Method and use for cleaning non-conductive surfaces

Abstract

The present invention is a method for cleaning a non-conductive surface of a non-conductive layer, wherein the non-conductive layer is based on a composite of an organic polymer and a glass filler, includes blind microvias (BMVs) for the fabrication of articles having integrated circuits, the non-conductive surface includes non-conductive walls of the BMVs, the non-conductive layer is bonded to a copper layer, the copper layer forms the bottom of the BMVs, and in the following order: (i) preparing the non-conductive surface of the non-conductive layer; (ii) treating the surface prepared in step (i) using a desmear process including, in this order, the steps of (t1) treating the surface prepared using a swelling agent solution containing water and an organic solvent, (t2) treating the surface using an aqueous etching solution containing an oxidizing agent, and (t3) treating the surface using an aqueous reducing solution containing a reducing agent; (iii) treating the surface treated in step (ii) using an aqueous alkaline cleaning agent solution to remove the glass filler; and (iv) drying the surface treated in step (iii) to obtain a dry surface, preferably a water-free surface, and relates to the use of the method.

Description

Technical Field

[0001] The present invention relates to a novel method for cleaning the non-conductive surface of a non-conductive layer based on a composite of an organic polymer and a glass filler and containing blind microvias (BMVs) for the fabrication of articles having integrated circuits, and to its use. In particular, the method is used for removing the glass filler from the non-conductive surface including the walls of the blind microvias and, in particular, for preparing a cleaned surface for subsequent pretreatment and metallization, for the fabrication of articles such as multilayer assemblies as printed circuit boards, in particular fine line IC substrate boards where circuit features as blind microvias can be filled with metal. In particular, the method is useful for SAP applications.

Background Art

[0002] Modern electronic device manufacturers are faced with the increasing demand for miniaturization and need to pursue the trend of more densely interconnected multilayer printed circuit boards. Epoxy-based composites are the insulation materials of choice as a first option because of their low cost and well-balanced physicochemical and mechanical properties. The latest epoxy build-up laminates have an increasing amount of spherical glass filler required to compensate for the CTE mismatch between the epoxy-based resin matrix and the electroplated copper circuit. Furthermore, their small size on the order of microns allows for a smoother surface topography compared to glass fiber bundle reinforced base materials.

[0003] After inserting various recesses, such as traces, blind microvias (BMVs), or through-holes (THs), into a resin-based substrate containing glass fillers by mechanical or laser drilling, a series of different wet chemical processes are applied to the substrate surface. Such processes include a wet chemical desmear process to remove residue from the drilling process, followed by a pretreatment process to prepare the surface for subsequent electroless and / or electrolytic metallization. During industrial desmearing, the adhesion of exposed glass fillers on the substrate surface and recess surfaces weakens, resulting in loss or damage of their anchoring in the surrounding resin matrix. If these fillers are not removed, the remaining weakly bonded or loose fillers can lead to reduced adhesion of plated copper on the epoxy resin, and furthermore, deterioration of copper-to-copper connections in blind microvias or through-holes (THs). This can affect manufacturing yield and the reliability of the final product.

[0004] Common methods for overcoming glass filler contamination include fluoride etching solutions described in U.S. Patent Application Publication 2012 / 0298409 and ultrasonic treatment described in U.S. Patent Application Publication 2007 / 0131243. Neither of these strategies is readily applicable to the vertical mode of semi-additive processes (SAP). Serious health problems with fluoride etching solutions make them immediately unsuitable for most parts of the industry, while ultrasonic application in vertical mode, even in basket application, is extremely difficult to use in a homogeneous manner that has a sufficiently large impact on each panel.

[0005] Japanese Patent Publication No. 2010-229536 discloses a pretreatment agent for cleaning the surface of a resin substrate containing a silica-based filler, which removes the filler and glass fibers exposed on the substrate surface after desmearing or the like. The pretreatment agent comprises an alkali, a nonionic ether-based surfactant, and an amine-based complexing agent.

[0006] U.S. Patent Application Publication 2010 / 056416 discloses a cleaning composition having a limited number of natural raw materials, comprising an anionic surfactant, a hydrophilic compound selected from C6 alkyl polyglucosides, a nonionic surfactant, and a hydrophobic compound such as oleic acid or palmitic acid, wherein the composition has a pH of 7 to 13. The cleaning composition can be used to clean laundry, soft surfaces and hard surfaces.

[0007] In particular, in SAP applications that require metallization of the entire surface of a non-conductive substrate to initiate the SAP application, reliable substrate cleaning and plating cannot be achieved.

[0008] Setting aside the issues mentioned, which provide good cleaning and plating compositions for constantly emerging substrate materials and processing chemical techniques, the cleaning and plating processes must also be permanently adapted. For example, the desmear process requires increasingly longer time and more precautions for newer materials compared to subsequent process steps in pretreatment and metallization. In particular, good alternation from one part of the process series to another, or from one treatment bath to another, presents long-lasting problems throughout the metallization process of non-conductive materials, such as problems arising from the development of post-treatment material properties, different holding times, and processing times. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] U.S. Patent Application Publication No. 2012 / 0298409 [Patent Document 2] U.S. Patent Application Publication No. 2007 / 0131243 [Patent Document 3] Japanese Patent Publication No. 2010-229536 [Patent Document 4] U.S. Patent Application Publication No. 2010 / 056416 [Overview of the project] [Problems that the invention aims to solve]

[0010] Therefore, the present invention aims to overcome the shortcomings of the prior art and to provide an improved cleaning method, including the removal of loose glass filler from the non-conductive surface of various composites having an organic polymer and a glass filler, after drilling recessed structures with low adhesion, such as blind microvias or through-holes, in which the glass filler is exposed on the composite surface.

