Moisture Resistant MOS Capacitors Custom Profile 30V 150 pF Capacitor Single Layer Chip For Outdoor Wireless

Custom Profile MOS Capacitor HACC151S30V101 150pF 30V Moisture Resistant Single Layer Chip for Outdoor Wireless

HACC151S30V101 Environment-Robust MOS Capacitor: Custom Geometries and Moisture-Immune 150pF

The HACC151S30V101 is a 150pF ±10% single-layer MOS capacitor rated at 30V DC, sharing the same float-zone silicon substrate, thermal SiO₂ dielectric, and TiW-Au metallization platform as the HACC series. Chip dimensions are 0.50mm * 0.50mm * 0.15mm in the standard configuration, with custom rectangular aspect ratios available up to 4:1. The device is characterized for use in environments where humidity exposure, thermal cycling, and assembly process flexibility are primary design considerations.

1. Custom Chip Geometries: Matching the Capacitor to the Substrate Layout

In hybrid microcircuits and multi-chip modules, chip component placement is often constrained by the available die-attach area between active devices, transmission lines, and substrate features. Standard square capacitor chips may not fit optimally into these spaces, forcing layout compromises. The HACC platform addresses this through configurable geometry:

• Rectangular form factors: By adjusting the photolithography mask for the top electrode and the dicing street pitch, chips can be manufactured with length-to-width ratios from 1:1 to 4:1. The capacitance value is set independently by the top electrode area within the available chip footprint. For example, a 0.30mm * 0.60mm chip (2:1 aspect ratio) can accommodate the same 150pF capacitance as the standard 0.50mm square chip, fitting into a narrow die-attach strip between parallel transmission lines.
• Bordered (margin) electrode option: In assemblies using silver-filled conductive epoxy for die attach, there is a risk that epoxy squeezed out from under the chip can creep up the sidewall and short the top electrode to the conductive substrate. The bordered variant incorporates an un-metallized SiO₂ margin (typically 25-50µm wide) around the perimeter of the top gold electrode. This ceramic border serves as a physical dam, preventing any epoxy fillet from reaching the active electrode area. The trade-off is a slight reduction in electrode area for a given chip size—typically 10-20% depending on margin width—which is compensated by a proportional increase in chip dimension to maintain the target capacitance.
• Floating backside option: Standard chips have a fully metallized gold backside for conductive die attach to ground. For applications requiring a series-connected (floating) capacitor—such as DC blocks in series with a signal path where neither terminal is grounded—chips can be supplied without backside metallization. The silicon substrate then acts as a high-resistivity dielectric support rather than an electrical terminal, and both connections are made via wire bonds to separate top-electrode pads.
• Multi-value chip sets: Within a fixed chip footprint family, capacitance can be adjusted by scaling the top electrode area. Standard values in the 0.50mm platform include 10pF, 22pF, 47pF, 100pF, 150pF, and 220pF. This allows a complete RF matching network or bypass decoupling set to be assembled using chips with identical dimensions, simplifying the assembly tooling and process recipe.

2. Moisture Immunity: Why SiO₂ Outperforms Ceramic and Polymer Dielectrics in Humid Environments

Electronic components operating in uncontrolled environments face multiple moisture-related degradation mechanisms. The HACC151S30V101 is inherently resistant to all of them through its materials system:

• Bulk water absorption—not applicable: Thermal SiO₂ is a fully dense silicate glass with no porosity, grain boundaries, or micro-voids. Water molecules (kinetic diameter ~0.27nm) cannot penetrate the amorphous SiO₂ network at any practically relevant rate. By comparison, porous ceramic dielectrics and polymer films (polypropylene, polyester, PPS) absorb measurable amounts of water, which increases the effective dielectric constant and causes capacitance to drift upward. The HACC series shows <0.1% capacitance shift after 1000 hours at 85°C/85%RH with 30V DC bias.
• Surface leakage—minimized by geometry: In humid conditions, a thin water film can condense on exposed dielectric surfaces, creating a conductive path for surface leakage current. In ceramic capacitors, the dielectric is exposed at the chip terminations. In the HACC structure, the SiO₂ dielectric is fully sandwiched between the top gold electrode and the silicon substrate, with only the thin (150µm) chip edge exposing a dielectric cross-section. The leakage current increase after 500 hours at 85°C/85%RH with bias is typically under 2* the dry baseline—remaining below 20nA at 30V.
• Electrochemical migration—no silver in the system: Ceramic capacitors with silver-palladium internal electrodes are susceptible to silver ion migration under DC bias in humid conditions. Silver ions dissolve from the anode electrode, migrate through adsorbed moisture, and deposit as metallic dendrites at the cathode, eventually causing a short circuit. The HACC metallization system—TiW, Au, and Pt—contains no silver. Gold is electrochemically noble and does not form migratory ions under any practical bias-humidity condition.
• MSL 1 rating: Per J-STD-020, the HACC151S30V101 is classified as Moisture Sensitivity Level 1, indicating unlimited floor life at ≤30°C/85%RH. No dry-pack storage, no baking before reflow, and no moisture exposure tracking is required—simplifying inventory management in production environments.

