This interview explores how QPAC polymer binders are advancing semiconductor manufacturing through cleaner debinding, improved thermal management, and enhanced material reliability. The discussion also highlights emerging applications in AI data centers and high-performance computing environments, where performance, purity, and thermal efficiency are increasingly critical.
Peter Ferraro, the Director of Business Development at Empower Materials, discusses the A-Z of QPAC polymer binders in semiconductor and AlN fabrication.
Can you provide an overview of Empower Materials and where QPAC fits within its semiconductor materials portfolio?
Empower Materials is the leading manufacturer of polyalkylene carbonate polymers, producing one of the largest portfolios trading under the QPAC trade name. QPAC 40 polypropylene carbonate is the most commonly used of the portfolio. Customers around the world depend on this material for numerous binder applications, as it acts as the polymer “glue” holding particles together. As a result, it plays a central role in forming shapes and components across many industries, including semiconductor fabrication.
QPAC is typically described as a binder that facilitates key operations in ceramic and semiconductor processing. What differentiates QPAC from traditional binders usually found in semiconductor manufacturing?
QPAC polymers are exceptional binders because they deliver strong adhesive properties and outstanding mechanical properties relevant to the “green” part ahead of sintering. However, the thermal decomposition properties are the standout performers. QPAC binder burns out consistently and easily at low temperatures in many kinds of furnace environments. Compared with other conventional binders, there are extremely low levels of ash residue and contaminants left behind after the burnout step.
These properties are key in semiconductor applications because any residual contamination can severely impact the final product’s electronic or ionic conductivity. Several materials in semiconductor fabrication are also negatively affected by high temperatures associated with the debinding step. Since QPAC can be extracted at lower temperatures, this prevents any adverse reactions in the materials being bound together.
When you look specifically at semiconductor components for data centers, what are the primary performance or reliability challenges that QPAC can address?
Semiconductor use in data centers is extremely high, resulting in significant heat generation. These semiconductor components are assembled using high-purity materials, such as silicon, geranium, aluminum nitride, and silver powders, for example. Each of the materials has a function, such as controlling the flow of electrons, heat management, or performing other key functions. For electroconductivity, specific additives are introduced to the pure semiconductor materials to control the conductive or insulating aspect of the system.
The capacity to be able to adjust the rate of electrical conductivity or thermal conductivity is vitally important and can be impacted by any residual materials. Traditional binders can leave carbon residue or other contaminants that can affect electrical or thermal conductivity. The cleanliness of QPAC upon debind results in the production of a part that is virtually contaminant-free.
Aluminum nitride (AlN) is becoming increasingly prominent for use in high-power, high-frequency devices. Can you walk us through how QPAC is used in AlN fabrication and what key benefits it provides in that process?
AlN has outstanding thermal conductivity and is being used extensively in semiconductor applications. This is due to the high heat semiconductor devices generate.
AlN can dissipate heat and enhance device reliability. Parts constructed using AlN ceramic include heat sinks, thermal spreaders, and substrates for power electronic modules, as well as chip carriers and electronic housing.
The binder helps bond the ceramic and form the part by applying pressing or tape casting operations. Tapes and pressed parts made using a combination of QPAC and AlN powders demonstrate exceptional green strength and flexibility due to the polymer’s inherent properties and Tg.
Thermal management remains a critical concern in AI data centers. How does the combination of AlN substrates and QPAC-enabled processing contribute to the improved thermal performance or device efficiency at the system level?
The fabrication of parts from AlN takes advantage of QPAC’s decomposition properties. This is a high-growth area for QPAC binder, and fabricators are aware they can produce high-reliability thermal components with it.
Removing the binder from AlN parts necessitates thermal debinding in an inert environment. QPAC can be completely removed in an inert environment, such as a vacuum or nitrogen, whereas other binders leave a residue.
This advantage is key to fabricating high-quality thermal management parts for the semiconductor industry. Also, gases released during the debind step can lead to fracturing or imperfections in the part’s structure; QPAC debinds in a way that maintains a consistent, fine microporous structure. This enables better control over the thermal conductivity.
