Quality control method for manufacturing component career, and reducer composition

Abstract

To provide a method for controlling the quality of physical properties of a conductive material structure formed on a component career by a lamination molding process, especially an electroless process in each component career manufacturing process.SOLUTION: A lamination molding process comprises using a reducer having the composition and / or quantity and / or specific electrical properties of a specific contaminant. The method comprises the steps of: estimating, especially determining i) the following: ia) the existence of physical properties and / or ib) the composition and / or quantity and / or specific electrical properties of the specific contaminant of the reducer; and changing the composition of the reducer or the reducer when exceeding a threshold value obtained by setting ii) the following: iia) the estimated physical properties and / or iib) the composition and / or quantity and / or specific electrical properties of the specific contaminant of the reducer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for controlling the quality of physical features of conductive material structures formed on a component carrier by an additive manufacturing process during the respective component carrier manufacturing process. The present invention further relates to a reducing agent composition for such an additive manufacturing process for forming conductive material structures on a component carrier.

[0002] The invention may therefore relate to the technical field of component carriers such as printed circuit boards or IC boards and their manufacture. [Background technology]

[0003] In the context of improving product functionality of component carriers carrying one or more electronic components, and the increasing miniaturization of such electronic components, as well as an increasing number of electronic components mounted on component carriers such as printed circuit boards, increasingly powerful array-like components or packages are being utilized that carry several electronic components, which have multiple contacts or connections with ever-smaller spacing between these contacts. Removing heat generated by such electronic components and the component carrier itself during operation is becoming an increasingly important issue. Efficient protection against electromagnetic interference (EMI) is also becoming an increasingly important issue. At the same time, component carriers must be mechanically robust and electrically and magnetically reliable to operate under harsh conditions.

[0004] In this context, providing a high quality conductive layer structure on a component carrier can still be considered a challenge.

[0005] The conductive layer structure can be formed during component carrier manufacture, for example, by electroplating. Furthermore, the conductive layer structure can also be formed (at least in part) by an electroless process, for example, a seed layer for a subsequent electroplating process can be deposited by an electroless process. For example, an electroless process can include the deposition of a conductive copper layer on the surface of an organic insulating material (e.g., ABF).

[0006] However, electroless (copper) deposition can be associated with several drawbacks, including a high defect rate. For example, physical features such as bumps, nodules, and protrusions can be observable in the conductive material. Additionally, physical features can include observable variations in the conductive material, such as changes in color, crystalline structure, or thickness. Typically, such irregularities adversely affect the performance of the final component carrier.

[0007] 1A to 1E show a method for manufacturing a component carrier 100 using an electroless process.

[0008] 1A: A component carrier preform is provided having an electrically insulating layer structure 102 and an electrically conductive layer structure 104. It can be seen that the upper major surface of the electrically insulating layer structure 102 has foreign matter 110 from the process chemistry (e.g., particles, anything that interferes with the plating process (electric field)) attached thereto.

[0009] 1B: An electroless process is used to deposit a copper layer 120 on the upper major surface of the electrically insulating layer structure 102. This causes the foreign particles 110 to be covered by the copper layer 120.

[0010] FIG. 1C: A mask pattern 125 is provided for the plating process in the subsequent steps.

[0011] FIG. 1D: The plating process takes place (illustrated by the anodic current).

[0012] FIG. 1E: The plating process provides conductive structures 130 between the mask patterns 125. However, nodules / bumps are formed on the foreign particles 110, resulting in an uneven copper surface. The presence of foreign particles 110 causes more copper to plate at these locations (peaking effect). These foreign particles 110 can absorb metals such as Pd, Ni, and then generate nodules. The nodules can cause a peaking effect in the electroplating process, resulting in copper bumps / nodules or uneven surface traces.

[0013] 2A-2E show a method for manufacturing a component carrier using an electroless process. This method is similar to that described in FIGS. 1A-1E, except that particles (some metal elements) from the original process chemistry and / or manufacturing environment result in protrusions 150. This is also based on the peak effect (higher copper plating) due to metal ion conductivity. Analysis has revealed the presence of some metals (such as Pb, Fe, and Al) that are originally present in the chemistry or originate from the chemical manufacturing environment.

[0014] For example, metals react with other chemicals in the tanks before and inside the Eless tank, thus producing metallic substances. These metallic substances have higher conductivity on the Eless surface, so there may be a peak plating effect with a higher plating rate in the contaminated area. This may result in protrusions on the surface, as can be seen in the figure. These metallic substances are usually not detectable in solid products, but are (easily) detectable in liquids.

[0015] 3A and 3B each show a microscope image of a conductive structure 130 (deposited by electroless plating) having a physical feature defect 150, here a nodule, after an electroless plating process.

[0016] 4A and 4B each show a microscope image of the conductive layer structure 130 (deposited by electroless plating) with an additional physical feature defect 150, here a nodule, after the plating process.

[0017] As explained above, such defects can significantly degrade the quality and / or performance of the final component carrier product, however, in many cases it may not be clear how each defect arises during manufacturing. Summary of the Invention

[0018] There may be a need to provide conductive material structures for component carriers in an efficient and reliable manner.

[0019] Methods and reducing agent compositions are described.

[0020] According to a first aspect of the present invention, a method is described for controlling the quality of physical features (e.g., color variations, protrusions, nodules, etc.) of conductive material structures (e.g., metal traces, seed layers, etc.) formed on a component carrier by an additive manufacturing process (in particular an electroless process) during a respective component carrier manufacturing process.

[0021] The additive manufacturing process involves the use of a reducing agent (in process chemistry, for example, formaldehyde), said reducing agent having a specific contaminant composition and / or amount and / or specific electrical characteristics (for example electrical conductivity), said method comprising: i) Below ia) the presence of physical features (e.g. by optical inspection) and / or ib) the composition and / or amount of specific contaminants and / or specific electrical characteristics of said reducing agent; estimating (in particular determining); and (then) ii) Below iia) estimated physical characteristics and / or iib) the composition and / or amount of specific contaminants and / or specific electrical characteristics of said reducing agent If the set threshold is exceeded, This includes changing the composition of the reducing agent or the reducing agent itself.