[0011] Furthermore, an object of the present invention is to provide a means for preparing a clean, non-conductive surface after drilling recessed structures as blind microvias, which enable improved peel strength results after metallization.

[0012] Another objective of the present invention is to provide an improved means of removing glass fillers, which improves the handling and flexibility of different process steps in the use of new treatment bath compositions.

[0013] Another objective of this invention is to improve the adsorption and homogeneous deposition of an activator as a palladium catalyst on the surface of a substrate, thereby providing a catalyst that enhances the adhesion of subsequent copper plating and improves the reliability of copper adhesion. At the same time, the consumption of the activator is kept as low as possible.

[0014] Another objective of the present invention is to use means for manufacturing electronic articles as a multilayer assembly as a fine-wire IC substrate, preferably based on SAP application. [Means for solving the problem]

[0015] These objectives are addressed using the present invention.

[0016] In one embodiment of the present invention, A method for cleaning the non-conductive surface of a non-conductive layer, wherein the non-conductive layer is based on a composite of an organic polymer and a glass filler and includes blind microvias (BMVs) for the fabrication of an article having an integrated circuit, the non-conductive surface includes the non-conductive wall surface of the BMV, the non-conductive layer is bonded to a copper layer, the copper layer forms the bottom of the BMV, and the following steps are taken: (i) A step of preparing the nonconductive surface of the nonconductive layer; (ii) To obtain a desmeared surface, the following steps are taken: a step of treating with a swelling agent solution containing water and an organic solvent, a step of treating with an aqueous etching solution containing an oxidizing agent, and a step of treating with an aqueous reducing solution containing a reducing agent, in this order, and a step of treating the prepared surface using a desmear process; (iii) A step of treating the surface treated in step (ii) with an aqueous alkaline cleaning solution to remove the glass filler, wherein the aqueous alkaline cleaning solution is: (a) at least one surfactant selected from the group consisting of saturated branched or unbranched C5-C12 carboxylic acids or salts thereof, wherein the concentration of (a) one surfactant is 0.9-1.7 g / L; (b) At least one surfactant selected from the group consisting of saturated branched or unbranched C5-C12 alkyl groups having a negatively charged group selected from sulfates, sulfites, sulfonates, phosphates, phosphates, and carbonates, and saturated C3-C8 alkylaminocarboxylates; (c) at least one compound selected from the group consisting of alkoxylated C5-C12 alkanols and glycoside C5-C12 alkanols, having at least one hydroxyl group and at least one COC group; and (d) A process involving alkali metal hydroxides with a concentration of 65-200 g / L; (iv) A step of drying the surface treated in step (iii) in order to obtain a dry surface, preferably a water-free surface. A method is provided that includes this.

[0017] In another aspect of the present invention, there is provided the use of the above method for SAP (semi-additive process) application in the fabrication of an article having an integrated circuit with line / space dimensions from 25 / 25 μm to 8 / 8 μm or less.

[0018] A further aspect of the present invention will be apparent to those skilled in the art from the dependent claims or the following description.

[0019] The features will become apparent to those skilled in the art by describing exemplary embodiments in detail with respect to the following accompanying drawings.

Brief Description of the Drawings

[0020] [Figure 1] The results of the cleaning performance of non-conductive surfaces by SEM are illustrated.

Modes for Carrying Out the Invention

[0021] Here, detailed reference is made to embodiments, examples of which are illustrated in the accompanying drawings. The effects and features of the exemplary embodiments, as well as the implementation methods thereof, will be described with reference to the accompanying drawings. In the drawings, like reference numerals denote like or similar elements, and duplicate descriptions are omitted. As used herein, the term "and / or" includes any combination of one or more of the associated listed items. Further, the use of "may be" when describing embodiments of the present invention refers to "one or more embodiments of the present invention".

[0022] In the following description of embodiments of the present invention, unless clearly indicated otherwise from the context, singular terms may include the plural, for example, when "filler" or "blind microvia" is used below, "a plurality of fillers" or "a plurality of blind microvias" are included.

[0023] In the following description, the terms “substrate” or “non-conductive surface of the substrate” will also be used for the sake of simplicity of reading. In this context, the substrate is made up of a non-conductive layer bonded to a copper layer, and the substrate has a non-conductive surface of the non-conductive layer that is treated according to the present invention, and a copper surface of the copper layer that also forms the bottom of blind microvias drilled into the non-conductive layer.

[0024] In the context of this invention, an aqueous solution is a solution containing more than 50% by mass of water.

[0025] In the context of the present invention, the oxidizing agent is suitable for oxidizing a compound or material, in particular, the non-conductive surface of a non-conductive layer to which the oxidizing agent is reduced. In other words, the oxidizing agent is a reducing agent in a redox chemical reaction, for example, a non-conductive surface, or more precisely, a substance that acquires, or "receives" / "accepts" electrons from the material of said surface.

[0026] In the context of the present invention, the reducing agent is suitable for reducing a compound, particularly a compound on a non-conductive surface of a non-conductive layer that is oxidized by the reducing agent. In other words, the reducing agent is a substance in a redox chemical reaction that donates electrons to a compound to be reduced by the reducing agent, such as a compound on a non-conductive surface.

