thickness of the copper layer is about the same as the thickness of the mandrel 1, but can be more if so desired.
- the copper, nickel and rhodium layers 7, 10, 11 are jointly removed from the mandrel 1 ( Figure 1J).
- the mandrel side 12 of the rhodium layer i.e., the side facing the mandrel before its removal, is now uncovered.
- This side 12 is just as flat as the mandrel surface 2 and therefore a very suitable substrate for electroforming further layers, without the need of a planarization step.
- a new photoresist layer 13 is applied and cured on top of the projecting part of the rhodium layer 7 (Figure IK). The rest of the rhodium layer 7 remains uncovered, just as the nickel layer 10.
- the structure is then returned into the second electrolytic bath and again connected to the cathode.
- a further layer 14 of nickel is deposited on the uncovered parts of the rhodium layer 7 and the adjacent surface of the nickel part 10 ( Figure 1L).
- the last photoresist 13 and the copper 11 can now be removed, e.g., by selective etching.
- the remaining final structure 15 comprises a nickel body 16 with one end sandwiching a projecting rhodium tip.
- the layer in line with the rhodium tip can be a different material, e.g., copper, e.g., sandwiched by layers of nickel or nickel alloys.
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL2024542A NL2024542B1 (en) | 2019-12-20 | 2019-12-20 | Electroforming process |
PCT/NL2020/050804 WO2021125959A1 (en) | 2019-12-20 | 2020-12-18 | Electroforming process |
Publications (1)
Publication Number | Publication Date |
---|---|
EP4077768A1 true EP4077768A1 (en) | 2022-10-26 |
Family
ID=69156478
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP20829037.9A Pending EP4077768A1 (en) | 2019-12-20 | 2020-12-18 | Electroforming process |
Country Status (8)
Country | Link |
---|---|
US (1) | US20230035647A1 (en) |
EP (1) | EP4077768A1 (en) |
JP (1) | JP2023507177A (en) |
KR (1) | KR20220118447A (en) |
CN (1) | CN114929942A (en) |
NL (1) | NL2024542B1 (en) |
TW (1) | TW202132626A (en) |
WO (1) | WO2021125959A1 (en) |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7241689B2 (en) | 2003-02-04 | 2007-07-10 | Microfabrica Inc. | Microprobe tips and methods for making |
NL1031259C2 (en) | 2006-03-01 | 2007-09-04 | Stork Veco Bv | Electroforming process for making metal products, e.g. hair clipper blades, involves forming metal layer on top of pacified surface of metal layer and applying sacrificial electrically insulating region onto exposed surfaces of two layers |
-
2019
- 2019-12-20 NL NL2024542A patent/NL2024542B1/en active
-
2020
- 2020-12-11 TW TW109143741A patent/TW202132626A/en unknown
- 2020-12-18 CN CN202080087142.XA patent/CN114929942A/en active Pending
- 2020-12-18 WO PCT/NL2020/050804 patent/WO2021125959A1/en unknown
- 2020-12-18 KR KR1020227023083A patent/KR20220118447A/en unknown
- 2020-12-18 JP JP2022537159A patent/JP2023507177A/en active Pending
- 2020-12-18 EP EP20829037.9A patent/EP4077768A1/en active Pending
- 2020-12-18 US US17/757,606 patent/US20230035647A1/en active Pending
Also Published As
Publication number | Publication date |
---|---|
JP2023507177A (en) | 2023-02-21 |
US20230035647A1 (en) | 2023-02-02 |
NL2024542B1 (en) | 2021-09-02 |
WO2021125959A1 (en) | 2021-06-24 |
CN114929942A (en) | 2022-08-19 |
KR20220118447A (en) | 2022-08-25 |
TW202132626A (en) | 2021-09-01 |
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Legal Events
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Effective date: 20220720 |
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Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
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RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: KNOL, HARM GERRIT Inventor name: BERENSCHOT, JOHANNES HENDRIKUS MARIA Inventor name: ALBERTS, ROY GERARDUS JOHANNES JOSEPH Inventor name: HILDENBRAND, NICOLAS Inventor name: MUENNINGHOFF, JORIS ANTONIUS WILHELMUS Inventor name: KUSTERS, MARCO HERMAN LAURENS HUBERT |
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DAX | Request for extension of the european patent (deleted) | ||
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