[0022] According to a second aspect of the present invention, a reducing agent composition for an additive manufacturing, in particular electroless, process for forming conductive material structures on a component carrier (for example as described above) is described, the reducing agent composition comprising at least one reducing agent (in particular at least two) i) particles other than the total composition of reducing agent, having an amount of less than or equal to 6000 particles / mL for particles having a size up to 0.5 μm; ii) metal particles (especially Fe, Pb, Cr, Zn particles) in an amount of less than 1 mg / L (especially less than 1 ppm; e.g., at least one of Fe, Pb, Cr, Zn); iii) organic particles, particularly in an amount such that a UV-visible absorption spectrometer scan within a wavelength range of 190 to 350 nm gives a curve deviation of less than 1 relative to the reducing agent without the organic particles; and iv) Electrical conductivity of less than 25 μS / cm At least one reducing agent (in particular at least two) having the formula:

[0023] In this context, the term "component carrier" may refer to a component carrier preform (i.e., a component carrier in production, in other words, a semi-finished product) as well as a final component carrier product. In one example, a component carrier preform may be a panel that includes multiple semi-finished component carriers manufactured together. At a final stage, the panel may be separated into multiple final component carrier products.

[0024] In one embodiment, a component carrier "stack" comprises at least one electrically insulating layer structure and at least one electrically conducting layer structure. For example, the component carrier may be a stack of the aforementioned electrically insulating layer structures and electrically conducting layer structures, formed in particular by applying mechanical pressure and / or thermal energy. The aforementioned stack may provide a plate-shaped component carrier that can offer a large mounting surface for further components. In one example, the stack may nevertheless be very thin and compact. In another example, the stack may be very thick for high-density products. The stacking direction (height / thickness) may be arranged in the vertical direction z. Furthermore, the stacking direction may be perpendicular to the two main extension directions (along x and y) of the (plate-shaped) component carrier.

[0025] In one example, all layers of a component carrier may form a stack. In another example, only some layers of a component carrier may form a stack. In this context, the term "layer structure" may refer, among other things, to continuous or discontinuous layers (or coplanar isolated islands) of electrically conductive or electrically insulating material. Multiple such layers may be stacked parallel to one another to form a stack in the vertical direction.

[0026] In this context, the term "conductive material structure" may refer to a conductive structure (e.g., at least one of a metal, in particular copper, a copper pattern, more particularly copper foil, or gold, nickel, palladium, tin, or carbon, in particular graphene, e.g., layered). Such a conductive structure may be a continuous layer or a discontinuous layer (e.g., patterned). A patterned conductive structure may, for example, include a plurality of conductive (metal, e.g., copper) traces and / or pads and / or interconnect structures and / or conductive paths / regions. In this way, electrical connections within the component carrier may be provided.

[0027] In this context, the term "physical feature" may refer to an observable / structural characteristic of a conductive material (structure). In one embodiment, such physical feature may be an undesired feature and / or defect. For example, the physical feature may be a protrusion, a nodule, or a bump or an overplated structure or residual structure. Furthermore, the physical feature may refer to a change in the conductive material, such as a change in color, a change in crystal structure, a change in material composition, a change in surface energy, a change in roughness, a change in thickness, a change in shape, a change in material amount, or a change in size. In one embodiment, these physical features may be caused by process parameters, such as process chemistry.

[0028] In this context, the term "composition and / or amount of a particular contaminant" may actually refer to an undesired material composition. In other words, substances that are undesired in a particular chemical agent (especially a reducing agent) may be considered as contaminants. Such contaminants may be metals (ions), organic substances, foreign bodies, droplets, gas bubbles, etc. A chemical agent may be characterized by its composition and / or the amount of (different types of) contaminants. Contaminants may be, for example, polymers or polar compounds. The concentration of the contaminants may be, for example, <1 mg / L and / or <1 ppm / L.

[0029] In one example, the contaminant may be an impurity of the chemical agent (such as a by-product of the reaction that forms the chemical agent). Typically, the chemical agent may have 10% or less impurities, particularly 3% or less. The contaminant may come from a reactor (a source of metal ions / particles) that may have corroded and / or parts of the sealing that may have dissolved. The contaminant may also be a stabilizer (which generally includes additives) that needs to be added to improve shelf life. Different types of contaminants may be, for example, metal ions and / or organic compounds, which may combine to form metal complexes.

[0030] In this context, the term "specific electrical characteristics" may refer to properties of a chemical agent that are related to its electrical properties. An example may be the electrical conductivity of the chemical agent. For example, a high concentration of metal ions (as contaminants) may increase the electrical conductivity.

[0031] In this context, the term "reducing agent" (reductant) may refer to a chemical agent / species / compound that donates electrons to another chemical species in a chemical reaction. The reducing agent loses electrons and is thus oxidized, while the reaction partner (e.g., oxidizing agent) gains electrons and is reduced. For example, a reducing agent can remove unwanted substances such as metal oxides or impurities by reducing them. Examples of reducing agents include formaldehyde, hydrogen, hydrazine, sodium bisulfite, and hydrochloric acid. Generally, a reducing agent has a lower electrochemical potential than the reaction partner (to be reduced). According to an exemplary embodiment, the present invention may be based on the idea that investigating the presence of physical characteristics (defects) of a component carrier and / or the composition / amount of specific contaminants and / or specific electrical characteristics of a reducing agent applied in a manufacturing process of a conductive material structure, and then, based on the investigation, modifying the composition of the reducing agent or the reducing agent (itself) can provide a conductive material structure for a component carrier in an efficient and reliable manner.

[0032] Reducing agents are commonly used in component carrier manufacturing, for example, to remove metal oxides, residues, and impurities during manufacturing. Typically, such reducing agents are purchased from a supplier. Thus, the inventors have surprisingly discovered that the chemical composition of the reducing agent can contain the composition / amount of specific contaminants that can directly lead to the presence of physical features in the conductive material structure.

[0033] Based on this insight, the inventors have discovered that the cause of many defects (physical characteristics such as copper color change) can be caused by contaminants in the reducing agent during component carrier manufacturing. Therefore, the presence of the physical characteristics and / or the properties of the applied reducing agent can be (continuously) monitored. If expected thresholds are not met, a change in the reducing agent (composition) can be initiated.

[0034] In the described method, the quality of the conductive material structure (and the performance of the final component carrier product) can be significantly improved. The described method can be implemented in an easy manner in existing production lines.