[0027] The present invention is particularly suitable for use with a desmear treatment combined with a glass filler removal treatment, preferably prior to a pretreatment including palladium activation before treatment of a nonconductive surface according to the present invention, where the composite includes a glass filler as a spherical glass filler, for example, as part of an SAP base material. Using the present invention, it is possible to remove glass fillers exposed from a surface, including BMV and also through-hole (TH) walls, that have become loosely or less bonded during the drilling and desmear process, and to provide a treated surface that improves the adhesion of the subsequent deposited metal layer. The present invention provides a clean surface for a nonconductive layer, including the nonconductive walls of BMV and also TH, for subsequent electroless metallization processes and / or electrolytic metallization processes starting from a dry surface pretreatment.

[0028] In one embodiment, if the non-conductive surface also includes the wall surface of the TH, through holes are formed from the surface of the non-conductive surface to the surface of the copper layer.

[0029] The present invention makes it possible to separate the pretreatment process from the cleaning process, which includes the desmear process within a complete metallization process that is typically carried out in close succession to all single wet process steps in a wet series. This provides greater flexibility between these two key processes in terms of the longer time required for the desmear process and / or in terms of alternative bath compositions used for pretreatment.

[0030] This invention results in higher yield and better reliability of multilayer assemblies fabricated as printed circuit boards, and the adhesion of industrially important IC substrates and printed circuit board substrates exhibits significantly higher peel strength values ​​after processing using the new process.

[0031] The present invention particularly enables the fabrication of electronic articles having integrated circuits, such as IC substrate articles having line-to-space dimensions (L / S) of 25 / 25 μm to 8 / 8 μm, preferably 15 / 15 μm to 8 / 8 μm, or more preferably less than 8 / 8 μm. At the same time, the process provides excellent coating performance.

[0032] This invention uses less toxic components than those used in the prior art. Furthermore, this invention enables the manufacture of electronic articles under milder conditions in terms of working temperature and working time. This results in a substantial reduction in energy consumption and improved throughput. The low-temperature scheme also reduces equipment and maintenance costs.

[0033] One of the most desirable benefits of cleaning a non-conductive surface from loose glass fillers is increased adhesion of plated copper to the cleaned surface. The obvious reason to expect this increased adhesion is to assume that the "loose" glass filler has poor adhesion to the substrate. This must be the case with fillers that are less than half embedded in the surrounding epoxy resin after desmearing, or the case with fillers that have been re-adsorbed in some way. When copper is then plated around this filler and a peeling force is applied, they lift easily from the substrate. Surprisingly, the drying process further improves the adhesion of subsequent deposited metal layers and results in an improved distribution of activators while reducing the amount of activator density. The aforementioned effects are particularly helpful in saving funds and resources.

[0034] The present invention can be used in a wide variety of substrates from different suppliers, in which the nonconductive layer is based on a composite of an organic polymer and a glass filler, and the copper layer is bonded to the nonconductive layer, for example, by lamination that constructs the substrate to be treated.

[0035] The composite is based on a mixture of glass fillers and / or silica fillers with organic polymers as resins and / or plastics and blends thereof. The resins and plastics include dielectric materials commonly used in the electronics industry, which are to be metallized. The resins and plastics are preferably selected from epoxy, including epoxy resins, isocyanate resins, bismaleimidotriazine resins and phenylene resins; polyesters such as polyethylene terephthalate (PET), polyimides (PI), polytetrafluoroethylene, acrylonitrile-butadiene-styrene (ABS) copolymers, polyamides (PA), polycarbonates (PC), and mixtures and blends thereof.

[0036] The organic polymer more preferably comprises a polyimide resin or an epoxy resin, and the polyimide resin can be modified by adding polysiloxane, polycarbonate, polyester, etc. The epoxy resin may be a glass-filled epoxy board material comprising a combination of epoxy resin and glass filler, or a glass-filled epoxy board material with a high glass transition temperature, which is modified to have low thermal expansion and a high glass transition temperature.

[0037] Suitable glass fillers are preferably selected from borosilicate glass, quartz glass, silica glass, and fluorinated glass. The sizes of the various fillers range from 0.01 μm to 5 μm in diameter, preferably with an average diameter of 0.5 μm.

[0038] Preferably, the non-conductive layer composite is an integrated film, such as an epoxy-based material. Detailed names are provided as needed. The embedded glass filler has a diameter of an average of 0.5 μm and a maximum of 5.0 μm.

[0039] The substrate according to the present invention may include a core layer. In this case, the copper layer bonded to the nonconductive layer is further bonded to the core layer. This core layer makes the handling of the more flexible substrate easier and avoids unwanted twisting of the substrate.

[0040] In a further embodiment, two substrates can be bonded to a core layer. In this case, the copper layer of each substrate is bonded to the core layer, while the non-conductive layer is an outer layer. This allows the non-conductive layers of two substrates containing one core layer to be processed from both sides of the core layer, enabling the construction of a multilayer assembly.

[0041] The aforementioned core layer can be selected from the group consisting of printed circuit board substrates, circuit carrier substrates, interconnect device substrates, and precursors for any of the aforementioned. Such substrates and precursors include, among other things, NEMA grade flame retardant materials as FR-1, FR-2, FR-3, FR-4, FR-5 (FR-1, FR-2, FR-3, FR-4, and FR-5 are PCB dielectric materials with good electrical specifications known to those skilled in the art, manufactured, for example, from paper and phenol-formaldehyde resin (FR-1), woven / nonwoven glass fiber cloth impregnated with epoxy resin (FR-4), or glass fiber fabric reinforced with a high-temperature epoxy resin binder (FR-5)), copper-clad materials, SAP materials, IC substrates, and laminates thereof, and preferably the core layer is an FR4 material, an SAP material, or an IC substrate.

[0042] The desmear process in step (ii) is carried out before step (iii), preferably as a rinsing step, without any further wet chemical steps.

