Silicon Technology

MEMS microstructures are manufactured using traditional techniques and manufacturing processes for semi-conductors, combined with specific micro-machining techniques to etch "sacrificial" layers and allowing suspended structures to be developed.

Photolithography techniques enabling volume manufacturing og millions of complex mico-chips can be used simultaneously to develop and product mechanical sensors or actuators integrated to IC. Most MEMS sytems are manufactured on silicon wafers.

MEMSCAP's design and manufacturing processes for MEMS products offer high volume production potential and are designed to guarantee high yield and reliability. Thanks to its MEMS processing and design technology expertise, the MEMSCAP team of engineers can tailor several stages in the manufacturing process as well as design features in order to obtain maximum yield.

What is remarkable about MEMS technology is that it is not a monolithic science but a combination of the complex knowledge of design, materials, processes and applications. Processes may vary greatly. As en example, techniques used for wireless communications are not suited for the development and manufacture of optical systems.

MEMSCAP is currently the only company offering the skills and resources to handle MEMS production processes, from bulk micro-machining on silicon and silicon on insulator (SOI), to surface micro-machining, including metal processes (thick copper) and micro-electronic compatible processes.

There are two main manufacturing methods:  Surface micromachining, and bulk micromachining.


Surface Micro-Machining

MEMS structures developed through surface micro-machining		MEMS structures developed through surface micro-machining

In this type of process, one of the substrate layers, called the sacrificial layer, is etched allowing a suspended layer to be developed, known as the mechanical structure. MEMSCAP has mastered this process and it is used in a host of components requiring capacitor measurement or vertical electrostatic activation. PolyMUMPs utilizes this processing technique.

Bulk Micro-Machining

MEMS structures developed through bulk micro-machining		MEMS structures developed through bulk micro-machining

In this process, the substrate itself is etched to suspend the mechanical structure. Etching can be done using chemical solutions or wet etching, or through reactive ions known as dry etching (deep RIE). This process is used for developing thermal insulation, piezo-resistance measurement (i.e. pressure sensors) or horizontal thermal, magnetic or electrostatic activation. SOIMUMPs utilize this processing technique.



Manufacturing usually applies the following processing techniques:

1. Deposition
Deposition is a key building block of MEMS processing. The ability to deposit good quality thin films of material (for subsequent local etching) usually drives the performance of the device and the manufacturing yield. MEMS deposition technology is classified in two groups:

Depositions resulting from chemical reactions: chemical vapor deposition, electrodeposition, epitaxy, and themal oxidation. These processes exploit the creation of solid materials directly from chemical reactions in gas and/or liquid compositions or in contact or not with the substrate material. The solid material is usually not the only product formed by the reaction. Byproducts can include gases, liquids and even other solids.

Depositions resulting from physical reaction: physical vapor deposition, casting. The material deposited is physically moved on to the substrate (no chemical byproduct is created).


2. Etching
In order to form a functional MEMS structure on a substrate it is necessary to etch the thin films previously deposited and/or the substrate itself. In general, there are two classes of etching processes:

Wet etching: the material is dissolved when immersed in a
chemical solution
Dry etching: the material is sputtered or dissolved using reactive
ions or a vapor phase etchant


3. Lithography
Lithography in the MEMS context is typically the transfer of a pattern to a photosensitive material by selective exposure to a radiation source such as light. When a photosensitive material is selectively exposed to radiation (e.g. by masking some of the radiation), the radiation pattern on the material is transferred to the material exposed (the properties of the exposed and unexposed regions differ).



Micro-electronic Compatible Metal Processes

MEMSCAP's patented Above-IC technology allows MEMS components to be placed on fabricated semi-conductor layers. MEMS components can then be connected to integrated circuits on the lower layers of the same chip. This manufacturing process is carried out at low temperatures so that integrated circuit functionality is not damaged and the final structure remains fully reliable.