[0035] Furthermore, the present inventors have developed an optimal reducing agent composition that can be directly and efficiently applied to component carrier manufacturing. Illustrative Embodiments In one embodiment, the method further comprises a step of evaluating (investigating) the conductive material for changes, particularly before the estimating step. In this context, the term "change" may refer to a deviation of the conductive material (metal) properties from the expected properties of the conductive material. Evaluating the conductive material may provide the advantage of directly identifying irregularities or defects in the conductive material. Based on the presence of such changes, the described estimations and the described modifications of the reducing agent (composition) can be made. In other words, the evaluation of the changes can be performed before the estimating step.

[0036] In this context, an "alteration" can be considered as a physical characteristic of the component carrier or product. Nevertheless, an "alteration" can also be considered as an observable / detectable additional structure. Since the alteration is detected during the manufacturing process of product production, it can be a benchmark to assess whether a reducing agent is qualified or not. Therefore, unqualified chemicals will not be applied in product production. This can improve product quality and manufacturing efficiency (cost / labor reduction).

[0037] In one embodiment, the change includes a change in the color of the conductive material. For example, the color of a copper layer may be darker than expected. Such a color change may further be related to a thinner than expected thickness of the conductive material. Furthermore, the color of a surface can potentially affect or be indicative of surface structure or morphology, such as a change in roughness.

[0038] In one embodiment, the change comprises a change in the crystalline structure of the conductive material. In one embodiment, the change comprises a change in the material composition (e.g., dissimilar metals) of the conductive material. In one embodiment, the change may further comprise a change in at least one of the thickness, surface energy, surface roughness, surface uniformity, surface wettability, shape, and size of the conductive material structure.

[0039] In one embodiment, the changes include two or more of the changes identified above. Depending on the composition of the reducing agent, one or more of these deficiencies may occur. Nevertheless, based on the present disclosure, such deficiencies can be reliably observed and overcome accordingly (by applying benchmarks during the evaluation of the reducing agent).

[0040] In one embodiment, the reducing agent includes at least one of formaldehyde, trioxane, methanediol, and paraformaldehyde. Therefore, established, widely used (and commercially available) reducing agents can be directly applied. The inventors have discovered that such established reducing agents may contain contaminants that have a surprising effect on additive manufacturing processes, particularly electroless processes, in component carrier manufacturing. Using the described disclosure, such drawbacks can be effectively overcome by modifying the composition of the reducing agent or the reducing agent itself.

[0041] In one embodiment, estimating the composition and / or amount of specific contaminants in the reducing agent comprises particle estimation and / or characterization, which may provide the advantage of being able to investigate the composition and / or amount of contaminants in a simple and reliable manner, said particles potentially being at least partially responsible for the formation of undesirable physical features.

[0042] In one embodiment, the particles comprise inorganic particles (e.g., in the case of metal contamination). In one embodiment, the particles comprise organic particles, particularly polymers (e.g., in the case of organic contamination). In one embodiment, the particles comprise liquid droplets and / or gas bubbles, particularly water droplets. Depending on the process parameters and chemistry (e.g., with respect to the reducing agent), different particles may be generated.

[0043] In one embodiment, the particles comprise at least one of a metal, a metal salt, a glass, a ceramic, a material having at least one of the following elements: Sb, Ba, Ca, Fe, Mg, Na, Sr, Zn, Pd, Cr, Ni, Co, K, Al. Depending on the process parameters and chemistry, a wide variety of particles (contaminants) can be generated and effectively detected.

[0044] In one embodiment, the step of estimating the composition and / or amount of specific contaminants in the reducing agent comprises performing a liquid particle count analysis, which allows for reliable determination of particle characteristics using established techniques. Placing the reducing agent in a liquid and then measuring / counting the amount of particles may allow for reliable characterization of the contaminant composition / amount.

[0045] In one embodiment, the step of estimating the composition and / or amount of specific contaminants of the reducing agent, particularly with respect to metal particles, comprises elemental analysis, particularly using spectroscopic and / or analytical methods. There is a wide variety of established analytical equipment available that can be directly applied to the chemical / physical analysis of reducing agents, particularly with respect to metal particles in said reducing agents.

[0046] In a preferred embodiment, AAS (atom absorption spectroscopy) or ICP-AAS is applied: ICP (inductively coupled plasma) is a technique for preparing metals (using plasma to provide metal ions), and AAS is a method for measuring / identifying metals. Further suitable spectroscopic methods may include FAAS (flame atomic absorption spectroscopy), AES (Auger electron spectroscopy), EPR (electron paramagnetic resonance), EDS (energy dispersive spectroscopy), IR (infrared spectroscopy), UV spectroscopy, UV / VIS spectroscopy, NMR (nuclear magnetic resonance) spectroscopy, Mössbauer spectroscopy, Raman spectroscopy, XPS (X-ray photoelectron spectroscopy), XRD (X-ray diffraction), XRF (X-ray fluorescence), and XRM (X-ray microscopy). Additionally, analytical methods such as mass spectroscopy (e.g., ICP-MS) may be applied. Moreover, the present disclosure may also apply other analytical methods, such as chromatography.

[0047] Combining the listed elemental analyses may improve validity and / or precision, as each method may be more accurate for certain metals / ions.

[0048] In one embodiment, estimating the composition and / or amount of a particular contaminant in the reducing agent (particularly for organic particles) comprises analysis of organic matter, in particular at least one of chromatography, spectroscopy, in particular UV, UV-Vis, or NMR. As many contaminants may be organic, suitable analytical methods may be applied.

[0049] In one embodiment, the specific electrical characteristic of the reducing agent comprises the electrical conductivity of the reducing agent. Surprisingly, the inventors have found that electrical parameters such as electrical conductivity can provide specific information regarding the composition / amount of contaminants.

[0050] In component carrier manufacturing processes, electrical conductivity can be an indicator of the purity of the rinse water. Therefore, established processes can be directly used to measure electrical conductivity. Pure reducing agents may have low electrical conductivity, so electrical conductivity can be used as an indicator of the cleanliness of the raw chemicals. High electrical conductivity can generally be attributed to contaminants such as ions and / or metallic elements.

[0051] In one embodiment, the step of changing the reducing agent comprises changing the composition of the reducing agent or the reducing agent used in a previous additive manufacturing process, in particular an electroless process, for a subsequent additive manufacturing, in particular an electroless process, run. The described approach can be applied in stages, for example, after each manufacturing process the reducing agent and / or the conductive structure can be investigated and then adjustments made regarding the reducing agent. In other words, the described method can be used with a feedback loop to allow for (constant) adjustments.

