DELO-NEWS

Reliable bonding of automotive cameras

New mCD adhesives for temperature-sensitive materials

Camera-based driver assistance systems in cars are experiencing an upswing. The electronic eyes help drivers of many limousines, such as the E-class or the BMW 7 series, park, keep the car within the lane, and maintain a safe distance from other vehicles. 360° cameras will continue being in particular demand. They can reliably detect pedestrians and warn the driver in time. New technical innovations in the field of automotive cameras also create increased requirements on the individual components used for a camera. The utmost quality and reliability in terms of lens quality and pixel density are demanded. At the same time, the suppliers depend on producing as cost-effectively as possible for the automotive market as competition is tough. This is where high-tech adhesives come into play. Even if it is often only a very tiny drop, adhesives are already used in millions of cameras. They ensure that certain components of the automotive camera are reliably bonded and therefore working properly. Adhesives are required for a great variety of components. They bond housings, sensors to printed circuit boards, or lenses.

Adhesives for sensitive materials

The materials used in automotive cameras are mostly sensitive to elevated temperatures. “The previously used adhesives often required elevated temperatures to cure reliably”, explains Marc Schwarz, Process Manager at DELO Industrial Adhesives. “But high temperatures may be a problem for temperature-sensitive components. With our newly developed mCD adhesives, we close an important gap.” The advantage of these adhesives is that they are low-temperature curing at +80 °C. Therefore, they lend themselves for temperature-sensitive materials and are ideal for fast processes with high output as they cure within a very short period of time. The adhesive range developed in DELO’s labs meets numerous requirements. They give high adhesion to disparate substrate materials, such plastics as PC, PA, PBT, ABS/PC, LCP, PPS, and also glass, ceramic and FR4. This method is used to bond, for example, compact camera modules such as image sensor chips to PCBs, or housings.

 

Use of DELO-DUALBOND for active alignment

In particular, the low-temperature-curing adhesives like the dual-curing DELO-DUALBOND are used in the “active alignment” process. The issue here is to balance tolerances of optical assemblies and sensors in production with the help of multi-axis active alignment. Optical components like mirrors, lenses, or prisms are aligned on the substrate during fixing by means of the adhesive. The adhesive must remain liquid during alignment. As soon as the component has obtained the correct position for optimal image quality, the adhesive is quickly lightcured within a few seconds. Afterwards, the adhesives have achieved sufficient initial strength to keep the components fixed in the desired position for subsequent final curing by heat at only 80 °C. This ensures that adhesive in shadowed areas is also reliably cured. In contrast, purely UV-curing products can often not be completely cured. In addition, uncured adhesive would lead to reduced reliability and increased waste rates in the production process. In particular, as long as the adhesive is liquid this results in outgassing. Fast preliminary fixing with UV lights eliminates long curing times. That means that the customer benefits from short cycle times, high output, and low-temperature curing when using temperature-sensitive components. It is important that the adhesive shows only low shrinkage so that the correct position of the component is maintained. The new DELO-DUALBOND adhesives are characterized by low water absorption and low shrinkage. “At the same time, no decomposition products may condensate on the optical elements. Furthermore, no corrosion may occur on surrounding electronic components”, adds Marc Schwarz.

Comprehensive testing

The adhesives were thoroughly tested. The tests performed include durability tests and aging tests, like the special 85 °C / 85 % r. h. test over a period of 1000 h, as well as various shrinkage tests. The results prove that the adhesive completely meets all requirements. DELO has developed a specifically tailored LED lamp range that is ideal to cure the mCD adhesives. In the field of compact camera modules, DELO Industrial Adhesives works together with machine manufacturers all over the world in order to jointly develop trendsetting solutions.

 

Sabine Herold elected into the BDI Board

The BDI members elected Sabine Herold into the Board of the Federation of German Industries. Thus, DELO’s Managing Partner is part of this executive committee for the first time since January 1st, 2011. The BDI Board is responsible for all substantive tasks within the Federation. Hans-Peter Keitel was re-elected BDI President for another two-year term. The BDI acts on behalf of 36 trade associations throughout Germany and represents the interests of more than 100,000 businesses with about seven million employees. Amongst others, Maria-Elisabeth Schaeffler, Managing Partner of Schaeffler KG, Dieter Zetsche, Chairman of Daimler AG, and Rüdiger Grube, Chairman of Deutsche Bahn AG, were also elected into the Board. Sabine Herold has already been a member of the BDI’s committee of medium-sized businesses since 2004 and is politically committed to the concerns of medium-sized businesses through memberships in disparate associations.

DELO among TOP 100 fastest-growing companies

DELO Industrial Adhesives is among the TOP 100 fastest-growing and most profitable medium-sized businesses in Germany. This is the result of a study of the German daily “Die Welt” and the Munich Strategy Group management consultancy. In the “TOP 100 – Ranking of Medium-Sized Businesses 2010” study, the sales and yield rates of medium-sized companies from 2005 to 2009 were analyzed. Despite the years of crisis, DELO could record average sales growth of 15 percent during that time. The relevant criteria also included extraordinary management performance, customer proximity and excellent products in the specific industry. More than 1000 medium-sized companies from disparate industries and regions with sales revenues between EUR 10 and 300 million were analyzed.

