Sony Corp. has disclosed a defect in part of its CCD image sensors and indicated that products featuring these CCDs might "be unable to display images on finders and LCD screens, record images, render sufficient images and so on." The cause of the defect is bonding wire used to joint a CCD chip and a lead frame, which comes off due to aging. Sony offers free repair for products presenting the abovementioned malfunctions.
Targeted products for this free repair extend to a broad range, because the failure was found in a CCD image sensor, a component that is widely used. Items expected to need the repair are PDAs, digital still cameras, digital video cameras and professional video cameras. Of these items, those sold inside Japan reach more than 40 models, while those marketed outside Japan extend to more than 60 models.
What caused the defect was the company's CCD image sensor manufacturing line. To boost the line's productivity, Sony changed settings of a wire bonding system in the course of manufacturing process enhancement. As a result, the joint between wire and electrodes became weaker than before then.
An adhesive, used to bond the CCD sensor's glass and package, further degraded the wire joint surface. In most CCD image sensors, visible light transmissive glass is overlaid and bonded onto a hollow plastic packing a CCD. An iodine compound used to bond this glass and the package seems to have vaporized from inside the package, reached the wire joint and decayed the alloy on the joint surface (Sony PR).
To prevent similar defects, Sony decided to remove the iodine compound adhesive from the manufacturing process of CCD image sensors. In addition, the company has already introduced a test system to measure boding strength in around March 2004. Through these two measures, Sony insists it can prevent reoccurrence of such a failure.