[0052] In one embodiment, changing the reducing agent comprises providing a different reducing agent to the liquid. The reducing agent can be stored in a tank in a liquid (e.g., a solvent) and can be provided in the liquid as long as the reducing agent does not contaminate the liquid. In this context, the term "different" can refer to a different chemical composition of the reducing agent itself, or to replacing a used agent with a fresh new reducing agent (of the same composition).

[0053] In one embodiment, changing the reducing agent includes cleaning the electroless process bath used in the electroless process. The reducing agent can contaminate its environment, e.g., the liquid, bath, or tank. Therefore, for example, cleaning the bath / tank, thereby removing contaminants from the previous reducing agent, can overcome the contamination in an efficient and reliable manner.

[0054] In one embodiment, the step of modifying the reducing agent comprises purifying the reducing agent, in particular by filtering the solid and / or liquid particles / droplets of the reducing agent. Thus, reliable and well-established (chemical) purification methods can be applied to remove contaminants / contamination of the reducing agent. Such a step could only be performed due to the surprising insight of the inventors that reducing agents may be the cause of defects in the conductive material.

[0055] In one embodiment, estimating the physical characteristics of the conductive material structure includes estimating the presence of voids in said conductive material structure, which may provide the advantage of ensuring a void-free conductive layer structure inside the component carrier.

[0056] In one embodiment, estimating the physical characteristics of the conductive material structure comprises estimating protrusions, in particular nodules, extending from the overall planar extension of said conductive material structure.

[0057] Based on (clearly visible) structures such as nodules, bumps or protrusions, physical features can be inferred / determined / investigated, allowing defects to be identified quickly and reliably.

[0058] In one embodiment, the protrusions are formed on the exposed surface. In one embodiment, the protrusions are formed on a surface of the conductive material structure that is in contact with a further surface of the component carrier. The described approach can reduce or even prevent the presence of such undesired protrusions.

[0059] In one embodiment, modifying the reducing agent includes providing particles other than the total reducing agent composition, with a quantity of less than or equal to 6000 particles / mL for particles up to 0.5 μm in size. In one embodiment, modifying the reducing agent includes providing metal particles, particularly Fe, Pb, Cr, and Zn particles, with at least one of Fe, Pb, Cr, and Zn in an amount less than 1 mg / L, particularly less than 1 ppm. In one embodiment, modifying the reducing agent includes providing organic particles in an amount such that a UV-visible absorption spectrometer scan within wavelengths of 190-350 nm provides a curve deviation of less than 1 relative to the reducing agent without the organic particles. In one embodiment, modifying the reducing agent includes providing an electrical conductivity of less than 25 μS / cm. The inventors have discovered that one or more of these features can enable a reliable reducing agent composition that can significantly reduce defects in conductive material structures.

[0060] In one embodiment, the particle amount is less than or equal to 6000 particles / mL for particles up to 0.5 μm in size, in particular less than or equal to 3000 particles / mL for particles up to 0.5 μm in size, more particularly less than or equal to 1500 particles / mL for particles up to 1.0 μm in size, and even more particularly less than or equal to 1000 particles / mL for particles up to 2.0 μm in size. These measures may enable a reliable production process.

[0061] In one embodiment, analysis has shown that reducing agents in electroless baths contaminated with foreign matter can increase copper nodule defect rates by up to 20%.

[0062] In one embodiment, the metal reacts with other chemicals in the bath to produce metallic material, which exhibits higher conductivity on the electroless plating surface, which can lead to peak plating efficiency, higher plating rates in contaminated areas, and subsequent protrusion formation.

[0063] In one embodiment, the present disclosure introduces a correlation between the general chemistry of the reducing agent and the quality of the component carrier. In one embodiment, commercial suppliers of reducing agents may not recognize the importance of quality control.

[0064] In an exemplary embodiment, the method may be performed as follows (including a set threshold): i) Particle count analysis, e.g., less than or equal to 6000 particles / mL with dimensions up to 0.5 μm. LPC can help reveal whether droplets of different physical substances are present in the solution.

[0065] ii) ICP / AAS full scan metal detection, e.g. Fe / Pb / Cr / Zn<1ppm. ICP / AAS can detect contaminating elements.

[0066] iii) Use a UV-VIS (UV-visible absorption spectrometer) to scan wavelengths from 190 to 1100 nm and determine the organic contamination of the reducing agent by this absorption. For example, focus on the wavelengths from 190 to 350 nm where the absorbance deviation is <1. UV-VIS can help clarify whether there is any influence from other organic substances.

[0067] iv) Conductivity measurement of the reducing agent chemical, e.g., <25 μS / cm. Conductivity can partially detect metal contamination.

[0068] In further embodiments, the reducing agent may have pH adjusting properties. In other words, the redox potential may be affected by the pH value, which allows for specific applications. In one embodiment, the reducing agent may be acidic or basic (e.g., hydrochloric acid) to further adjust the redox potential.

[0069] In one embodiment, the component carrier is shaped as a plate. This contributes to a compact design, while the component carrier nevertheless provides a large base for mounting components thereon. Furthermore, thanks to its small thickness, bare dies in particular can be conveniently embedded in thin plates such as printed circuit boards, as examples of embedded electronic components.

[0070] In one embodiment, the component carrier is configured as one of the group consisting of a printed circuit board, a substrate (particularly an IC substrate), and an interposer.

[0071] In the context of this application, the term "printed circuit board" (PCB) may specifically refer to a plate-shaped component carrier formed by laminating several conductive layer structures with several electrically insulating layer structures, for example, by applying pressure and / or supplying thermal energy. As a preferred material for PCB technology, the conductive layer structures are made of copper, while the electrically insulating layer structures may contain resin and / or glass fibers, so-called prepreg or FR4 material. The various conductive layer structures may be connected to each other in the desired manner by forming holes through the laminate, for example, by laser drilling or mechanical drilling, and filling them partially or completely with a conductive material (especially copper), thereby forming vias or any other through-hole connections. The filled holes may connect the entire stack (through-hole connections extending through several layers or the entire stack), or they may connect at least two conductive layers and are called vias. Similarly, optical interconnections may be formed through individual layers of the stack to accommodate electro-optical circuit boards (EOCBs). Apart from one or more components that may be embedded in the printed circuit board, the printed circuit board is usually configured to accommodate one or more components on one or both of the opposing faces of the plate-shaped printed circuit board, which may be connected to each main face by soldering. The dielectric part of the PCB may be made of a resin containing reinforcing fibers (such as glass fibers).