[0043] The desmear process includes substeps (t1), (t2), and (t3), (t1) includes treatment of the non-conductive surface of the non-conductive layer to obtain a swollen surface using a swelling agent solution containing water and an organic solvent on the non-conductive surface of the non-conductive layer, (t2) includes a swelling surface treatment to obtain an etched surface using an aqueous etching solution containing an oxidizing agent, (t3) includes treatment of the etched surface, which involves obtaining a desmeared surface using an aqueous reducing solution containing a reducing agent.

[0044] By applying the corresponding substeps (t1), (t2), and (t3), a particularly effective desmear process can be ensured, in which the main portion of the residue (so-called smear) originating from the drilling process is removed.

[0045] The swelling agent solution penetrates the non-conductive surface of the non-conductive layer that yields the swollen surface, further weakening the bonding strength of the (weakly) bound particles as glass fillers or the drilling residue within the surface. Preferably, the organic solvent of the swelling agent solution is selected as a glycol ether and / or lactam and penetrates the exposed resin surface of the through-holes and BMV. Most preferably, the solution is selected as a commercially available Securiganth MV Sweller (swelling agent).

[0046] Preferably, the organic solvent is applied to the water-containing swelling agent solution at a concentration of 300 ml / L to 650 ml / L, preferably 350 ml / L to 550 ml / L, and more preferably 450 ml / L to 550 ml / L, relative to the total volume of the swelling agent solution.

[0047] Preferably, the swelling agent solution has a pH of 9.5 to 12, preferably 10.5 to 11.5.

[0048] Preferably, (t1) is carried out at a temperature of 55°C to 90°C, preferably 70°C to 85°C, for a duration of 2 to 10 minutes, preferably 4 to 5 minutes.

[0049] The aqueous etching solution of (t2) may contain an oxidizing agent, more preferably hydrogen peroxide and sulfuric acid. Preferably, the aqueous etching solution is selected as an alkaline aqueous etching solution, more preferably a potassium hydroxide solution or a sodium hydroxide solution, and contains an oxidizing agent, more preferably potassium permanganate. Most preferably, the etching agent is selected as a commercially available Securiganth P500 or Securiganth MV P-Etch.

[0050] Preferably, the treatment using an aqueous etching solution containing (t2), preferably a permanganate, is applied at a concentration of 50 g / L to 70 g / L, preferably 55 g / L to 65 g / L, relative to the total volume of the aqueous etching solution.

[0051] Preferably, (t2) is carried out at a temperature of 70°C to 90°C for a duration of 5 to 25 minutes, preferably 8 to 15 minutes.

[0052] The aqueous reduction solution (t3) contains a reducing agent, preferably hydroxylammonium sulfate or hydrogen peroxide, and an acid, most preferably sulfuric acid or hydrochloric acid, which can reduce metal residues from the previous step. Optionally, the aqueous reduction solution (t3) may contain a reducing agent compound to obtain an aqueous reducing agent solution. The aqueous reducing agent solution preferably contains an acid such as sulfuric acid or hydrochloric acid, for example, a reagent capable of reducing manganese dioxide on the surface of a non-conductive surface after applying the aqueous etching solution of (t2), for example, hydroxylammonium sulfate or hydrogen peroxide, and a quaternary nitrogen atom-containing polymer. For example, Securiganth® MV Reduction Solution or Securiganth® MV Reduction Conditioner, available from Atotech Deutschland GmbH, can be used.

[0053] Preferably, (t3) is carried out at a temperature of 40°C to 55°C for a duration of 3 to 7 minutes.

[0054] Step (iii): The surface treated in step (ii) is treated with an aqueous alkaline cleaning agent solution.

[0055] By applying step (iii) after the desmear process, any remaining residue from the drilling process is removed, but more importantly, any loose glass filler is thoroughly removed.

[0056] The concentration of at least one surfactant (a) in the aqueous alkaline detergent solution is 0.9 to 1.7 g / L, preferably 1.0 to 1.5 g / L, and more preferably 1.2 to 1.4 g / L. If there are two or more surfactants in the solution, the total concentration is 0.9 to 1.7 g / L, preferably 1.0 to 1.5 g / L, and more preferably 1.2 to 1.4 g / L. It is understood that surfactants can be added as acids or salts.

[0057] The concentration of at least one surfactant (b) in the aqueous alkaline detergent solution is preferably 0.5 to 10 g / L, more preferably 1.5 to 9 g / L, and most preferably 2 to 8 g / L. Other preferred concentration ranges are 0.5 to 1.2 g / L, preferably 0.7 to 1.1 mg / L, and more preferably 0.75 to 1.0 g / L. If there are two or more surfactants in the solution, the total concentration is also 0.5 to 10 g / L. In a preferred embodiment, the concentration range of at least one surfactant (b) selected from the group consisting of saturated branched or unbranched C5 to C12 alkyls having a negatively charged group selected from sulfates, sulfites, sulfonates, phosphates, phosphates, and carbonates is 0.5 to 1.2 g / L, preferably 0.7 to 1.1 mg / L, and more preferably 0.75 to 1.0 g / L. In another preferred embodiment, the concentration range of at least one surfactant (b) selected from the group consisting of saturated C3-C8 alkylaminocarboxylic acids is 0.5-10 g / L, preferably 1.5-9 g / L, and more preferably 2-8 g / L.

[0058] The concentration of at least one compound (c) having at least one hydroxyl group and at least one COC group in the aqueous alkaline detergent solution is preferably 0.7 to 1.3 g / L, more preferably 0.8 to 1.2 g / L, and most preferably 0.9 to 1.1 g / L. In the case of two or more alkanols in the solution, the total concentration is also 0.7 to 1.3 g / L, preferably 0.8 to 1.2 g / L, and more preferably 0.9 to 1.1 g / L.

