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Megaposit SPR 220-7.0 process recipe

SPR220-7.0 is the 7 µm-nominal grade of Rohm and Haas's MEGAPOSIT SPR 220 series, a general-purpose, broadband/g-line/i-line multiwavelength photoresist that spin-coats from roughly 5 µm up to 30-50+ µm depending on speed, used for thick-film MEMS, plating and Bosch-etch-mask applications.

https://nanyte.com/photoresists/spr220-7 · last updated 2026-07-12

At a glance
Manufacturer
Rohm and Haas Electronic Materials
Tone
Not photoimageable (underlayer)
Chemistry
DNQ-novolak
Thickness
5.5–52 µm
Developer
MF-24A (0.24N MIF — metal-ion-free TMAH developer)
Applications
Etch mask · Electroplating / molding · MEMS structural
Etch maskSuitable for

Unverified — not yet human-checked; values transcribed from the datasheet, characterize on-tool.

Coat5.5–52 µmSoftbake115 °C · 1.5 min · hotplateDevelop2 min
—01 / Coating

Spin coating

Megaposit SPR 220-7.0 is spin-coated to 5.5–52 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 curves for Megaposit SPR 220-7.0: film thickness in µm against spin speed in rpm.0.002040602k4k6kSPIN SPEED (rpm)THICKNESS (µm)
Data points
Megaposit SPR 220-7.0 — film thickness (µm) by spin speed (rpm)
Seriesrpmµm
SPR220-7.0 (8" wafer, Figure 4)15052
25039
50022
75017
100014
150011
20009.3
25008.3
SPR220-7.0 (4" wafer, Figure 3)150010
20009.0
30007.5
40006.5
50005.9
60005.5

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 %).

SPR220-7.0 (8" wafer, Figure 4): read from figure 4 "Spin Speed Curve, SPR220-7.0 on 8\"", p.2 of Rohm and Haas "MEGAPOSIT SPR220 Series Photoresists" datasheet (ME04N097, Rev. 2, Sept. 2004; UC Davis CNM2 mirror). This figure plots a single curve for SPR220-7.0 only, so there is no grade-identification ambiguity. Read at high resolution (4x page render, cropped); all 8 published markers reported. Cross-check: the text states "a 375 RPM spin will yield a film thickness of approximately 30 µm," which interpolates consistently between this curve's 250 rpm (39.3 µm) and 500 rpm (22 µm) points, supporting the accuracy of this figure read.

SPR220-7.0 (4" wafer, Figure 3): read from figure 3 "Spin Speed Curves on 4\"", p.2 of the same datasheet. Chart plots five curves; SPR220-7.0 identified as the filled-circle series, the topmost (thickest-film) curve, consistent with legend position (listed first) and its numeric name being the highest-viscosity grade shown. Read at high resolution; 6 of 10 available markers reported (1500, 2000, 3000, 4000, 5000, 6000 rpm). Cross-check against Figure 4 at overlapping speeds: 1500 rpm reads 10.1 µm here vs. 10.5 µm on the 8-inch chart, and 2000 rpm reads 9.0 µm here vs. 9.3 µm on the 8-inch chart — the two independently-read curves agree within ~4%, supporting both readings.

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

Figure 3 (4-inch wafer) and Figure 4 (8-inch/200 mm wafer, SPR220-7.0 only) are separate empirical curves for the same grade; both are reported above rather than merged, since they come from different substrates/tool runs. Coat uniformity is reported at 7.31 µm: standard deviation 0.036 µm across 33 points (source figure/wafer size for this uniformity measurement is not stated). Nominal film thickness may vary slightly with process, equipment, and ambient conditions, per the datasheet's own caveat under "Coat", p.2.

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
"With thicker films (above 4 µm), a hold time is used between exposure and PEB to allow water (which is necessary to complete the photo-reaction) to diffuse back into the photoresist film. Thick films should use a minimum hold time of 35 minutes." SPR220-7.0's 7.0 µm nominal reference thickness is above the 4 µm threshold, so this minimum 35-minute ambient hold between exposure and PEB applies. (The document's 12 µm threshold for a 120-minute hold does not apply at the 7.0 µm nominal thickness, though it would for a thicker coat of this same grade at low rpm.) This is a genuinely easy step to omit by mistake since it sits between two other steps (expose, then PEB) rather than being a bake step itself. (Source: "Post-Exposure Bake" section, p.3)
—02 / Bake

Soft bake

Soft bake
115 °C · 1.5 min · hotplate
Notes
"For films greater than 4.0 µm, use a 30 second ramp in temperature (step-down to hotplate) to 115°C and hold for a minimum of 90 seconds." SPR220-7.0's 7.0 µm nominal thickness falls in this bin (a direct match, not a picked bin midpoint) — a 30-second temperature step-down ramp precedes the 90-second hold at 115°C. (Films >12 µm instead require a 300-second minimum hold — not applicable at the 7.0 µm nominal thickness.) Table 1 independently confirms for the 4.0-10.0 µm thickness class: "30 sec. step-down to 115°C/90 sec. Contact Hotplate."

SOURCE: "Softbake" section, p.2, and Table 1 "Recommended Process Conditions" (4.0-10.0 µm column), p.1

—03 / Exposure

Exposure dose

The manufacturer does not publish a clearing dose for Megaposit SPR 220-7.0. Determine it with a dose array on your own 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

Not published for this resist: Dose at 365 nm, Dose at 405 nm — characterize on-tool.

—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
2 min
Method
puddle
Rinse
Not published — characterize on-tool
Developer family
TMAH-based

SOURCE: Table 6 "Recommended Develop Conditions" (7.0 µm FT column), 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. The p.1 application photo ("Etched Trenches (Bosch Process), 4-10 µm Features up to 100 µm deep") shows the same class of result. (These etch-depth examples are shown at the SPR220 series level, not attributed to a specific grade.)
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

SPR220-7.0 is the thickest-nominal grade in the MEGAPOSIT SPR 220 line pictured in this datasheet, spin-coating from roughly 5 µm up to 50+ µm depending on speed and wafer size (two separately measured curves, on 4-inch and 8-inch wafers, are both captured above and agree within a few percent where they overlap). Its most easily-missed processing step is the mandatory minimum 35-minute ambient hold between exposure and PEB — water must diffuse back into the film to complete the photoreaction, and skipping this wait is a well-known way to get an incomplete or inconsistent PEB result with this resist family. The exposure-dose table only publishes i-Line numbers up to a 5.0 µm reference thickness, so there is no clean i-Line dose match at this grade's 7.0 µm nominal thickness; the nearest published numbers (g-Line 470 mJ/cm² at exactly 7.0 µm, or i-Line 380 mJ/cm² at 5.0 µm) each mismatch on either wavelength or thickness and are reported only as context, not as a scalar dose. 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 (same MEGAPOSIT SPR220 line: cresol novolak resin + diazo photoactive compound) (chemistry classified 2026-07-12 from manufacturer SDS/TDS).

—07 / Sources

Sources & disclaimer

Research using this resist
  1. Kukharenka et al.. Realization of electroplating molds with thick positive SPR 220-7 photoresist. Journal of Materials Science: Materials in Electronics (2003). doi:10.1023/A:1023923911921
    34-54 µm multi-coat SPR220-7 films used as electroplating molds.
  2. 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 220-7.0 process recipe." NANYTE Photoresist Library. https://nanyte.com/photoresists/spr220-7. Accessed 2026-07-12.

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