[0072] In the context of the present application, the term "substrate" may refer, in particular, to a small component carrier. In relation to a PCB, a substrate may be a relatively small component carrier on which one or more components may be mounted and which may serve as a connection medium between one or more sub-chips and a further PCB. For example, a substrate may have substantially the same size as the components (e.g., electronic components) mounted thereon (e.g., in the case of a chip scale package (CSP)). More specifically, a substrate may be understood as a carrier for electrical connections or electrical networks and a component carrier comparable to a printed circuit board (PCB), but with a significantly higher density of horizontally and / or vertically arranged connections. Horizontal connections may be, for example, conductive tracks, while vertical connections may be, for example, drill holes. These horizontal and / or vertical connections may be arranged within the substrate and used to provide electrical, thermal, and / or mechanical connection of housed or unhoused components (e.g., bare dies), in particular IC chips, with a printed circuit board or intermediate printed circuit board. Thus, the term "substrate" also includes "IC substrate." The dielectric portion of the substrate may be composed of a resin containing reinforcing particles (such as reinforcing spheres, especially glass spheres).

[0073] In the context of the present application, the term "inorganic layer structure" may refer to a layer structure that includes inorganic materials, such as inorganic compounds. In particular, the dielectric material of the inorganic layer structure, or even the entire inorganic layer structure, may be made exclusively or at least substantially exclusively of inorganic materials. In another embodiment, the inorganic layer structure may include an inorganic dielectric material and another dielectric material. The inorganic compound may be a compound lacking a carbon-hydrogen bond or a compound that is not an organic compound. In one example, the inorganic layer structure may include glass, such as silicon-based glass, in particular soda-lime glass, and / or borosilicate glass, and / or aluminosilicate glass, and / or lithium silicate glass, and / or alkali-free glass. In another example, the inorganic layer structure may include a ceramic material, such as a ceramic material containing aluminum nitride and / or aluminum oxide and / or silicon nitride and / or boron nitride and / or tungsten. Furthermore, in another example, the inorganic layer structure may comprise a semiconductor material, such as silicon and / or germanium and / or silicon oxide and / or germanium oxide and / or silicon carbide and / or gallium nitride. In a further embodiment, the inorganic layer structure may comprise an (elemental) metal and / or a metal alloy, such as copper and / or tin and / or bronze. Furthermore, in another embodiment, the inorganic layer structure may comprise an inorganic material not listed in the above examples, such as MoS2, CuGaO2, AgAlO2, LiGaTe2, AgInSe2, CuFeS2, BeO.

[0074] The substrate or interposer may have or consist of at least a layer of glass, silicon (Si), and / or a photoimageable or dry-etchable organic material such as an epoxy-based build-up material (such as an epoxy-based build-up film), or a polymer compound such as polyimide or polybenzoxazole (which may or may not contain photo- and / or thermo-sensitive molecules).

[0075] In one embodiment, the at least one electrically insulating layer structure (and / or curable dielectric element) is made of a material selected from the group consisting of epoxy resins, cyanate ester resins, benzocyclobutene resins, bismaleimide triazine resins, polyphenylene derivatives (e.g., polyphenylene ether (PPE)), polyimide (PI), polyamide (PA), liquid crystal polymers (LCP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride, and the like. The composite material may include at least one of the group consisting of resins or polymers, such as polyvinyl chloride (PVDF) and / or combinations thereof. Reinforcing structures, such as webs, fibers, spheres, or other types of filler particles, made of glass (multilayer glass), can also be used to form composite materials. Semi-cured resins combined with reinforcing agents, such as fibers impregnated with the aforementioned resins, are called prepregs. These prepregs are often named after their properties, such as FR4 or FR5, indicating their flame retardancy. While prepregs, especially FR4, are typically preferred for rigid PCBs, other materials, particularly epoxy-based build-up materials (e.g., build-up films) or photoimageable dielectric materials, may also be used. For high-frequency applications, high-frequency materials such as polytetrafluoroethylene, liquid crystal polymers, and / or cyanate ester resins may be preferred. In addition to these polymers, low-temperature co-fired ceramics (LTCC) or other low, ultra-low, or extremely low DK materials may be applied to component carriers as electrically insulating structures.

[0076] In one embodiment, the at least one conductive layer structure comprises at least one of the group consisting of copper, aluminum, nickel, silver, gold, palladium, tungsten, carbon, platinum, (doped) silicon, and magnesium. Copper is generally preferred, but other materials or coatings thereof are also possible, especially those coated with superconducting materials or conducting polymers, such as graphene or poly(3,4-ethylenedioxythiophene) (PEDOT), respectively.

[0077] At least one component may be embedded in the component carrier and / or surface-mounted on the component carrier. Such components may be selected from the group consisting of non-conductive inlays, conductive inlays (such as metal inlays, preferably comprising copper or aluminum), heat transfer units (e.g., heat pipes), light-guiding elements (e.g., optical waveguides or light guide connections), electronic components, or combinations thereof. Inlays may be, for example, metal blocks with or without insulating material coatings (IMS inlays) and may be embedded or surface-mounted to facilitate heat dissipation. Suitable materials are defined according to their thermal conductivity, which should be at least 2 W / mK. Such materials are often based on metals, metal oxides, and / or ceramics, such as, but not limited to, copper, aluminum oxide (Al2O3), or aluminum nitride (AlN). Other geometries with increased surface area are often used to increase heat exchange capacity.Further, the component may be an active electronic component (implementing at least one pn junction), a passive electronic component such as a resistor, inductor, or capacitor, an electronic chip, a storage device (e.g., DRAM or another data memory), a filter, an integrated circuit (such as a field-programmable gate array (FPGA), programmable array logic (PAL), generic array logic (GAL), and complex programmable logic devices (CPLD)), a signal processing component, a power management component (such as a field-effect transistor (FET), metal-oxide-semiconductor field-effect transistor (MOSFET), complementary metal-oxide-semiconductor (CMOS), junction field-effect transistor (JFET), or insulated-gate field-effect transistor (FFET)). The components may be semiconductors, such as silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), gallium oxide (GaO), indium gallium arsenide (InGaAs), and / or any other suitable inorganic compound, optoelectronic interface elements, light emitting diodes, photocouplers, voltage converters (e.g., DC / DC converters or AC / DC converters), encryption components, transmitters and / or receivers, electromechanical transducers, sensors, actuators, microelectromechanical systems (MEMS), microprocessors, capacitors, resistors, inductances, batteries, switches, cameras, antennas, logic chips, and energy harvesting units. However, other components may be embedded in the component carrier.For example, magnetic elements can be used as components. Such magnetic elements can be permanent magnetic elements (ferromagnetic, antiferromagnetic, multiferroic, or ferrimagnetic elements, e.g., ferrite cores) or paramagnetic elements. However, the component can also be an IC substrate, an interposer, or a further component carrier, e.g., in a board-in-board configuration. The component can be surface-mounted on the component carrier and / or embedded therein. Furthermore, other components, in particular those that generate and emit electromagnetic radiation and / or are sensitive to electromagnetic radiation propagating from the environment, can also be used as components.

