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Megaposit SPR 220-3.0 process recipe

SPR220-3.0 is the 3 µm-nominal grade of Rohm and Haas's MEGAPOSIT SPR 220 series, a general-purpose, broadband/g-line/i-line multiwavelength photoresist covering roughly 2-5 µm depending on spin speed, used for MEMS, plating and etch-mask applications.

https://nanyte.com/photoresists/spr220-3 · last updated 2026-07-12

At a glance
Manufacturer
Rohm and Haas Electronic Materials
Tone
Not photoimageable (underlayer)
Chemistry
DNQ-novolak
Thickness
2.3–4.6 µm
Exposure dose
310 mJ/cm² at 365 nm
Developer
MF-24A (0.24N MIF — metal-ion-free TMAH developer)
Applications
Etch mask · Electroplating / molding · MEMS structural
Etch maskSuitable for

Cross-checked — two independent extractions agree.

Coat2.3–4.6 µmSoftbake115 °C · 1.5 min · hotplateExpose310 mJ/cm² at 365 nmDevelop60 s
—01 / Coating

Spin coating

Megaposit SPR 220-3.0 is spin-coated to 2.3–4.6 µm. The curve below is redrawn from the manufacturer's published data — read your target thickness off the vertical axis and take the matching spin speed as a starting point.

Spin curve for Megaposit SPR 220-3.0: film thickness in µm against spin speed in rpm.0.002.04.01k2k3k4k5k6kSPIN SPEED (rpm)THICKNESS (µm)
Data points
Megaposit SPR 220-3.0 — film thickness (µm) by spin speed (rpm)
Seriesrpmµm
SPR220-3.015004.6
20004.0
25003.6
30003.2
35003.0
40002.8
45002.7
50002.5
55002.4
60002.3

Values are the manufacturer's starting points, not a guarantee; verify on your own tool. Characterize on-tool. Series digitized from a published figure were independently cross-checked by a second blind read; treat those values as approximate (±10 %).

re-extracted 2026-07-12, pixel-calibrated (rendered-pixel method — Figure 3 is an embedded raster image, not vector data); Figure 3 (p.2), "Spin Speed Curves on 4\"", of Rohm and Haas "MEGAPOSIT SPR220 Series Photoresists" datasheet (ME04N097, Rev. 2, Sept. 2004; UC Davis CNM2 mirror). Chart plots five curves (SPR220-7.0/circle, 4.5/square, 3.0/triangle, 1.5/diamond, 1.2/inverted-triangle), each with 10 markers from 1,500-6,000 rpm. SPR220-3.0 identified via its filled-triangle legend marker (3rd of 5 traces), cross-checked against the series-naming convention where each grade's value near 3000 rpm approximates its nominal designation (this trace reads 3.23 µm at 3000 rpm ≈ 'SPR220-3.0'). Page rendered at 10x zoom, axis calibrated from gridline pixel positions, all 10 marker centers found via per-column dark-run detection; self-consistency confirmed via a t∝1/√rpm fit (predicted-vs-read within ~1-3% across all 10 points). Supersedes the earlier 6-point eyeball read.

Redrawn from the manufacturer's published data — hover to read values between points, click to pin.

Figure 3 is measured on 4-inch substrates. Nominal film thickness may vary slightly with process, equipment, and ambient conditions, per the datasheet's own caveat under "Coat", p.2. Coat uniformity is separately reported for the SPR220-7.0 grade only (7.31 µm, standard deviation 0.036 µm across 33 points) — no uniformity figure is published for SPR220-3.0 specifically.

Adhesion
HMDS recommended — "A hexamethyldisilizane (HMDS)-based MICROPOSIT primer is recommended to promote adhesion with substrates that require such treatment. Vacuum vapor priming at 120°C for 30 seconds with concentrated HMDS is recommended." Source: "Substrate", p.2.
Rehydration
Not applicable at SPR220-3.0's nominal 3.0 µm reference thickness. The datasheet's exposure-to-PEB moisture-diffusion hold requirement applies only to "films above 4 µm" (minimum 35-minute hold) and films ">12 µm" (minimum 120-minute hold) — both thicker than this grade's 3.0 µm nominal coat, so no hold time is called for at the reference process point. (See the SPR220-7.0 entry, where this hold is required.) (Source: "Post-Exposure Bake" section, p.3)
—02 / Bake

Soft bake

Soft bake
115 °C · 1.5 min · hotplate
Notes
"The recommended softbake process for SPR220 for films up to 4.0 µm is 115°C for 90 seconds on a contact hotplate." SPR220-3.0's 3.0 µm nominal thickness falls within this \u201cup to 4.0 µm\u201d bin, so this is a direct (non-ranged) match, not a picked bin midpoint. Table 1 independently confirms the same value for the 1.1-4.0 µm thickness class: "115°C/90 sec. Contact Hotplate."

