Staying on Top
Electronic Adhesive for Delicate Structures
The electronic adhesive DELO MONOPOX GE7985 features very thin and high walls at the same time. It has been developed for automotive and industrial applications requiring miniaturized designs in combination with high reliability.
Given the increasing miniaturization in electronics, there is only limited space for adhesive beads. The new product has smaller fillers than previous dam products, allowing it to be applied with needles of a minimum diameter of 250 µm, which is important. Thanks to an exceptionally high viscosity of 160,000 mPas, the adhesive additionally provides high flow resistance and an aspect ratio of 2.5. This means that the height of an adhesive bead can be more than twice its width, without the bead collapsing.
These properties make the easy-to-handle adhesive perfectly suited for finest structures such as high separating walls between sensors, for example, which require little width. Stacking of bead layers, known as “dam stacking”, is possible without curing in between. In addition to these design options, DELO MONOPOX GE7985 ensures high reliability. Its outstanding properties include an extended service temperature range up to +200 °C, low water absorption, and very good resistance to acids, oils, and other aggressive media.
No Warpage in the Package
In addition, the black, one-component product has a coefficient of thermal expansion (CTE) of 24 ppm / K, which, combined with the high glass transition temperature of +180 °C, keeps warping at a very low level over a broad temperature range, thus minimizing stress to the package.
Finally, the new DELOMONOPOX GE7985 features good strength on the FR4 PCB material, reaching a compression shear strength of 49 MPa. This value changes very little even after 500 hours of storing at +200 °C, it is still at 43 MPa.
The adhesive cures under heat with variable conditions in terms of time and temperature, for example, 20 minutes at +150 °C or 90 minutes at +125 °C. Thanks to the adhesive’s flow resistance, the aspect ratio does not change during this process, so the height of the adhesive bead remains the same after heat curing.