[0078] In one embodiment, the component carrier is a stacked component carrier, in such an embodiment, the component carrier is a composite of multiple layers stacked and connected together by applying pressure and / or heat.

[0079] After processing the internal layer structure of the component carrier, one or both opposing main faces of the processed layer structure can be covered symmetrically or asymmetrically (in particular by lamination) with one or more further electrically insulating and / or conductive layer structures, in other words the build-up can be continued until the desired number of layers is obtained.

[0080] After the formation of the stack of electrically insulating and conductive layer structures has been completed, it is possible to proceed with a surface treatment of the resulting layer structure or component carrier.

[0081] Specifically, an electrically insulating solder resist can be applied to one or both opposing main surfaces of the layer stack or the component carrier for surface treatment. For example, such a solder resist can be formed on the entire main surface, and the layer of solder resist can then be patterned to expose one or more conductive surface portions that are to be used to electrically couple the component carrier to peripheral electronics. Surface portions of the component carrier that remain covered with the solder resist, particularly those containing copper, can be effectively protected from oxidation or corrosion.

[0082] With regard to surface treatment, it is also possible to selectively apply a surface finish to exposed conductive surface portions of the component carrier. Such a surface finish can be a conductive cover material on exposed conductive layer structures (e.g. pads, conductive tracks, etc., particularly containing or consisting of copper) on the surface of the component carrier. If such exposed conductive layer structures are left unprotected, the exposed conductive component carrier material (especially copper) may oxidize, reducing the reliability of the component carrier.

[0083] A surface finish may then be formed, for example, as an interface between the surface-mounted component and the component carrier. The surface finish functions to protect the exposed conductive layer structure (especially the copper circuitry) and to enable a joining process with one or more components, for example, by soldering. Examples of materials suitable for the surface finish include organic solderability preservatives (OSP), electroless nickel immersion gold (ENIG), electroless nickel immersion palladium immersion gold (ENIPIG), gold (especially hard gold), chemical tin, nickel gold, nickel palladium, etc. [Brief explanation of the drawings]

[0084] The above-defined and further aspects of the invention are apparent from and will be elucidated with reference to the example embodiments described hereinafter.

[0085] [Figure 1] 1A, 1B, 1C, 1D and 1E illustrate a method for manufacturing a component carrier using an electroless process.

[0086] [Figure 2] 2A, 2B, 2C, 2D and 2E illustrate a method of manufacturing a component carrier using an electroless process.

[0087] [Figure 3] 3A and 3B show nodules as physical features in a conventional conductive structure. [Figure 4] 4A and 4B show nodules as physical features in a conventional conductive structure.

[0088] [Figure 5] 5A and 5B illustrate an additive manufacturing process according to an exemplary embodiment of the present invention.

[0089] [Figure 6] 10 illustrates estimating the composition and / or amount of specific contaminants in a reducing agent by UV absorption spectrum, according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0090] Figures 5A and 5B illustrate an additive manufacturing process according to an exemplary embodiment of the present invention. Figures 5A and 5B show the same process in principle: eless plating in a semi-additive process (equivalent processes can be used in subtractive or modified semi-additive processes). Figures 5A and 5B also show the different performance when using different reducing agents (e.g., formaldehyde).

[0091] FIG. 5A: Within the benchmark according to the present disclosure (where the composition and / or amount of specific contaminants in the reducing agent and / or specific electrical characteristics are estimated and, when a set threshold is exceeded, the composition or reducing agent is changed), the chemical reaction rate with the reducing agent in the chemical bath is normal, and the surface of the copper 120 is smooth. Copper can be deposited on the surface of an insulating material (e.g., ABF) with a target volume (e.g., over 99% copper can be deposited on the ABF surface) and with good roughness. The right side of the microscope image shows that a smooth surface is provided. Furthermore, the conductive material structure 120 is schematically shown to have the expected color.

[0092] FIG. 5B: In this case, the reducing agent is contaminated with organic substances (contaminants 110), causing an abnormal reaction in the chemical bath. As the reaction progresses, an unknown element, such as CuY, is produced, which may inhibit (slow down) the normal copper deposition rate. Y may be an organic substance containing nitrogen or sulfur, for example. Therefore, the copper surface may not be pure copper, but may contain some organic substances. The right side of the microscope image shows a rough surface. Furthermore, the conductive material structure 120 is shown to have an unexpected color (due to a color change).

[0093] On a smooth copper surface, light is reflected with very little scattering, making the surface appear uniformly shiny and bright. On a rough surface, however, light is scattered more, making the surface appear darker.

[0094] Figure 6 illustrates the steps for estimating the composition and / or amount of a specific contaminant and / or reducing agent according to an exemplary embodiment of the present invention. Generally, the range commonly used for UV-VIS to measure substances is 190-1100 nm, and there may be several wavelength bands that can produce absorption peaks, such as 190-350 nm and 400-600 nm. For example, absorption peaks for formaldehyde and methyl alcohol may occur in the 190-350 nm range, while absorption peaks for other substances may occur in the 400-600 nm range. Therefore, here, UV absorption is used to scan the 190-350 nm wavelength range to determine whether the reducing agent (composition) is affected by organic substances. For example, formaldehyde is displayed in the 190-350 nm region. If there is a particular curve shape compared to the benchmark, the sample may be contaminated with organic substances (e.g., not detected by ICP-MS or electrical conductivity). The absorbance deviation (Abs) should maintain a certain value, such as <0.5 in this example.