[0059] (d) Concentration of alkali metal hydroxide results in a strongly alkaline pH value, which is calculated to be higher than pH 14. The concentration of (d) alkali metal hydroxide in the aqueous alkaline cleaning agent solution is used at 65 to 200 g / L, preferably 70 to 100 g / L, and more preferably 75 to 90 g / L.

[0060] Throughout this specification and the claims, it should be noted that the scope of disclosure and numerical limits of ratios may be combined and are intended to include all intermediate values. Furthermore, all numerical values ​​are intended to be preceded by the modifier "approximately," whether or not this term is specifically stated.

[0061] At least one surfactant is selected from the group consisting of saturated branched or unbranched C5-C12 carboxylic acids or salts thereof, preferably saturated branched C6-C10 carboxylic acids or salts, preferably hexanoic acid, octanoic acid and decanoic acid or salts thereof, most preferably hexanoic acid and octanoic acid or salts thereof. The surfactant selected from the group consisting of saturated unbranched C6-C10 carboxylic acids or salts, more preferably saturated unbranched C6-C8 carboxylic acids or salts, is preferably unsubstituted hexanoic acid and octanoic acid.

[0062] At least one surfactant selected from the group consisting of saturated branched or unbranched C5-C12 alkyl groups having a negatively charged group selected from sulfate, sulfite, sulfonate, phosphate, phosphite, and carbonate is preferably selected from the group consisting of saturated branched or unbranched C5-C12 alkyl groups having a negatively charged group of sulfate, phosphate, and carbonate, and more preferably from the group consisting of saturated branched or unbranched C5-C8 alkyl groups having a negatively charged group of sulfate, such as n-pentyl, isopentyl, n-hexyl, 2-ethylhexyl, n-heptyl, or n-octyl, and the surfactant is most preferably sodium 2-ethylhexyl sulfate or sodium isoheptyl sulfate.

[0063] The positive counterion of a saturated branched or unbranched C5-C12 alkyl group having a negatively charged group is preferably sodium or potassium, more preferably sodium.

[0064] Saturated C3-C8 alkylaminocarboxylates are preferably of formula (III) or (IV)

[0065] [ka]

[0066] [In the formula, R is a branched or unbranched C4-C8 alkyl group, such as n-pentyl, isopentyl, n-hexyl, 2-ethylhexyl, n-heptyl, or n-octyl.] or

[0067] [ka]

[0068] [In the formula, k is an integer between 3 and 8, preferably between 4 and 6, most preferably an integer of 6.] It is a compound of [the compound].

[0069] The surfactant is understood to be added preferably as a salt. The positive counterion of the saturated C3-C8 alkylaminocarboxylate is preferably sodium or potassium, more preferably sodium.

[0070] At least one compound (c) is selected from the group consisting of alkoxylated C5-C12 alkanols and glycoside C5-C12 alkanols.

[0071] The alkoxylated C5-C12 alkanol of compound (c) is preferably of formula (I)

[0072] [ka]

[0073] The compound is [wherein p is an integer between 1 and 2, o is an integer between 4 and 10, m is an integer between 4 and 9, more preferably p is 1, o is 5 to 7, and m is 5 to 7]. Most preferably, the alkoxylated C5-C12 alkanol is ethoxylated hexanol or ethoxylated octanol in which o is 6.

[0074] The average molecular weight (MW) of the compound of formula (I) is 200 to 15,000 g / mol, preferably 400 to 1,000 g / mol, and most preferably 300 to 600 g / mol.

[0075] The glycoside C5-C12 alkanol of compound (c) is preferably of formula (II)

[0076] [ka]

[0077] The compound is [wherein n is an integer from 1 to 5, and m is an integer from 4 to 9, preferably from 5 to 7]. Preferably, the compound is an alkyl polyglucoside (APG) provided by CAS 54549-24-5.

[0078] Preferably, the alkali metal hydroxide is sodium hydroxide or potassium hydroxide, more preferably sodium hydroxide.

[0079] In a preferred embodiment, the aqueous alkaline detergent solution of the present invention comprises (a) at least one surfactant selected from the group consisting of hexanoic acid and octanoic acid or salts thereof; (b) at least one surfactant selected from the group consisting of sodium ethylhexyl sulfate (sodium ethasulfate), sodium isoheptyl sulfate, and alkylaminocarboxylate according to formula (III) [wherein R is 2-ethylhexyl or n-octyl] and formula (IV) [wherein k is 4 to 6]; (c) at least one compound selected from the group consisting of alkoxylated C5-C12 alkanols which are compounds of formula (I) [wherein the compound is ethoxylated hexanol, ethoxylated octanol, or ethoxylated decanol, where o is 6] and glycoside C5-C12 alkanols which are compounds of formula (II) [wherein n is an integer from 1 to 5 and m is an integer from 5 to 7]; and (d) sodium hydroxide. In a more preferred embodiment, the aqueous alkaline cleaning agent solution of the present invention further comprises (e) at least one water-soluble alkanolamine.

[0080] In a more preferred embodiment, the aqueous alkaline cleaning agent solution of the present invention comprises a combination of (b) sodium ethasulfate and (c) ethoxylated hexane-1-ol; (b) 1-aminohexyl carboxylate and (c) ethoxylated decane-1-ol; or (b) APG and (c) 2-ethylhexyl iminodipropionate. Preferably, these combinations are used together with (a) hexanoic acid and (d) sodium hydroxide. In a further more preferred embodiment, the aforementioned combinations are used together with monoethanolamine. Most preferably, the aqueous alkaline cleaning agent solution of the present invention comprises the aforementioned combinations.

