METHOD FOR NO-SILANE ELECTROLESS METAL DEPOSITION USING HIGH ADHESIVE CATALYST AND PRODUCT THEREFROM
20170081766 ยท 2017-03-23
Inventors
Cpc classification
C23C18/2086
CHEMISTRY; METALLURGY
C23C18/1893
CHEMISTRY; METALLURGY
C23C18/1844
CHEMISTRY; METALLURGY
C23C18/1639
CHEMISTRY; METALLURGY
C23C18/1851
CHEMISTRY; METALLURGY
C23C18/32
CHEMISTRY; METALLURGY
C23C18/1662
CHEMISTRY; METALLURGY
C23C18/1803
CHEMISTRY; METALLURGY
C23C18/1653
CHEMISTRY; METALLURGY
C23C18/2006
CHEMISTRY; METALLURGY
International classification
Abstract
A method for electroless metal deposition includes steps as follows. a) a substrate is provided, and the substrate has a surface which is subjected to a hydroxide surface modification to form a hydrophilic chemical oxide layer; b) a catalyst layer is formed on the chemical oxide layer, the catalyst layer includes a plurality of colloidal nanoparticles, and each of the plurality of colloidal nanoparticles includes a palladium nanoparticle and a high molecular polymer which wraps the palladium nanoparticle; and c) an electroless metal deposition is conducted, and a metal is deposited on the catalyst layer to form an electroless metal layer. An electroless metal layer included substrate is also provided.
Claims
1. A method for electroless metal deposition, comprising: a) providing a substrate, and the substrate having a surface which is subjected to a hydroxide surface modification to form a hydrophilic chemical oxide layer; b) forming a catalyst layer on the chemical oxide layer, the catalyst layer including a plurality of colloidal nanoparticles, and each of the plurality of colloidal nanoparticles including a palladium nanoparticle and a high molecular polymer which wraps the palladium nanoparticle; and c) conducting an electroless metal deposition, and a metal being deposited on the catalyst layer to form an electroless metal layer.
2. The method for electroless metal deposition as claimed in claim 1, wherein in the step a, the hydroxide surface modification includes a sulfuric peroxide mixture method, an ozonation method, a hydrogen plasma method, or a nitric acid method.
3. The method for electroless metal deposition as claimed in claim 1, wherein the step b further comprising using a protective agent and a precursor to form the catalyst layer on the chemical oxide layer, and the protective agent and the precursor have a weight ratio of 1:1.
4. The method for electroless metal deposition as claimed in claim 3, wherein the protective agent is the high molecular polymer, and the precursor is a palladium ion.
5. The method for electroless metal deposition as claimed in claim 1, wherein each of the plurality of colloidal nanoparticles has a particle size ranging from 6 nm to 10 nm.
6. The method for electroless metal deposition as claimed in claim 1, wherein the high molecular polymer wrapping the palladium nanoparticle is a polyvinyl alcohol polymer, a polyvinyl alcohol acid polymer, a poly(vinyl alcohol-co-ethylene) polymer, or a poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) polymer.
7. The method for electroless metal deposition as claimed in claim 1, wherein the high molecular polymer is a low-degree-polymerization polyvinyl alcohol polymer with its molecular weight ranging from 20000 to 30000.
8. The method for electroless metal deposition as claimed in claim 1, wherein in the step c, during the electroless metal deposition, the metal being deposited on the catalyst layer is nickel or copper.
9. The method for electroless metal deposition as claimed in claim 1, wherein the colloidal nanoparticles is formed by reacting a precursor, a protective agent, and a reducing agent in an alkaline environment.
10. The method for electroless metal deposition as claimed in claim 9, wherein the precursor is a palladium ion, the protective agent is the high molecular polymer, and the reducing agent is a formaldehyde solution.
11. The method for electroless metal deposition as claimed in claim 9, wherein the precursor is at least one palladium nanoparticle, the protective agent is at least one high molecular polymer, and the at least one high molecular polymer wraps the at least one palladium nanoparticle to form at least one colloidal nanoparticle.
12. The method for electroless metal deposition as claimed in claim 11, wherein the at least one high molecular polymer wrapping the at least one palladium nanoparticle is a polyvinyl alcohol polymer, a polyvinyl alcohol acid polymer, a poly(vinyl alcohol-co-ethylene) polymer, or a poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) polymer.