From a manufacturing perspective, how does QPAC impact yield, process cleanliness, and defect reduction in contrast to more conventional binder systems in ceramic and semiconductor workflows?
The demands of semiconductor manufacturing are extremely high, with stringent standards for purity, consistency, and dimensional precision. Choosing the right powder type is key; selecting the right binder is also extremely important. While the binder is considered an inactive component of the semiconductor part, it determines cohesiveness, interfacial stability, electrochemical, and thermal stability.
The failure rate often increases with foreign particles due to interference from binder contaminants. In QPAC, the final product contains only the intended ceramic and other additives. As a result, this preserves structural integrity with virtually no negative impact on electrical and/or thermal conductivity.
Environmental and contamination concerns are really important in semiconductor fabs. How do the decomposition profile and byproducts of QPAC have a bearing on contamination control, outgassing, and overall fab cleanliness?
QPAC has superb debinding properties and exemplary cleanliness regarding decomposition components. Atmospheric furnaces release water and CO2 as the two primary byproducts of decomposition. Whereas in inert environments, propylene carbonate vapor is also released. Yet, it is relatively simple to remove this harmless vapor from the furnace. This enables a cleaner fabrication environment overall and boosts furnace throughput as there is no carbon buildup on the equipment.
Looking forward, what new applications or device types in the AI and high-performance computing space do you think will take the most advantage from QPAC-enabled AlN and other sophisticated ceramic technologies?
QPAC-enabled AIN will provide many benefits to low-temperature sintering silver paste formulations. This includes the die attach technique for semiconductor manufacturing and silver termination of packaging pastes. During die attachment, a silicon chip is attached to the substrate or die pad of the support structure.
The integrity of the process is vital when manufacturing semiconductors to ensure the final packaging meets high-quality standards. Throughout the process, a paste made up of monometallic particles and a resin is printed directly onto the substrate in patterns that match the die’s location and shape. The die is then placed on top of the substrate and the application of heat evaporates the resin and additives. Subsequently, pressure is then applied followed by the sintering process, which may be carried out in an inert environment to prevent oxidation.
The binder is a key element in this process as it is necessary for good adhesion between the integrated circuit/die and its substrate. It must also be able to debind easily to prevent the appearance of large voids in the final connection, ensuring the semiconductor device does not fail. Moreover, there is a tendency to use fine or nano silver powder at low sintering temperatures. These finer silver particles can be sintered at temperatures around 200 °C and help improve the device’s electrical performance properties.
QPAC® 40 polypropylene carbonate rises to the most demanding of challenges when using low-sintering silver adhesive, as it can break down at temperatures as low as 150-200 °C when applied to the metal. This facilitates complete binder evaporation prior to sintering.
It should also be noted that only CO2 and water are produced during the debinding process of QPAC® 40. This enables the construction of an extremely fine pore structure in the final part. QPAC® 40 can also cleanly decompose, leaving virtually no residue, in inert and vacuum debind environments. Therefore, QPAC® is a prime choice for this application. This is what is driving the increased attention and evaluation of the low-temperature nano silver Die Attach process.
Other applications that would gain advantages from QPAC include:
- Packaging, including temporary place holders for chips on substrates
- MEMS packaging and producing channels for microfluids
- Air gaps for interconnects
For those engineers and materials scientists who may lack familiarity with QPAC, what are the most important considerations or best practices worth highlighting to successfully integrate it into pre-existing semiconductor or AlN fabrication lines?
As with any new material in a formulation, any adjustments should be based on the polymer’s functionality. Modifications will probably be most needed in the formulation to compensate for these differences. This may include changing the solvent system or adding other additives, such as dispersants and plasticizers. QPAC 40 is available in a wide range of molecular weights to provide flexibility in formulation control in parameters, such as viscosity.
Empower Materials has the relevant expertise and can offer assistance regarding formulation optimization in key semiconductor applications. We work closely with our customers, from the enquiry stage to final development, to see how QPAC can be easily incorporated into their product so that they take gains from the advantages QPAC has to offer.