[0081] Preferably, the aqueous alkaline cleaning agent solution further comprises (e) at least one water-soluble alkanolamine selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA), preferably 2-aminoethanol. By using a water-soluble alkanolamine, clouding of the solution can be avoided. Our own experiments have shown that cloudy solutions result in undesirable plating results.

[0082] The concentration of at least one water-soluble alkanolamine is 6.5 to 9.0 g / L, preferably 7.5 to 8.5 g / L, and more preferably 7.8 to 8.2 g / L.

[0083] The method can be used in vertical and horizontal plating equipment. Preferably, the method is used in vertical plating equipment, where the substrate is transported by a transport device and processed through the processing module of the plating equipment.

[0084] The method of the present invention is preferably used when (iii) the treatment is carried out at 55-65°C for 3-7 minutes. Low temperatures reduce energy consumption and also reduce equipment costs for using higher temperatures. In addition, evaporation of low-boiling point components can be prevented and strong suction can be avoided.

[0085] In a preferred embodiment of the method of the present invention, step (iv) is carried out at a temperature of 80°C to 100°C for 5 to 20 minutes, preferably at a temperature of 85°C to 95°C for 10 to 15 minutes, to obtain a dry surface. The drying step can be carried out, for example, by infrared heating, conventional heating, heated air blowing, or a combination thereof.

[0086] To avoid undesirable chemical or physical reactions and consequently achieve the best results for subsequent processing steps, it is important that the surface is dry, preferably water-free. The drying process, surprisingly, allows for the postponement of subsequent processing steps without damaging, degrading, or destroying the non-conductive surface during waiting, or for the entire process to be stopped for a specific period before starting subsequent processing steps. This is particularly useful when the desmear process is to be carried out separately (locally and / or as needed), due to the various requirements for chemical phenomena and / or the necessary process time. The separation can be carried out for various processing modules, one for cleaning and one for pretreatment.

[0087] In one embodiment, the method of the invention further includes an additional step (vi) in which the surface of step (iv) is treated with an aqueous alkaline cleaning solution containing ethanolamine after step (iv). This step may be carried out within a cleaning module, a standalone module, or a pretreatment module corresponding to a subsequent process step. If step (vi) is carried out within a cleaning module or a standalone module, it may be omitted from pretreatment step (v) to (ix) below.

[0088] Therefore, the method of the invention can be used as a first part of a metallization process of a non-conductive surface, including cleaning, pretreatment, and metallization. The method of the invention is preferably used before activating a non-conductive surface by using a palladium activator solution for subsequent metallization, for example, to produce an integrated circuit, such as an article having a multilayer assembly, such as a fine-wire IC substrate article.

[0089] Therefore, the method may, in non-limiting embodiments, preferably further include a step of pre-treating the surface after step (iv) in order to prepare the surface for subsequent electroless and / or electrolytic metallization, and further steps: - An optional step (v) in which the surface of step (iv) is treated with an aqueous alkaline cleaning solution containing ethanolamine; - Step (vi) involves treating the surface of step (v) with an aqueous etching cleaning solution containing persulfate; - Step (vii) involves treating the surface of step (vi) with a pre-immersion solution; - Preferably, step (vii) involves treating the surface of step (vii) with an activator solution containing noble metal ions, metal colloids, or carbon-containing compounds; and - If the activator solution contains noble metal ions, the surface of step (vii) is treated with a reducing agent solution in step (ix). It is included in this order.

[0090] Step (v) can be omitted if it has already been performed.

[0091] In another embodiment of the present invention, step (v) is optional. In a preferred embodiment, step (v) is performed to further improve the subsequent metallization result.

[0092] Step (v) is preferably carried out at 50-70°C for 3-7 minutes. In a preferred embodiment, the detergent comprises 10-20 g / L of sodium hydroxide and 10-16 g / L of ethanolamine (MEA).

[0093] Step (vi) is preferably carried out at 25-40°C for 1-2 minutes. In a preferred embodiment, the detergent contains 100-150 g / L of sodium persulfate and 30-45 g / L of sulfuric acid.

[0094] An optional step (vii) to treat the surface of step (vi) using a pre-soaking solution. The pre-soaking solution is preferably an aqueous solution containing sulfuric acid and / or sodium bisulfate and a nonionic surfactant, preferably a pH adjuster. The nonionic surfactant is preferably a polyethylene glycol (PEG) compound, more preferably PEG 1500 MW or PEG 10,000 MW.

[0095] The pre-immersion solution is preferably an acidic aqueous pre-immersion solution. The preferred pH is 2 to 4.

[0096] Step (viii) involves treating the surface of step (vii) with an activating solution preferably containing a noble metal ion, a metal colloid, or a carbon-containing compound. The activating solution is preferably an aqueous solution containing a noble metal ion or a metal colloid. The activating solution is applied to the surface of the non-conductive layer, preferably with an aqueous palladium activating solution, and the palladium ion layer is deposited on the surface of the non-conductive layer of step (viii). Other useful activating solutions known in the art may contain carbon, a conductive polymer, or a metal colloid containing, for example, copper or palladium-tin, for subsequent electrolytic direct metallization.

[0097] The palladium activator solution contains at least one palladium ion source. Additionally, the solution may contain other metal ion sources as mixtures thereof, including ruthenium ion sources, rhodium ion sources, palladium ion sources, osmium ion sources, iridium ion sources, platinum ion sources, copper ion sources, silver ion sources, nickel ion sources, cobalt ion sources, gold ion sources, and other metal ion sources. The palladium ions and the additional metal ions are adsorbed on the surface of the substrate.