3. Environmental Qualification Test Summary

Production lots are qualified through a standardized environmental test matrix. The following results are typical for the HACC series:

4. Assembly Process Compatibility

The HACC151S30V101 supports multiple assembly process flows without requalification:

• Die attach methods: Eutectic AuSn solder (80Au/20Sn, 280-320°C peak, forming gas atmosphere) provides the lowest thermal resistance and highest mechanical strength. Silver-filled conductive epoxy (such as Epotek H20E, cure at 150°C for 1 hour) is an alternative for temperature-sensitive substrates—the Pt barrier layer in the backside metallization prevents silver-gold intermetallic formation during epoxy cure and subsequent high-temperature operation.
• Wire bonding: Thermosonic Au ball bonding (25µm wire, 120-150°C stage, 25-35gf force, 80-120mW ultrasonic) yields >6gf typical pull strength with heel-break failure mode. Ultrasonic Al wedge bonding (25µm or 33µm Al-1%Si wire, room temperature, 20-30gf force, 100-150mW ultrasonic) is available for processes that cannot tolerate heated stages. Multiple bond wires on a single pad reduce inductance proportionally to 1/N.
• Shipping formats: Standard: conductive waffle pack (2-inch, 50 or 100 cavities). Optional: gel-pak for automated vacuum pickup, tape-and-reel (8mm carrier) for high-volume SMT-compatible assembly. All formats are ESD-safe.
• Storage: Unlimited floor life at ≤30°C/85%RH (MSL 1). Recommended long-term storage: dry nitrogen cabinet or vacuum-sealed moisture barrier bag with desiccant.

Key Features

• Customizable Chip Geometry: Square (0.50mm) standard, rectangular up to 4:1 aspect ratio. Bordered electrode option for conductive epoxy assembly. Floating backside option for series-connected applications. Multiple capacitance values in the same footprint family.
• Excellent Moisture Resistance: Dense thermal SiO₂ with zero bulk water absorption. <0.1% capacitance shift after 1000hr 85°C/85%RH. No silver migration risk. MSL 1 unlimited floor life.
• Near-Zero Parasitic Inductance: Single-layer architecture with intrinsic ESL <0.05nH. SRF >5GHz for 150pF value with 0.5mm bond wire. User-tunable via bond wire geometry.
• Proven Environmental Reliability: Qualified through 1000hr HTOL, 500 cycles temperature cycling, and 500hr biased humidity. Post-stress bond pull >5gf and die shear >2.5kgf.
• Multi-Process Assembly: Compatible with eutectic AuSn and conductive Ag epoxy die attach. Supports Au ball and Al wedge wire bonding. Available in waffle pack, gel-pak, or tape-and-reel.

Electrical Specifications (T = 25°C unless noted)

Typical Applications

• Outdoor cellular base station remote radio units (RRU) where condensation and temperature cycling are normal operating conditions
• Automotive electronic control units (ECU) exposed to under-hood thermal cycling, road salt spray, and condensing humidity
• Industrial IoT sensor nodes in unconditioned factory or agricultural environments
• Marine navigation and communication electronics operating in salt-laden coastal atmospheres
• Medical wearable devices subjected to perspiration and body-worn humidity
• Multi-chip RF modules requiring a matched set of capacitance values in a uniform chip footprint for automated assembly
• Hybrid circuits where rectangular chip aspect ratios enable efficient substrate layout without wasted die-attach area

Ordering and Custom Configuration

Standard product ships as 0.50mm * 0.50mm square chips in conductive waffle packs. The following custom configurations are available on request with minimum order quantities typically starting at 1,000 pieces:

• Rectangular chips: specify length, width, and capacitance within the 10pF-220pF range
• Bordered (margin) electrode: specify margin width from 25µm to 75µm
• Floating backside (no backside metal)
• Non-standard capacitance values within the 10pF-1000pF range on the 0.50mm platform
• Gel-pak or tape-and-reel (8mm or 12mm carrier) packaging

Contact our sales team with your target specifications for a feasibility assessment, lead time estimate, and quotation.