Negative PSPI Photoresists
Inquiry
Negative photosensitive polyimide (PSPI) photoresists are specialized polymeric materials widely used in advanced semiconductor fabrication and microelectronics packaging. Unlike positive PSPI photoresists, where exposed areas become soluble, negative PSPI resists operate on the principle that UV-exposed regions undergo crosslinking, becoming insoluble in developer solutions. This unique property allows negative PSPI to form robust, high-resolution patterns, making them essential for applications requiring thick films, high aspect ratios, and superior thermal and mechanical stability.
Figure 1. Lithography process steps comparison between negative and positive photosensitive polyimide resins [1].
Typical Applications
Negative PSPI photoresists are widely applied in advanced semiconductor and microelectronics fabrication due to their excellent properties. They serve as stress buffer layers in IC packaging, relieving thermal and mechanical stress to prevent cracking or delamination, and as dielectric layers for redistribution layers (RDLs), supporting high-density interconnects during metallization and plating processes. Additionally, they act as passivation layers in power devices like insulated gate bipolar transistors (IGBTs), providing protection against moisture and contaminants, and as insulating films between metal layers, ensuring electrical isolation in multilayer circuitry. These versatile functions make negative PSPI photoresists essential materials for reliable and high-performance electronic devices.
Our Products
PR-PSPI-0004 is a high-temperature, negative-tone PSPI photoresist engineered with cyclopentane, delivering outstanding mechanical strength, thermal stability, and chemical durability. This material is ideal for use in integrated circuit stress buffer layers, advanced packaging RDLs, and passivation layers in IGBT devices.
PR-PSPI-0005 and PR-PSPI-0006 are low-temperature negative-tone PSPI photoresists also developed with cyclopentane. They are well-suited for applications such as integrated circuit stress buffer layers, RDLs in advanced packaging, and structural wall layers in filter cavity fabrication.
PR-PSPI-0007 is an intrinsic black negative-tone PSPI photoresist capable of achieving highl film thickness. Its intrinsic coloration and high-performance characteristics make it an excellent choice for pixel definition layers in Micro-LED display panels.
The following are the detailed specifications of these four products:
| Product Name | High-Temperature Negative-tone PSPI Photoresist | Low-Temperature Negative-tone PSPI Photoresist | Intrinsic Black Negative-tone PSPI Photoresist |
| Catalog Number | PR-PSPI-0004 | PR-PSPI-0005 | PR-PSPI-0006 | PR-PSPI-0007 |
| Viscosity | 3800-4000 mPa·s /25 °C | 3900-4100 mPa·s /25 °C | 3900-4100 mPa·s /25 °C | ~1000cp mPa·s /25 °C |
| Cure Temperature | 350 °C (2h) | 200 °C (2h) | 230 °C (2h) | 250 °C (1h) |
| Developer | Cyclopentanone | Cyclopentanone | Cyclopentanone | Cyclopentanone |
| Thickness after Curing | 3-30 µm | 4-11 µm | 4-11 µm | 1-5 µm |
| Resolution | 15 µm | 7 µm | 7 µm | 7 µm |
| Tensile Strength | 192 MPa | 132 MPa | 151 MPa | 123 MPa |
| Elongation | 45% | 60% | 61% | 12% |
| Modulus | 3.7 Gpa | 3.0 Gpa | 3.0 Gpa | 3.2 Gpa |
| Tg (TMA) | 276 °C | 221 °C | 239 °C | 272 °C |
| Tg (DMA) | - | 239 °C | 255 °C | 304 °C |
| Td1 | 395 °C | 283 °C | 316 °C | 287 °C |
| Td3 | 421 °C | 332 °C | 357 °C | 320 °C |
| Td5 | 469 °C | 359 °C | 380 °C | 338 °C |
| CTE (50-150 °C) | 50 (106/°C) | 50-55 (106/°C) | 45-50 (106/°C) | 63 (106/°C) |
| Stress | 25 MPa | 24 MPa | 27 MPa | - |
Dielectric Constant
(25 °C,10 GHz) | 3.2 | 3.2-3.3 | 3.1-3.2 | 3.3 |
Dissipation Factor
(25 °C,10 GHz) | 0.005 | 0.009 | 0.008 | 0.018 |
| Dielectric Strength | 250 v/µm | 305 v/µm | 347 v/µm | 341 v/µm |
| Volume Resistivity | >1.0E+16 Ω·cm | >1.0E+16 Ω·cm | >1.0E+16 Ω·cm | - |
| Surface Resistivity | >1.0E+18 Ω | >1.0E+16 Ω | >1.0E+16 Ω | - |
| Adhesion Strength | Good (Cu/Si/Al/SiN) | Good (Cu/Si/Al/SiN) | Good (Cu/Si/Al/SiN) | Good (Si/SiO2/ITO) |
| Features | Low energy
Wide process window | Low-temperature curing at 200-250 °C
Low energy, broad window | Strong light blocking
Ideal for applications requiring film thicknesses up to 5 μm |
If you are interested in our products, please contact us immediately.
Reference
- Diaham, S. Polyimide in Electronics: Applications and Processability. Polyimide for Electronic and Electrical Engineering Applications. 2021: 3.
Please kindly note that our products and services are for research use only.