SOURCE: "Softbake" section, p.2, and Table 1 "Recommended Process Conditions" (1.1-4.0 µm column), p.1

—03 / Exposure

Exposure dose

The manufacturer publishes 310 mJ/cm² at 365 nm (SPR220 is described as "Broadband, g-Line and i-Line capable" (Advantages, p.1). Table 2 gives photospeed at both g-Line (436 nm) and i-Line (365 nm) for several dense-line/space film thicknesses; Table 1 specifies the reference exposure tool as an "ASML PAS 5500/200 i-Line (0.48 NA, 0.50σ)" stepper.). Dose scales with film thickness and depends on your optics, so treat it as a starting point and run a dose array.

Dose at 365 nm
310 mJ/cm²
Dose at 405 nm
Not published — characterize on-tool
As published
SPR220 is described as "Broadband, g-Line and i-Line capable" (Advantages, p.1). Table 2 gives photospeed at both g-Line (436 nm) and i-Line (365 nm) for several dense-line/space film thicknesses; Table 1 specifies the reference exposure tool as an "ASML PAS 5500/200 i-Line (0.48 NA, 0.50σ)" stepper.
Post-exposure bake
115 °C · 1.5 min

SOURCE: Table 2 "Photospeed and Linearity of Dense Lines/Spaces at Various Thicknesses", p.1

—04 / Development

Development

Developer
MF-24A (0.24N MIF — metal-ion-free TMAH developer)
Dilution
0.24N (MF-24A is the 0.24N-normality developer in Rohm and Haas's MF line; SPR220 is "optimized for 0.24N developers", with 0.26N (MF-26A) offered as an alternative for thicker films or high-throughput processes)
Time
60 s
Method
puddle
Rinse
Not published — characterize on-tool
Developer family
TMAH-based

SOURCE: Table 6 "Recommended Develop Conditions" (3.0 µm FT column) and Table 1, p.1 and p.3

—05 / Post-processing

Hard bake, etch & strip

Etch resistance
"Excellent wet and dry etch adhesion" (Advantages, p.1). Figure 8 (p.4) reports 100:1 etch selectivity in a Bosch DRIE process, demonstrated patterning 2.5-10 µm features to 200 µm deep and 5-20 µm features to 100 µm deep (these etch-depth examples are shown at the SPR220 series level, not attributed to a specific grade). A 1:5 HF wet-etch example (2 µm feature) is also shown on p.1.
Stripper
MICROPOSIT REMOVER 1165, two-bath process, each bath at 80°C (176°F): the first bath removes the bulk of the photoresist, the second removes residual traces. Source: "Photoresist Removal", p.4.
Storage
"Recommended storage for SPR220 is in an upright position in a dry area at 40-60°F (4-15°F). Keep away from oxidizers, acids, and bases. Keep container sealed when not in use." (Quoted verbatim, including an apparent unit inconsistency in the source: 40-60°F does not correspond to 4-15°F — the parenthetical is likely a typo for °C in the original document, but is transcribed as printed rather than silently corrected.) Source: "Storage", p.4.

Not published for this resist: Hard bake, Descum — characterize on-tool.

—06 / Applications

Where it's used

Etch maskElectroplating / moldingMEMS structural

SPR220-3.0 is the 3 µm-nominal member of the MEGAPOSIT SPR 220 line, a broadband resist usable at g-line (436 nm) or i-line (365 nm) that Rohm and Haas positions for thick-film MEMS, plating-mold, and DRIE-mask work rather than fine-pitch IC lithography. Unlike the thicker SPR220-7.0 grade, films at this 3.0 µm reference thickness stay under the datasheet's 4 µm threshold for the exposure-to-PEB rehydration hold, so processing is comparatively straightforward: softbake, PEB and (per Table 1) develop all run at essentially the textbook single-step conditions. The lineage of this resist family is worth noting for provenance purposes: Shipley Company originated the SPR line, was acquired into Rohm and Haas Electronic Materials (the entity printed on this 2004 datasheet), which was in turn acquired by Dow Chemical (2009), then spun into DuPont Electronics & Imaging, and the MEGAPOSIT/MICROPOSIT/MF brand family is now sold by Kayaku Advanced Materials — the same corporate family that owns MicroChem/KMPR and SU-8. Tone and base chemistry are not stated anywhere in this particular datasheet and are left unset rather than assumed from the product family's general reputation. Chemistry classified as dnq-novolak from the Dow MEGAPOSIT SPR220-3.0 MSDS composition table (cresol novolak resin + diazo photoactive compound) (chemistry classified 2026-07-12 from manufacturer SDS/TDS).

—07 / Sources

Sources & disclaimer

Research using this resist
  1. Koukharenko et al.. A comparative study of different thick photoresists for MEMS applications. Journal of Materials Science: Materials in Electronics (2005). doi:10.1007/s10854-005-4977-2
    Benchmarks SPR220 against SU-8 and AZ 9260 as thick-film MEMS resists.

Manufacturer datasheet values are starting points; optimal parameters depend on your substrate, equipment and environment. Product names and trademarks belong to their respective owners. NANYTE is not affiliated with the manufacturers listed. Last updated 2026-07-12.

Cite this recipe

NANYTE. "Megaposit SPR 220-3.0 process recipe." NANYTE Photoresist Library. https://nanyte.com/photoresists/spr220-3. Accessed 2026-07-12.

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