High quality inductors using MEMSCAP's Above-IC technology		High quality inductors using MEMSCAP's Above-IC technology

Above-IC technology was developed to achieve better integration of MEMS components and integrated circuits to replace off-chip passive components. Moreover, MEMSCAP's Above-IC technology requires no changes to the micro-electronic manufacturing process or to encapsulation. This patented technology allows passive components such as specific inductors, capacitors and resistors to be developed directly above the integrated circuit, thus replacing discrete ceramic components. This integration improves reliability, performance and quality of signal transmission and reduces the size, weight and cost of telecommunications equipment. Indeed, MEMSCAP offers high-quality integrated inductors with a quality factor of up to 55 at 2 GHz. MEMSCAP considers that these values are currently the highest on the market. Standard integrated inductors offer quality factors of between 5 and 17 at 2 GHz, meaning that they are unable to meet the requirements of current wireless transmissions or those of third generation mobile telephony. Consequently, solutions presently commercially available use discrete ceramic inductors. The same applies to high-end capacitors and resistors which are currently developed using discrete components assembled on printed circuits alongside microelectronic chips. Combined or associated with integrated circuits, they form modules which can be active or passive functions. They are generally used to develop integrated wireless communications systems.



Back-end Manufacturing and Packaging

MEMSCAP controls back-end manufacturing processes, including :

Dicing processes of wafers for MEMS die singulation

Design and development of specific packages for different applications,
including packages for harsh environments

Assembly and packaging

MEMS assembly and packaging require special techniques to ensure that the potential physical stress created by these manufacturing steps are not degrading the overall MEMS die performance and configuration. The MEMS components are usually assembled in clean room environments and sealed within special packages that guarantee long term reliability and performance. MEMSCAP uses special materials to package its proprietary components, aiming at reducing manufacturing costs and package size while ensuring product performance and reliability within operation in real life environment.



QUALITY

MEMSCAP was a pioneer in the MEMS industry for quality, since the quality strategy for the North Carolina manufacturing plant was established in the late 1990s. In 2000 the facility became the 1st pure-play MEMS company to attain TL- and ISO-certification status..

Currently, MEMSCAP is certified ISO 9001:2000 and TL 9000-HW, R3.0/R3.5. Internally, we operate two Quality System metrics to define our performance:

Zero Customer incidents
100% on- time delivery

About TL- and ISO-
The TL 9000 Quality Management System (QMS) was created by QuEST Forum to meet the quality requirements of the worldwide telecommunications industry. It defines quality system requirements for the design, development, production, delivery, installation and maintenance of telecom products and services, and provides a measurement system that, when implemented, allows companies to track performance and improve results. Its telecommunications focus eliminates the need for multiple quality management standards, reduces the cost of doing business, and ultimately results in better products and services to consumers. It provides a consistent set of quality expectations needed to drive efficiency and performance across the global telecom supply chain.

The ISO 9000 family is among ISO's most widely known standards ever. ISO 9000 standards are implemented by some 760 900 organizations in 154 countries. ISO 9000 has become an international reference for quality management requirements in business-to-business dealings. The ISO 9000 family is primarily concerned with "quality management". This means what the organization needs to do to fulfill the customer's quality requirements, applicable regulatory requirements, while aiming to enhance customer satisfaction, and achieve continual improvement of its performance in pursuit of these objectives.


The Benefits of Implementation
For buyers, requiring TL 9000 certification from suppliers helps assure consistent quality across all products and services. It helps drive supply chain efficiencies and improves supplier relationships. By selecting TL 9000 certified suppliers, companies are assured that they have a QMS that has been systematically audited by an independent TL 9000 registrar. Furthermore, the advanced measurements system facilitates analysis against industry benchmarks. It provides the basis for objective product or supplier evaluations to make fully informed supply decisions. For suppliers, conformance to TL 9000 certification validates the quality of product, services and customer care that they provide. It reduces the costs of quality audits while helping create customized performance reports for current and potential customers.

TL 9000 certification, along with independent audits, allows suppliers to save time and money by complying with only one quality standard. What’s more, buyers save on the costs of on-site inspections. TL 9000 certified organizations have access to performance data reports for benchmarking that helps spur further product and service improvement and continued commitment to quality and business excellence.