Considerations for using low dielectric constant material as re-passivation layer on 300mm wafer bump process and manufacturing benefits of flip chip package

2014

ECS Trans.

Photodefinable polybenzoxazole (PBO) has been integrated as intermetal dielectric in GaAs hetero-junction bipolar transistor (HBT) technology. Process module optimization and integration studies were performed and the results and process flow were compared to those of dry-etch polyimide. The photodefinable PBO is shown to allow the intermetal dielectric process flow to be simplified and the number of processes and equipment to be reduced. Results show that PBO has more planarity than polyimide, when coated on GaAs HBT wafers, which typically have significant topography. The photolithography coat, expose, and develop processes were optimized to obtain the desired dielectric thickness and the required via dimension and sidewall profile, in addition the removal of the PBO from the die street. The PBO thermal curing process was performed at 300 o C, while plasma ashing was performed to remove any PBO residue from the bottom of the vias. These results show that the photodefinable PBO film is compatible with, is suitable for, and can be integrated as intermetal dielectric in GaAs HBT technology.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Integration of Photodefinable Polybenzoxazole as Intermetal Dielectric for GaAs HBT Technology

2014

ECS Trans.

“…The most widely used are spin-on and plasma-enhanced chemical vapor deposition (PECVD) dielectrics. The spin-on dielectrics include both organic and inorganic films, such as benzocyclobutene (BCB), spin-on glass (SOG), polyimide, polybenzoxazole (PBO), and many others (1,6,7,(13)(14)(15). The most commonly used PECVD films include undoped and doped silicon dioxide (SiO 2 ), silicon oxynitride (SiON), and silicon nitride (Si 3 N 4 ) (11,12,(16)(17)(18)(19)(20)(21)(22).…”

Section: Introductionmentioning

confidence: 99%

Comparison of Interlevel Dielectric Processes Using PECVD Silicon Nitride, Polyimide, and Polybenzoxazole for GaAs HBT Technology

2009

ECS Trans.

In this study, we have evaluated several interlevel dielectric materials for GaAs hetero-junction bipolar transistor (HBT) technology. This technology requires the material to have good gapfill and planarizing characteristics, as the various device and interconnect structures can have significant topography. Additionally, the process typically can only have a maximum temperature of <300oC, as device degradation can occur at higher temperatures. The dielectric materials evaluated are PECVD silicon nitride (Si3N4), polyimide, and photodefinable polybenzoxazole (PBO). The PECVD Si3N4 is mostly conformal when deposited. However, it has a high dielectric constant, cannot be used as gapfill material, and does not planarize the underlying topography, which makes multilevel metallization challenging. Polyimide and PBO, both of which need to be thermally cured, have lower dielectric constant than PECVD Si3N4. However, the polyimide has to be dry-etched, unlike the photosensitive PBO. Furthermore, the PBO has better gapfill and planarization capabilities than polyimide.

“…The spin-on dielectrics include both organic and inorganic films, such as benzocyclobutene ͑BCB͒, spin-on glass, polyimide, polybenzoxazole ͑PBO͒, and many others. 1,6,7,[13][14][15] The most commonly used PECVD films include undoped and doped silicon dioxide ͑SiO 2 ͒, silicon oxynitride ͑SiON͒, and silicon nitride ͑Si 3 N 4 ͒. 11,12,[16][17][18][19][20][21][22][23] In GaAs technology, there are many factors that need to be taken into consideration when selecting an interlevel dielectric material, and depending on the material selected, the process flow is different.…”

mentioning

confidence: 99%

Interlevel Dielectric Processes Using PECVD Silicon Nitride, Polyimide, and Polybenzoxazole for GaAs HBT Technology

2009

J. Electrochem. Soc.

Multiple factors need to be considered when selecting an interlevel dielectric material for GaAs semiconductor device fabrication including what the electrical, mechanical, chemical, thermal, and cost requirements are and whether the material and the process are compatible with GaAs processing. In this study, we evaluated several interlevel dielectric materials for GaAs heterojunction bipolar transistor ͑HBT͒ technology. This technology requires the material to have good gapfill and planarizing characteristics, as the various device and interconnect structures can have significant topography. Additionally, the process typically can only have a maximum temperature of Ͻ300°C, as device degradation can occur at higher temperatures. The dielectric materials evaluated are plasma-enhanced chemical vapor deposition ͑PECVD͒, silicon nitride ͑Si 3 N 4 ͒, polyimide, and photodefinable polybenzoxazole ͑PBO͒. The PECVD Si 3 N 4 is mostly conformal when deposited. However, it has a high dielectric constant, cannot be used as gapfill material, and does not planarize the underlying topography, which makes multilevel metallization challenging. Polyimide and PBO, both of which need to be thermally cured, have a lower dielectric constant than PECVD Si 3 N 4 . However, the polyimide in this study has to be dry-etched, unlike the photosensitive PBO. Furthermore, the PBO has better gapfill and planarization capabilities than polyimide.Dielectrics are widely used for various applications in semiconductor device fabrication in the processing of both silicon and compound semiconductors, such as GaAs. They include applications, such as surface passivation, premetal dielectric, capacitor dielectric, interlevel dielectric, antireflective coating, final passivation, redistribution layer, and as a stress buffer layer and an encapsulant in packaging. [1][2][3][4][5][6][7][8][9][10][11][12] There are several types of dielectrics that are typically used for interlevel dielectrics. The most widely used are spin-on and plasma-enhanced chemical vapor deposition ͑PECVD͒ dielectrics. The spin-on dielectrics include both organic and inorganic films, such as benzocyclobutene ͑BCB͒, spin-on glass, polyimide, polybenzoxazole ͑PBO͒, and many others. 1,6,7,13-15 The most commonly used PECVD films include undoped and doped silicon dioxide ͑SiO 2 ͒, silicon oxynitride ͑SiON͒, and silicon nitride ͑Si 3 N 4 ͒. 11,12,[16][17][18][19][20][21][22][23] In GaAs technology, there are many factors that need to be taken into consideration when selecting an interlevel dielectric material, and depending on the material selected, the process flow is different. One of the most important considerations is the temperature and thermal budget constraint of the technology for which the interlevel material is to be used. For instance, while the maximum processing temperature for the backend-of-line for Si technology typically is 400°C, the maximum temperature for most GaAs technologies is 300°C or less. At temperatures higher than 300°C, significant GaAs device degradation occ...