PROCESS FOR MAPPING FORMIC ACID DISTRIBUTION

A transfer process for bonding a solderable device to a solderable first substrate having a first oxidized surface comprises placing the solderable device proximate to the first substrate in a reducing chamber, where the first surface cannot be visually observed. We place a second substrate having a second oxidized surface in the chamber in a way to visually observe the second surface. Selecting the first substrate and the second substrate so that the reduction of the second surface correlates with the reduction of the first surface provides an indication of the degree of reduction of the first surface. Introducing a reducing agent into the chamber under reducing conditions reduces the surfaces which we track by irradiating and observing the second surface; evaluate any change in the second surface during irradiation and correlate the change with first surface reduction. When sufficiently reduced, we solder the first substrate to the device.