Pulse-reverse copper electroplating method for void-free fill of glass-core through-vias

The glass-core advanced-packaging substrates portfolio addresses one of the most acute manufacturing bottlenecks in next-generation semiconductor packaging: the reliable metallization of through-glass vias (TGVs). As the industry migrates from organic laminates to glass-core substrates to achieve better dimensional stability, lower dielectric loss, and finer wiring pitch, the process of filling high-aspect-ratio vias with copper without voids or seams becomes both commercially critical and technically non-trivial. This asset protects a specific electroplating method — using pulse-reverse or current-ramped waveforms in combination with a tailored additive chemistry — that targets exactly this process gap. The method is applicable across aspect ratios from 3:1 to 20:1, a range that spans current production TGVs and the more aggressive geometries being developed for chiplet integration. The timing is driven by a structural substitution: glass-core substrates cannot simply borrow the acid-copper bath recipes optimized for silicon TSVs or organic PCB vias, because glass sidewall chemistry, wettability, and diffusion-barrier metallurgy differ substantially. Process teams at substrate manufacturers and OSATs are actively re-qualifying plating flows, which creates a window for licensing a purpose-designed method before de-facto standards solidify. This asset is candidly a method claim rather than a composition-of-matter patent, which means its commercial value is tied closely to adoption of the specific waveform-plus-additive combination described — but that narrower scope also makes it highly actionable for a licensee who wants a clean freedom-to-operate position around a differentiated plating flow. The strategic role of this asset within the glass-core advanced-packaging substrates portfolio is to anchor the process side of the IP stack. Composition and structure patents can define what materials go into a substrate; a method patent defines how the metallization is actually accomplished. Together they create layered IP that a competitor must clear from multiple angles. This asset is not a platform patent with unlimited reach, but within its scope — void-free fill of glass-core vias at the stated aspect ratios using the disclosed waveform and additive classes — it is a clean, independently motivated claim that fills genuine whitespace.

The core technical problem this method solves is the tendency of copper electrodeposition to close off the top of a narrow, high-aspect-ratio glass via before the interior is fully filled, producing a keyhole void or mid-seam discontinuity. In acid-copper plating, the interplay between accelerator, suppressor, and leveler additives determines whether deposition is bottom-up (superconformal, preferred for via fill) or conformal-to-pinch-off (problematic at high aspect ratio). For glass sidewalls the situation is further complicated by the inherent hydrophilicity variation of glass versus silicon, the adhesion-promotion and barrier layers typically applied before copper seed, and the need to manage ohmic heating in a resistive substrate during plating. The method disclosed here addresses these challenges through two interlocking levers. First, the waveform control: pulse-reverse plating periodically reverses current direction, briefly stripping deposited copper from the most exposed surfaces (via tops and field regions) while leaving the recessed, diffusion-limited interior regions relatively enriched. Current-ramped variants achieve a similar bottom-up bias by starting at low current density — where additive coverage on the flat field is highest — and gradually increasing to drive fill rate. Second, the additive chemistry is formulated as a Group G arm, with three distinct molecular families identified as independent working embodiments: a DMSPAPS-based arm (a sulfonate-functionalized silane or propylsulfonate compound class), a BMIM-Cl arm (the imidazolium ionic liquid 1-butyl-3-methylimidazolium chloride, used as an electrolyte modifier or leveler precursor), and a CP-DMBI/BSAED arm (an n-type organic semiconductor and a bisaryl sulfonium-derived species, used for their surface-adsorption characteristics). Each arm achieves the same functional outcome — suppression of top-down closure — through chemically distinct mechanisms, providing both design-around resistance and licensing flexibility. Computational support for the additive selection comes from cluster-expansion and adsorption-energy calculations (designated CE10 and CE17 in the simulation pipeline), which rank candidate additive molecules by their relative adsorption energy on the Cu(111) surface versus the recessed-interior Cu geometry. Molecules that preferentially adsorb at the high-curvature via mouth over the planar bottom are identified as effective levelers; molecules showing the inverse preference drive bottom-up fill. This screening methodology, while not a substitute for wet-lab validation, constrains the chemical search space substantially and provides a mechanistic rationale for the three disclosed additive arms. The simulation work is methodologically analogous to the multi-MLIP stability screening applied elsewhere in the portfolio, adapted here for an adsorption-energy ranking rather than a phonon-stability consensus. Key process targets are void-free and seam-free copper fill as confirmed by cross-sectional SEM coupon analysis — the primary open validation gate remaining. Aspect-ratio coverage from 3:1 to 20:1 is claimed, with the upper range (roughly 15:1 to 20:1) corresponding to next-generation high-density interconnect TGVs currently under development at leading substrate manufacturers. The disclosed sidewall metallurgy stack (barrier and seed layers appropriate for glass) is part of the claim boundary, which means the method is not a generic copper plating recipe but a specifically tuned flow for the glass-core context.