13. A method for metal deposition, comprising: a) providing a substrate, and the substrate having a surface which is subjected to a hydroxide surface modification to form a hydrophilic chemical oxide layer; b) forming a catalyst layer on the chemical oxide layer, the catalyst layer including a plurality of colloidal nanoparticles, and each of the plurality of colloidal nanoparticles including a palladium nanoparticle and a high molecular polymer which wraps the palladium nanoparticle; and c) conducting an electroless metal deposition to form a metal layer on the catalyst layer.
14. The method of claim 13, further comprising d) conducting an electro-plating to increase the thickness of the metal layer.
15. The method of claim 13, wherein the step b further comprising using the high molecular polymer and a palladium ion to form the catalyst layer on the chemical oxide layer.
16. An electroless metal layer included substrate, comprising: a chemical oxide layer formed by conducting a hydroxide surface modification on a surface of a substrate; a catalyst layer located on the chemical oxide layer, and the catalyst layer including a plurality of colloidal nanoparticles, and each of the plurality of colloidal nanoparticles including a palladium nanoparticle and a high molecular polymer which wraps the palladium nanoparticle; and an electroless metal layer formed by conducting an electroless metal deposition to deposit a metal on the catalyst layer.
17. The electroless metal layer included substrate as claimed in claim 16, wherein each of the plurality of colloidal nanoparticles has a particle size ranging from 6 nm to 10 nm.
18. The electroless metal layer included substrate as claimed in claim 16, wherein the high molecular polymer wrapping the palladium nanoparticle includes a polyvinyl alcohol polymer, a polyvinyl alcohol acid polymer, a poly(vinyl alcohol-co-ethylene) polymer, or a poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) polymer.
19. The electroless metal layer included substrate as claimed in claim 16, wherein the high molecular polymer is a low-degree-polymerization polyvinyl alcohol polymer with its molecular weight ranging from 20000 to 30000.
20. The electroless metal layer included substrate as claimed in claim 16, wherein the metal includes nickel or copper.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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[0017]
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[0023]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Embodiments disclosed in the instant disclosure are illustrated via specific examples as follows, and people familiar in the art may easily understand the advantages and efficacies of the instant disclosure by disclosure of the specification. The instant disclosure may be implemented or applied by other different specific examples, and each of the details in the specification may be applied based on different views and may be modified and changed under the existence of the spirit of the instant disclosure. The figures in the instant disclosure are only for brief description, but they are not depicted according to actual size and do not reflect the actual size of the relevant structure. The following embodiments further illustrate related technologies of the instant disclosure in detail, but the scope of the instant disclosure is not limited herein.
First Embodiment
[0025] Please refer to
[0026] Please refer to
[0027] Firstly, a substrate 1 (a silicon substrate is illustrated in the instant disclosure) is provided, and the substrate 1 is cleaned using an RCA cleaning method. The RCA cleaning method is a standard procedure for wet cleaning in the industry. RCA-1 and RCA-2 are two reagents used in the RCA cleaning method. The ingredients of RCA-1 are NH.sub.4OH, H.sub.2O.sub.2, and H.sub.2O (also known as APM), and the RCA-1 is used to remove organic particles on a surface. The ingredients of RCA-2 are HCl, H.sub.2O.sub.2, and H.sub.2O (also known as HPM), and the RCA-2 is used to remove metals on a surface. In the instant disclosure, an APM solution of the RCA cleaning method is used in the cleaning procedure to clean the organic particles on the surface. The cleaning procedure includes the following steps. The substrate 1 is soaked in the APM solution for 20 minutes at 80 C., and the APM solution has a ratio of NH.sub.4OH : H.sub.2O.sub.2 : DI=1:1:5 (DI is deionized water). The substrate 1 is then soaked into a 2% hydrofluoric acid (HF) aqueous solution to remove an oxide layer on the surface. Then, a sulfuric peroxide mixture (SPM) or an ozone is used to conduct a hydroxide surface modification on a surface of the substrate 1, and the substrate 1 is soaked into the SPM (H.sub.2SO.sub.4H.sub.2O.sub.2) with a volume ratio of 3:1 for 10 minutes, so as to hydroxylate the surface of the substrate 1 and to form a hydroxylated chemical oxide layer 2 on the surface (as shown in the leftmost figure of
[0028] Next, the surface modified substrate 1 is soaked in a PVA-Pd (polyvinyl alcohol polymer-palladium) solution for 5 minutes at 40 C., and the PVA-Pd is attached to the chemical oxide layer 2 of the surface of the substrate 1, so as to form a catalyst layer 3 (as shown in the middle figure of
[0029] Please refer to
[0030] Then, as shown in
[0031] Please refer to
[0032] Each of the colloidal nanoparticles 31 of this embodiment is such that, at least one protective agent wraps at least one precursor. Specifically, the protective agent is at least one polyvinyl alcohol polymer 312 and the precursor is at least one palladium nanoparticle 311, and the at least one polyvinyl alcohol polymer 312 wraps the at least one palladium nanoparticle 311 to form at least one colloidal nanoparticle 31.