[0098] (ix) A step of processing the substrate of step (viii) in which a palladium activator solution is used together with a palladium reducing solution, wherein the deposited palladium ion layer of step (viii) is converted into a metallic palladium layer.

[0099] Treatment of the substrate surface containing at least palladium ions is carried out using a palladium reduction solution containing at least one reducing agent suitable for reducing metal ions (at least palladium ions) adsorbed on the substrate surface to a metallic state, selected from the group consisting of boron-based reducing agents, hypophosphite ion sources, hydrazine and hydrazine derivatives, ascorbic acid, isoascorbic acid, formaldehyde sources, glyoxylic acid, glyoxylic acid sources, glycolic acid, formic acid, sugars, and salts of the aforementioned acids.

[0100] The method of the invention further comprises, after step (viii) or (ix), a step (x) for electroless metallization of a surface and / or a step (xi) for electrolytic metallization, in order to obtain a metallized surface, preferably a copper surface. Step (x) is carried out using an electroless copper plating bath to obtain a copper layer on top of the layer of step (ix).

[0101] Generally, an electroless plating bath comprises a solvent, typically water, and at least one source of metal ions to be deposited. Further optional components include complexing agents (or chelating agents) for the metal ions (e.g., those described below), reducing agents, stabilizers, cosolvents, wetting agents, and functional additives such as brighteners, accelerators, inhibitors, and anti-coloring agents. Such baths and components are known in the art. An electroless copper plating bath may further include a nickel ion source, a cobalt ion source, and mixtures thereof.

[0102] To obtain a copper or nickel layer on the surface while filling the BMV with copper or nickel, electrolytic metallization of the surface in step (xi) is performed after step (viii) using an electrolytic copper or nickel plating bath (if a layer of carbon or conductive polymer is deposited on the surface in step ((vi) or (vii))). The copper or nickel layer may be a copper alloy or nickel alloy containing alloying metals such as tungsten or silver.

[0103] If necessary, additional steps may be performed between the above steps, such as rinsing with DI water, or an acidic or alkaline aqueous solution; an etching cleaning agent step; a pre-immersion step; and / or a drying step.

[0104] Except for the solution of the present invention in the above-described process, the bath compositions and solutions themselves used are well known in the art. Suitable solutions for the desmear process, palladium activator solutions, palladium reducing solutions, electroless and electrolytic copper solutions are known and can be purchased, for example, from Atotech Deutschland GmbH as Securiganth® MV Cleaner PF, Neoganth® MV Etch Cleaner, Neoganth® MV Activator, Neoganth® MV Reducer, Printoganth® MV, and Cupracid® AC.

[0105] In a preferred embodiment of the present invention, the electroplating bath in step (xi) is an electroplating copper bath for obtaining a copper layer. The substrate obtained as a result of step (xi) can be used to construct a multilayer assembly by using the following steps of SAP application.

[0106] In one embodiment, the copper layer of step (xi) can be structured by known process steps including photoresist coating, structuring, patterning, photoresist stripping, and final etching to the surface of the nonconductive layer in order to obtain a conductive structure on the nonconductive layer.

[0107] The present invention is illustrated here by reference to the following figures and non-limiting embodiments. [Examples]

[0108] The relative ratios of the compounds used in the examples of the present invention were found to be useful and preferable, but are not considered limiting. All components of the reagent were diluted with DI (DI - deionized water).

[0109] Three sets of test examples—samples 1, 2, 3, 4, 5, 6, 9, and 10 (examples of the invention—samples 5 and 6, and comparative examples—samples 1, 2, 3, 4, 9, and 10) were prepared.

[0110] All test specimens (samples) were treated according to the desmear process (t1-t3), and (t3) was performed with a modifier (samples 1, 3, 5, and 9) and without a modifier (samples 2, 4, 6, and 10) according to the following scheme:

[0111] [Table 1]

[0112] Examples of the invention (Example 1 of the invention (samples 5 and 6)) were treated with an aqueous alkaline cleaning agent solution having a solution temperature of 60°C and a residence time of 5 minutes (step (iii)), and dried at 90°C for 15 minutes according to step (iv).

[0113] Comparative examples (samples 1 and 2) were processed without step (iii), but were dried at 90°C for 15 minutes according to step (iv).

[0114] Comparative examples (samples 9 and 10) included step (iii), but without drying in step (iv).

[0115] Comparative examples (samples 3 and 4) were treated using step (iii), but were dried at 90°C for 15 minutes prior to step (iii).

[0116] Example 1 of the invention using the aqueous alkaline cleaning agent solution of step (iii) (Samples 5, 6) Solution concentration: Hexanoic acid 1.4 g / L Sodium ethasulfate 0.8g / L Ethoxylated hexane-1-ol (Cas 31726-34-8) 1.1 g / L Sodium hydroxide (NaOH) 84g / L MEA - Monoethanolamine (>98%) 6.5g / L

[0117] 1. Visual inspection by the naked eye To evaluate the glass filler removal performance, a set of test examples was used to take SEM images. These are shown in Figure 1. (SEM images, magnification = 5000x, showing the non-conductive surface of the non-conductive layer) (Samples 1, 2, 3, 4, 5, 6, 9, 10).

[0118] The cleaning results for samples 1 and 2 were very insufficient, showing that a significant amount of glass filler remained on the surface. Samples 3 through 9 all used process (iii), and thus show comparable good cleaning results in contrast to samples 1 and 2. However, the best cleaning results were achieved for samples 5 and 6, with slightly more glass filler removed compared to samples 3, 4, 9, and 10.