The addressable market for glass-core substrate process technology is estimated at $0.5 to $2 billion, reflecting the current early-production stage of glass-core substrates and the projected ramp as major chip packages adopt glass interposers and glass-core build-up substrates over the next several years. The wide range is appropriate given the technology's maturity: glass-core substrates are in risk production at Intel, Corning, AGC, and several OSAT partners, but have not yet achieved the volume that would lock in process standards. A plating method that achieves qualified, high-yield TGV fill has value both as a license to substrate manufacturers running their own plating lines and as a process-IP component for equipment suppliers and specialty chemical vendors who sell into those lines. Royalty logic for a process method patent of this type most naturally follows a per-wafer or per-panel licensing model, or alternatively a reach-through royalty on the plating chemistry consumed in the licensed process. Industry precedent from TSV copper plating (where EKC/DuPont and Enthone/Atotech chemistry licenses command both upfront and volume royalties) suggests mid-single-digit percentage royalties on plating bath chemistry sales or low-dollar-per-panel fees are realistic benchmarks. At even modest penetration of a $1 billion process-chemistry market for advanced packaging substrates, annual royalty flows in the low-to-mid tens of millions are plausible within a 5 to 7 year horizon. The more strategically valuable path, however, may be an acquisition or exclusive license by a specialty plating chemistry company seeking to differentiate its glass-core product line from acid-copper recipes it already sells for organic and silicon applications.

fill method tuned to glass-core sidewall

three independent arms; dependent arms per-arm clearance

The most direct strategic buyers for this asset are specialty electroplating chemistry companies with ambitions in advanced semiconductor packaging — Atotech/MKS Instruments, MacDermid Alpha Electronics Solutions, DuPont Electronics, and Enthone (Cookson) are the obvious names. For any of these, licensing or acquiring a method patent specifically tuned to glass-core TGV fill gives them a differentiated product story to substrate manufacturers who are currently receiving generic acid-copper recommendations. A glass-core-specific plating method with an IP basis is a meaningful sales and co-development tool for a chemistry supplier trying to lock in qualification on a new substrate platform. Exclusive licensing to a single chemistry supplier would likely represent the highest near-term value extraction, while non-exclusive licensing to multiple suppliers increases royalty pool breadth at the cost of each licensee's exclusivity premium. A second category of strategic acquirer is a glass or glass-ceramic substrate manufacturer — Corning, AGC, Nippon Electric Glass — that is vertically integrating into substrate processing and wants proprietary process IP to differentiate its glass-core offering from commodity competitors. For these buyers, the method patent becomes a component of a broader substrate-plus-process value proposition rather than a chemistry license business. Equipment suppliers to the advanced packaging plating segment (e.g., Ebara, Applied Materials, Lam Research) represent a third potential channel, as they increasingly bundle process recipes and IP with hardware to create tool-qualified process solutions for their substrate-maker customers.

The principal risk is the narrow FTO posture combined with the absence of physical fill-validation data. A licensee or acquirer faces a two-step derisking requirement: first, independent patent counsel must clear each additive arm against the deep acid-copper plating IP portfolios of established chemistry suppliers; second, wet-lab plating trials must confirm that the disclosed waveform-plus-additive combinations actually deliver void-free fill at the claimed aspect ratios on production-representative glass-core via structures. Until both steps are completed, the asset's enforceability and licensing leverage are speculative. The computational adsorption-energy screening provides directional confidence but is not a substitute for electrochemical validation in a real plating bath under production conditions. The derisking roadmap is straightforward in principle: commission independent FTO opinions on each arm in parallel with running plating coupon trials using the disclosed additive compositions and waveform parameters. The CE10/CE17 screening work provides a prioritized shortlist of candidate molecules for each arm, so trial synthesis and bath formulation can proceed with focus. If physical coupon cross-sections confirm void-free fill at aspect ratios of 10:1 and above — the range most relevant to current glass-core TGV specifications — the asset's value proposition strengthens substantially and the licensing conversation with chemistry suppliers becomes concrete rather than prospective. A buyer with in-house plating capability could complete this validation cycle within 6 to 12 months, which is well inside the window before glass-core substrate process standards consolidate.