[0095] A shows the performance of the standard sample, while B shows the performance of a new reducing agent (measured according to the present disclosure). The difference is due to the concentration of methyl alcohol added to the reducing agent (here, formaldehyde) to stabilize its performance. Deviation between A and B cannot affect the quality of the formaldehyde as long as the deviation is less than 0.5 (regardless of whether the trend is upward or downward). (Other possible items) (Item 1) 1. A method for controlling the quality of physical features of conductive material structures formed by an additive manufacturing process, in particular an electroless process, on a component carrier during said respective component carrier manufacturing process, comprising: The additive manufacturing process includes the use of a reducing agent, the reducing agent having a specific contaminant composition and / or amount and / or specific electrical characteristics, and the method comprises: - the presence of said physical characteristics; and / or the composition and / or amount of said specific contaminants and / or specific electrical characteristics of said reducing agent; estimating, in particular determining; and - said estimated physical characteristics and / or the composition and / or amount of said specific contaminants and / or said specific electrical characteristics of said reducing agent If the set threshold is exceeded, Varying the composition of the reducing agent or the reducing agent A method comprising: (Item 2) 2. The method according to item 1, wherein the method further comprises, in particular before the estimating step, a step of evaluating the change in the conductive material. (Item 3) The said change of the conductive material, in particular copper, a change in color of the conductive material; a change in the crystalline structure of the conductive material; a change in the material composition of the conductive material; Variation in thickness of the conductive material structure including at least one of The method according to item 1 or 2. (Item 4) 4. The method according to any one of items 1 to 3, wherein the reducing agent comprises at least one of formaldehyde, trioxane, methanediol, and paraformaldehyde. (Item 5) 5. The method according to any one of items 1 to 4, wherein estimating the composition and / or amount of the specific contaminant in the reducing agent comprises particle estimation and / or evaluation. (Item 6) the particles comprise inorganic particles, and / or the particles comprise organic particles, in particular polymers, and / or The particles comprise droplets, particularly water droplets; The method according to item 5. (Item 7) 7. The method according to item 5 or 6, wherein the particles comprise at least one of a metal, a metal salt, a glass, a ceramic, a material having at least one of the following elements: Sb, Ba, Ca, Fe, Mg, Na, Sr, Zn, Pd, Cr, Ni, Co, K, Al. (Item 8) 8. The method of any one of items 1 to 7, wherein estimating the composition and / or amount of the specific contaminant in the reducing agent comprises performing a liquid particle number analysis. (Item 9) 9. The method according to any one of items 1 to 8, wherein the step of estimating the composition and / or amount of specific contaminants of the reducing agent, in particular with respect to metal particles, comprises elemental analysis, in particular using spectroscopic and / or analytical methods. (Item 10) 10. The method according to item 9, wherein the elemental analysis comprises using at least one of the following instruments: ASS, in particular ICP-AAS, ICP-MS, AES, AFS, EPR, EDS, IR, MS, NMR, Mössbauer spectroscopy, Raman spectroscopy, UV, UV / VIS, XPS, XRD, XRF, XRM. (Item 11) 11. The method according to any one of items 1 to 10, wherein the step of estimating the composition of the specific pollutant and / or the amount of the reducing agent comprises analysis of organic matter, in particular at least one of chromatography, spectroscopy, in particular UV, UV-Vis, or NMR, in particular with respect to organic particles. (Item 12) 12. The method of any one of items 1 to 11, wherein the specific electrical characteristic of the reducing agent comprises the electrical conductivity of the reducing agent. (Item 13) changing the reducing agent 13. The method according to any one of items 1 to 12, comprising changing the composition of the reducing agent or a reducing agent used in a previous additive manufacturing process, in particular an electroless process, for carrying out a subsequent additive manufacturing process, in particular an electroless process. (Item 14) changing the reducing agent 14. The method of any one of items 1 to 13, comprising providing different reducing agents to the liquid. (Item 15) changing the reducing agent 15. The method according to any one of items 1 to 14, comprising cleaning an electroless process bath used in the electroless process. (Item 16) 16. The method according to any one of items 1 to 15, wherein the step of modifying the reducing agent comprises purifying the reducing agent, in particular by filtering solid and / or liquid particles / droplets of the reducing agent. (Item 17) 17. The method of any one of items 1 to 16, wherein the estimation of a physical characteristic of the conductive material structure comprises an estimation of the presence of voids in the conductive material structure. (Item 18) - the estimation of the physical characteristics of the conductive material structure includes estimation of protrusions, in particular nodules, extending from the overall planar extension of the conductive material structure; 18. The method according to any one of items 1 to 17. (Item 19) the protrusions are formed on the exposed surface; and / or Item 19. The method according to item 18, wherein the protrusions are formed on a surface of the conductive material structure that contacts a further surface of the component carrier. (Item 20) changing the reducing agent particles other than the total composition of the reducing agent, with the particles having a size up to 0.5 μm having an amount of less than or equal to 6000 particles / mL; metal particles, in particular Fe, Pb, Cr, Zn particles, with at least one of Fe, Pb, Cr, Zn in an amount of less than 1 mg / L, in particular less than 1 ppm; organic particles in an amount such that a UV-visible absorption spectrometer scan within a wavelength of 190 to 350 nm gives a curve deviation of less than 1 relative to said reducing agent without the organic particles; Electrical conductivity less than 25μS / cm providing at least one of the features of 20. The method according to any one of items 1 to 19. (Item 21) A reducing agent composition for an additive manufacturing process, in particular an electroless process, for forming an electrically conductive material structure on a component carrier, said reducing agent composition comprising at least one reducing agent, in particular at least two reducing agents, said reducing agent composition comprising: particles other than the total composition of the reducing agent, with the particles having a size up to 0.5 μm having an amount of less than or equal to 6000 particles / mL; metal particles, in particular Fe, Pb, Cr, Zn particles, with at least one of Fe, Pb, Cr, Zn in an amount of less than 1 mg / L, in particular less than 1 ppm; organic particles in an amount such that a UV-visible absorption spectrometer scan within a wavelength of 190 to 350 nm provides a curve deviation of less than 1 for said reducing agent without organic particles; and Electrical conductivity less than 25μS / cm A reducing agent composition comprising: (Item 22) 22. The reducing agent composition according to item 21, wherein the amount of particles is less than or equal to 6000 particles / mL for particles having a size up to 0.5 μm, in particular less than or equal to 1500 particles / mL for particles having a size up to 1.0 μm, and more particularly less than or equal to 1000 particles / mL for particles having a size up to 2.0 μm.