[0033] Each of the colloidal nanoparticles 31 of this embodiment has a particle size ranging from 6 nm to 10 nm, and the protective agent and the precursor in each of the colloidal nanoparticles 31 have a weight ratio of 1:1. The at least one polyvinyl alcohol polymer 312 could be a low-degree-polymerization polyvinyl alcohol polymer with its molecular weight ranging from 20000 to 30000, and the alcoholysis degree of polyvinyl alcohol polymer 312 could be 88%.
Second Embodiment
[0034] Please refer to
[0035] 1) Rinsing: firstly, the substrate 1 is placed into the 2% hydrofluoric acid (HF) aqueous solution for 2 minutes to remove an oxide layer which is generated in the RCA cleaning process and/or generated naturally. The substrate 1 is soaked into the SPM with a volume ratio of H.sub.2SO.sub.4: H.sub.2O.sub.2 being 3:1 for 10 minutes at about 70 C. to 80 C., so as to conduct the hydroxide surface modification on the surface of the substrate 1 to form a hydroxylated chemical oxide layer 2 on the surface of the substrate 1. In the second embodiment, the SPM also can be replaced with ozone (O.sub.3), nitrate (HNO.sub.3), a mixture of nitrate (HNO.sub.3) and hydrofluoric acid (HF; 500 ppm), or hydrofluoric acid (HF; 100 ppm).
[0036] 2) Soaking: after the chemical oxide layer 2 formed substrate 1 is taken out from the SPM, the surface of the substrate 1 of the chemical oxide layer 2 is rinsed with deionized water, and the chemical oxide layer 2 formed substrate 1 is soaked in the PVA-Pd solution for 5 minutes at 40 C., such that a center of the palladium of the PVA-Pd may interact with hydroxyl groups and the PVA-Pd may absorb on the surface of the substrate 1 of the chemical oxide layer 2, so as to form a catalyst layer 3.
[0037] 3) Electroless-nickel deposition: the chemical oxide layer 2 and catalyst layer 3 formed substrate 1 is placed into the electroless nickel plating solution having a pH of 4.9 (or about pH of 4.5 to 5.0) at 80 C. (or about 75 C. to 85 C.) to conduct the electroless metal deposition for 1 minute. During the process of electroless metal deposition, the catalyst PVA-Pd on the surface of the chemical oxide layer 2 and catalyst layer 3 formed substrate 1 may effectively decrease an active energy which is required for a reaction, so as to facilitate hypophosphite ions and nickel ions to generate redox reactions on the surface of the chemical oxide layer 2 and catalyst layer 3 formed substrate 1, and an electroless nickel phosphorus layer (electroless metal layer 4) with approximately 200 nm thickness may be deposited.
[0038] The 200 nm thickness of electroless metal layer 4 on the substrate 1 may not be enough for some applications. Therefore, after the electroless metal layer 4 being formed on the substrate 1 according to the instant disclosure, additional process like conventional electro-plating process may also be performed to the substrate 1 so as to deposit more metal onto the metal layer and increase the thickness of the metal layer to meet the needs of some applications.
[0039] The preparation method of the PVA-Pd solution in this embodiment may be identical to that in the first embodiment, thus it is not repeated herein.
[0040] The method for forming the colloidal nanoparticle 31 in this embodiment may be identical to that in the first embodiment. In addition, the PVA is used as an example in the first embodiment. In this embodiment, the high molecular polymer used to wrap the palladium nanoparticle may include but not limited to a polyvinyl alcohol polymer, a polyvinyl alcohol acid polymer, a poly(vinyl alcohol-co-ethylene) polymer, or a poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) polymer.