New DELO Managers in the USA and China

DELO continues expanding into innovative markets such as photovoltaics, RFID and smart card. Since 2010 the company has been strengthening its presence in the USA.
Dr. John Herold, who worked in the DELO headquarter before, will be the Executive Vice President of the US team in Boston.
Torsten Uske, former Chief Representative of DELO’s Shanghai office, will be responsible for customer support at the US West Coast.
Edward Newsom will be the new Chief Representative of DELO’s Shanghai Representative Office in China. Before, he worked as the UK Regional Sales Manager for about three years.

Application example: COB encapsulation on PCB by RAFI Eltec

DELO has recently developed the DELO-MONOPOX GE785 and DELO-MONOPOX GE725 anhydride adhesives. RAFI Eltec GmbH, Überlingen, Germany uses these adhesives as Dam&Fill. The company employs 250 people and produces electronic assemblies and systems for diverse lines of business as a manufacturing service provider. RAFI Eltec combines standard assembly technologies with special techniques such as chip-on-board and flip-chip.

For the present assembly, the solder deposits are attached to the bottom in the form of BGA ballings, followed by one-side SMD assembly. The SMD assemblies produced are subsequently Dam&Fill-encapsulated. In this method, two beads of DELO-MONOPOX GE785 are circumferentially dispensed as “Dam” on top of each other, which are subsequently “Fill”-ed with DELO-MONOPOX GE725. For this purpose, a screw dispensing valve is used in order to ensure that the components are evenly dispensed. Afterwards, the components are lasermarked on the encapsulation that has been cured in an air convection oven at 150 °C for 20 min. Adhesive processing is reliable and planar, large-area encapsulation geometries are possible. In addition, the adhesive fulfills all requirements on solder resistance. The advantage is that the dispensing profile can easily be adjusted to the specific package geometry, enabling high flexibility in production. It also gives a very homogeneous processing behavior, protects the component resp. the sensitive electronic parts from environmental influences, and performs excellently in reliability qualification tests. The material’s properties minimize the stress in the package. Thanks to the planar encapsulation, the component can be assembled just like a BGA module.

Microelectronic packages with high reliability

The application example demonstrates that the encapsulation compounds present ideal properties for being used in highreliability applications. The adhesives are based on epoxy resins that contain organic anhydrides as the hardener component. They protect the sensitive electronic packaging parts in a flexible, efficient and reliable way from aggressive environmental influences, such as oil, fuel, vibrations or elevated temperatures. They offer a range of properties which has not previously been possible with encapsulation compounds in this combination. Thanks to their special flow behavior they can be evenly dispensed. On top of this, they cure significantly faster than comparable products. This combination enables fast and stable production processes. As a consequence, the efficiency of electronic production can be ramped up. What is more, they are highly resistant to many media such as oil or fuel, and resistant to elevated temperatures.

Conclusion

Reliable encapsulation of microelectronics that must function under extreme conditions presents great challenges for the developers. The development of the new anhydride adhesives is a major step towards more reliable operation of sensors and COBs over their entire service life. In addition, production processes can be designed in a more flexible and efficient way by using the new materials. This helps manufacturers to cut down production costs and boost output.

 

Interested in our specialist article on anhydride adhesives? Order it now: marcom@delo.de

Black Dam&Fill encapsulants

Ideal for the smart card industry

DELO has recently developed new Dam&Fill chip encapsulation compounds. These heat-curing adhesives are optically intransparent, give very high mechanical protection, and can easily be processed on already existing encapsulation systems. They are used for encapsulating smart cards. The requirements prevailing in the smart card industry are enormous. The reason is that the module’s functioning must be safeguarded from production to mail dispatch to its use by the end user as a chip card (ID card, bank card, health insurance card, pay-TV card, phone card) or as a SIM card in the cell phone. The chip and the contact must be reliably mechanically protected from pressure, bending and torsion. It is also necessary to protect the sensitive silicon chips and gold wires from physical influences and environmental conditions, such as humidity, cold or heat.

Innovative encapsulation technology

The new Dam&Fill adhesives give major advantages for these special requirements, especially in the security field. Their new chemical composition makes possible very fast curing. In addition, a very high degree of mechanical protection can be reached. What is brand-new is the possibility to encapsulate the chips in such a way that opacity is given without molding them in an expensive process. This is especially important for light-sensitive chips, or if the chips are to be hidden for security reasons. Unlike UV-curing encapsulants, the new adhesives can achieve complete intransparency in the range of UV light and visible light and in the near IR range. It is possible to process and cure the new products on existing chip encapsulation systems. Therefore, it is not necessary to invest in new special equipment. The only precondition is that the systems are retrofitted with modern heating bars. Furthermore, the minimum curing temperature of 110 °C and curing times of a few minutes open up further application opportunities.

 

Interested in learning more about our black chip encapsulation compounds? Order data sheets and product information: marcom@delo.de

Adhesives and screws complement each other

The ONSERT® procedure is ideal for light-weight construction

Fast and process-reliable bonding of connection elements was the focus in the joint project of DELO and Böllhoff. They developed a new joining method that combines the two connection technologies of bonding and screwing. It is increasingly being used, particularly in light-weight construction, to connect new materials such as CFRP or thin sheet metal. In the interview, Michael Stumpf, Product Manager at Böllhoff, and Christian Walther, Sales Director at DELO, answered our questions on ONSERT®.