Claims

1. 1. A method for controlling the quality of physical features of conductive material structures formed by an additive manufacturing process, in particular an electroless process, on a component carrier during the respective component carrier manufacturing process, comprising: The additive manufacturing process includes the use of a reducing agent, the reducing agent having a specific contaminant composition and / or amount and / or specific electrical characteristics, and the method comprises: the presence of said physical characteristics and / or the composition and / or amount of said specific contaminants and / or specific electrical characteristics of said reducing agent; estimating, in particular determining; and - said estimated physical characteristics and / or the composition and / or amount of said specific contaminants and / or said specific electrical characteristics of said reducing agent If the set threshold is exceeded, Varying the composition of the reducing agent or the reducing agent A method comprising:

2. The method of claim 1 , further comprising, particularly prior to the estimating step, evaluating the change in the conductive material.

3. The said change of the conductive material, in particular copper, a change in color of the conductive material; a change in the crystalline structure of the conductive material; a change in the material composition of the conductive material; Variation in thickness of the conductive material structure at least one of: The method of claim 2.

4. 10. The method of claim 1, wherein the reducing agent comprises at least one of formaldehyde, trioxane, methanediol, and paraformaldehyde.

5. The method of claim 1 , wherein estimating the composition and / or amount of the specific contaminant in the reducing agent comprises particle estimation and / or characterization.

6. the particles comprise inorganic particles, and / or the particles comprise organic particles, in particular polymers; and / or The particles comprise droplets, particularly water droplets; The method of claim 5.

7. 6. The method of claim 5, wherein the particles comprise at least one of a metal, a metal salt, a glass, a ceramic, a material having at least one of the following elements: Sb, Ba, Ca, Fe, Mg, Na, Sr, Zn, Pd, Cr, Ni, Co, K, Al.

8. The method of claim 1 , wherein estimating the composition and / or amount of the particular contaminant in the reducing agent comprises performing a liquid particle number analysis.

9. 2. The method of claim 1, wherein the step of estimating the composition and / or amount of specific contaminants of the reducing agent, in particular with respect to metal particles, comprises elemental analysis, in particular using spectroscopic and / or analytical methods.

10. 10. The method of claim 9, wherein the elemental analysis comprises using at least one of the following instruments: ASS, in particular ICP-AAS, ICP-MS, AES, AFS, EPR, EDS, IR, MS, NMR, Mössbauer spectroscopy, Raman spectroscopy, UV, UV / VIS, XPS, XRD, XRF, XRM.

11. 2. The method of claim 1, wherein the step of estimating the composition of the specific contaminant and / or the amount of the reducing agent comprises analysis of organic matter, in particular with respect to organic particles, in particular at least one of chromatography, spectroscopy, in particular UV, UV-Vis, or NMR.

12. The method of claim 1 , wherein the particular electrical characteristic of the reducing agent comprises the electrical conductivity of the reducing agent.

13. changing the reducing agent 2. The method of claim 1, comprising changing the composition of the reducing agent, or a reducing agent used in a previous additive manufacturing process, in particular an electroless process, for performing a subsequent additive manufacturing process, in particular an electroless process.

14. changing the reducing agent The method of claim 1 , comprising providing different reducing agents to the liquid.

15. changing the reducing agent The method of claim 1 including cleaning an electroless process bath used in said electroless process.

16. 2. The method of claim 1, wherein the step of modifying the reducing agent comprises purifying the reducing agent, in particular by filtering solid and / or liquid particles / droplets of the reducing agent.

17. The method of claim 1 , wherein the estimation of a physical characteristic of the conductive material structure includes estimating the presence of voids in the conductive material structure.

18. - the estimation of the physical characteristics of the conductive material structure includes estimation of protrusions, in particular nodules, extending from the overall planar extension of the conductive material structure; The method of claim 1.

19. the protrusion is formed on an exposed surface; and / or The method of claim 18 , wherein the protrusions are formed on a surface of the conductive material structure that contacts a further surface of the component carrier.

20. changing the reducing agent particles other than the total composition of said reducing agent, with the particles having a size up to 0.5 μm having an amount of less than or equal to 6000 particles / mL; metal particles, particularly Fe, Pb, Cr, Zn particles, wherein at least one of Fe, Pb, Cr, Zn is present in an amount of less than 1 mg / L, particularly less than 1 ppm; organic particles in an amount such that a UV-visible absorption spectrometer scan within wavelengths of 190 to 350 nm gives a curve deviation of less than 1 relative to said reducing agent without the organic particles; Electrical conductivity less than 25 μS / cm providing at least one of the features of 20. The method of any one of claims 1 to 19.

21. A reducing agent composition for an additive manufacturing process, in particular an electroless process, for forming an electrically conductive material structure on a component carrier, said reducing agent composition comprising at least one reducing agent, in particular at least two reducing agents, said reducing agent composition comprising: particles other than the total composition of said reducing agent, with the particles having a size up to 0.5 μm having an amount of less than or equal to 6000 particles / mL; metal particles, particularly Fe, Pb, Cr, Zn particles, wherein at least one of Fe, Pb, Cr, Zn is present in an amount of less than 1 mg / L, particularly less than 1 ppm; organic particles in an amount such that a UV-visible absorption spectrometer scan within wavelengths of 190 to 350 nm gives a curve deviation of less than 1 relative to said reducing agent without the organic particles; and Electrical conductivity less than 25 μS / cm A reducing agent composition comprising:

22. 22. The reducing agent composition of claim 21, wherein the amount of droplets is less than or equal to 6000 droplets / mL for droplets having a size up to 0.5 μm, in particular less than or equal to 1500 droplets / mL for droplets having a size up to 1.0 μm, and more particularly less than or equal to 1000 droplets / mL for droplets having a size up to 2.0 μm.

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