Third Embodiment
[0041] In the third embodiment, the steps of the method for no-silane electroless metal deposition using the high adhesive catalyst are identical to that of the second embodiment, and also include main three steps: conducting a hydroxide surface modification on a surface of a substrate 1 to form a chemical oxide layer 2, forming a catalyst layer 3 on the chemical oxide layer 2, and conducting an electroless metal deposition to form an electroless metal layer 4. A silicon substrate is also illustrated as the substrate 1. The cleaning method of the substrate 1, the composition of the catalyst layer 3, the electroless metal deposition steps, the method for forming the colloidal nanoparticles 31 being used to the no-silane electroless metal deposition, and the composition of the colloidal nanoparticles 31 may all be identical to those of the second embodiment, thus they are not repeated herein. The difference between the third embodiment and the second embodiment is that, in the third embodiment, a RCA method is used for conducting the hydroxide surface modification on the surface of the substrate 1.
[0042]
[0043] 1) Rinsing: the substrate 1 is placed into a 2% hydrofluoric acid (HF) aqueous solution for 2 minutes to remove an oxide layer which is generated in the RCA cleaning process and/or generated naturally. The substrate 1 is soaked into a solvent with a volume ratio of NH.sub.4OH: H.sub.2O.sub.2: DI-water being 1:1:5 for 20 minutes at 80 C., so as to conduct the hydroxide surface modification on the surface of the substrate 1 to form a hydroxylated chemical oxide layer 2 on the surface of the substrate 1.
[0044] 2) Soaking: the substrate 1 is soaked into the PVA-Pd solution for 5 minutes at 40 C., such that a center of the palladium of the PVA-Pd can interact with the hydroxyl groups and the PVA-Pd absorb onto the surface of the substrate 1 of the chemical oxide layer 2, so as to form a catalyst layer 3. The preparation method of the PVA-Pd solution in this embodiment can be identical to that in the first and second embodiments, thus it is not repeated herein.
[0045] 3) Electroless-nickel deposition: the chemical oxide layer 2 and catalyst layer 3 formed substrate 1 is placed into the electroless nickel plating solution having a pH of 4.9 (or about pH of 4.5 to 5.0) at 80 C. (or about 75 C. to 85 C.) to conduct the electroless metal deposition for 1 minute. During the process of electroless metal deposition, the catalyst PVA-Pd on the surface of the chemical oxide layer 2 and catalyst layer 3 formed substrate 1 can effectively decrease an active energy which is required for a reaction, so as to facilitate hypophosphite ions and nickel ions to generate redox reactions on the surface of the chemical oxide layer 2 and catalyst layer 3 formed substrate 1, and an electroless nickel phosphorus layer (electroless metal layer 4) with approximately 200 nm thickness is deposited.
[0046] The 200 nm thickness of electroless metal layer 4 on the substrate 1 may not be enough for some applications. Therefore, after the electroless metal layer 4 being formed on the substrate 1 according to the instant disclosure, additional process like conventional electro-plating process may also be performed to the substrate 1 so as to deposit more metal onto the metal layer and increase the thickness of the metal layer to meet the needs of some applications.
[0047] In the third embodiment, the RCA method is used to conduct the hydroxide surface modification on the surface of the substrate 1, but in other embodiments, it also can be replaced with a sulfuric peroxide mixture method, an ozonation method, a hydrogen plasma method, or a nitric acid method. In addition, while the PVA is used as an example in the third embodiment, however, the high molecular polymer used to wrap the palladium nanoparticle may also include but not limited to a polyvinyl alcohol polymer, a polyvinyl alcohol acid polymer, a poly(vinyl alcohol-co-ethylene) polymer, or a poly(vinyl butyral-co-vinyl alcohol-co-vinyl acetate) polymer.
[0048] Via the method for no-silane electroless metal deposition using the high adhesive catalyst can achieve the following experimental results.
[0049] <Experimental Result 1: XPS Spectrum Analysis>
[0050] Please refer to
[0051] As shown in
[0052] <Experimental Result 2: Water Droplet Contact Angle (Hydrophilicity) Experiment>
[0053] In order to understand a degree of change of the hydrophilicity of the surface of the substrate 1 after which is conducted the SPM method in the second embodiment and the RCA method in the third embodiment in this instant disclosure, the water droplet contact angle experiment is used for measurement. Please refer to
[0054] <Experimental Result 3: Electroless Nickel Layer Adhesion Experiment>
[0055] Please refer to
[0056] The descriptions illustrated supra set forth simply the preferred embodiments of the instant disclosure; however, the characteristics of the instant disclosure are by no means restricted thereto. All changes, alterations, or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the instant disclosure delineated by the following claims.