[0119] 2. Plating results Two sets of test examples were used to further process samples 1, 2, 3, 4, 5, 6, 9, and 10 according to the following scheme by step (v)-(x):

[0120] [Table 2]

[0121] After step (ix), a set of test example samples 1, 2, 3, 4, 5, 6, 9, and 10 are administered [μg / dm³]. 2 This method was used to determine the palladium loading level on the surface of the palladium. The results can be seen in Table 1.

[0122] After step (x), a set of test example samples 1, 2, 3, 4, 5, 6, 9, and 10 are administered [μg / dm³]. 2 This method was used to determine the palladium loading level on the surface of the palladium. The results can be seen in Table 1.

[0123] [Table 3]

[0124] Table 1 shows that the highest peel strength results were achieved for samples 5 and 6. Interestingly, these results were achieved even with the lowest level of palladium loading on the surface. This saved palladium consumption while improving reliability through better peel strength.

Claims

1. A method for cleaning the non-conductive surface of a non-conductive layer, wherein the non-conductive layer comprises a composite of an organic polymer and a glass filler, comprises blind microvias (BMVs) for the fabrication of an article having an integrated circuit, the non-conductive surface comprises the non-conductive wall surface of the BMV, the non-conductive layer is bonded to a copper layer, the copper layer forms the bottom of the BMV, and the following steps are taken: (i) A step of preparing the nonconductive surface of the nonconductive layer; (ii) The following steps: (t1) a step of treating with a swelling agent solution containing water and an organic solvent; (t2) a step of treating with an aqueous etching solution containing an oxidizing agent; and (t3) a step of treating with an aqueous reducing solution containing a reducing agent, in this order, a step of treating the surface prepared using a desmear process; (iii) A step of treating the surface treated in step (ii) with an aqueous alkaline cleaning solution to remove the glass filler, wherein the aqueous alkaline cleaning solution is: (a) at least one surfactant selected from the group consisting of saturated branched or unbranched C5-C12 carboxylic acids or salts thereof, wherein the concentration of (a) one surfactant is 0.9 to 1.7 g / L; (b) At least one surfactant selected from the group consisting of saturated branched or unbranched C5-C12 alkyl groups having a negatively charged group selected from sulfates, sulfites, sulfonates, phosphates, phosphates, and carbonates, and saturated C3-C8 alkylaminocarboxylates; (c) at least one compound selected from the group consisting of alkoxylated C5-C12 alkanols and glycoside C5-C12 alkanols, having at least one hydroxyl group and at least one COC group; and (d) A process involving alkali metal hydroxides with a concentration of 65 to 200 g / L; (iv) A step of drying the surface treated in step (iii) in order to obtain a dry surface Methods that include...

2. The method according to claim 1, wherein the process in step (iii) is carried out at 55 to 65°C for 3 to 7 minutes.

3. The method according to claim 1, wherein step (iv) is carried out at a temperature of 80°C to 100°C for 5 to 20 minutes.

4. After step (iv), in order to prepare the surface for subsequent electroless and / or electrolytic metallization, - The method according to claim 1, further comprising an additional step (v) of treating the surface of step (iv) with an aqueous alkaline cleaning agent solution containing ethanolamine.

5. The aforementioned method is: - Step (vi) of treating the surface of step (v) with an aqueous etching cleaning solution containing persulfate; - Step (vii) of treating the surface of step (vi) using a pre-immersion solution; - Step (viii) of treating the surface of step (vii) with an activator solution; and - If the activating agent solution contains noble metal ions, step (ix) of step (vii) is performed by treating the surface with a reducing agent solution. The method according to claim 4, further comprising:

6. The method according to claim 5, further comprising, after step (viii) or (ix), a step (x) for electroless metallization of the surface and / or a step (xi) for electrolytic metallization of the surface, in order to obtain a metallized surface.

7. The method according to claim 1, wherein the nonconductive layer bonded to the copper layer constructs a substrate having the nonconductive surface of the nonconductive layer and the copper surface of the copper layer.

8. The method according to claim 1, wherein the copper layer bonded to the nonconductive layer is further bonded to the core layer.

9. The method according to claim 1, wherein (b) at least one surfactant is used at a concentration of 0.5 to 10 g / L, and / or (c) at least one compound is used at a concentration of 0.6 to 1.3 g / L.

10. The method according to claim 1, wherein (a) at least one surfactant is selected from the group consisting of saturated branched C6-C10 carboxylic acids or salts.

11. The method according to claim 1, wherein (b) at least one surfactant is selected from the group consisting of saturated branched or unbranched C5-C8 alkyl groups having negatively charged sulfate, phosphate, and carbonate groups, and saturated C5-C8 alkylamine carboxylates.

12. (c) The above, at least one compound is of formula (I) 【Chemistry 1】 [In the formula, p is an integer between 1 and 2, o is an integer between 4 and 10, and m is an integer between 4 and 9] is an alkoxylated C5-C12 alkanol. (c) The above, at least one compound is of formula (II) 【Chemistry 2】 The method according to claim 1, wherein the glycoside C5-C12 alkanol is [wherein n is an integer from 1 to 5 and m is an integer from 4 to 9].

13. The method according to claim 1, wherein the aqueous alkaline cleaning agent solution further comprises (e) at least one water-soluble alkanolamine, and the (e) at least one water-soluble alkanolamine is selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA).

14. The method according to claim 13, wherein the concentration of at least one water-soluble alkanolamine in (e) is 6.5 to 9.0 g / L.

15. Use of the method according to any one of claims 1 to 14 for the application of SAP (semi-additive process) in the manufacture of electronic articles having integrated circuits having line / space dimensions of 75 / 75 μm to 8 / 8 μm or less.

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