Chucks for supporting solar cell in hot spot testing

An electrical or thermal substrate testing apparatus, comprising:

• a thermal imaging camera to detect heat distribution over a top surface of a substrate;
• a chuck disposed below the thermal imaging camera, the chuck comprising a base portion and a support portion coupled to the base portion, the support portion to support the substrate above the base portion and to define a cavity between a bottom surface of the substrate and the base portion that thermally separates a portion of the bottom surface of the substrate from the base portion, and the chuck further having a bore through at least the base portion;
• a testing probe disposed below the chuck, the testing probe to make contact with the bottom surface of the substrate through the bore;
• and vacuum tunnels disposed in the chuck, the vacuum tunnels configured to hold the substrate in place during the electrical or thermal testing;
• and
• wherein the chuck is heated during the electrical or thermal testing, and wherein the cavity reduces an amount of heat transferred from the base portion of the chuck to the substrate;
• and
• wherein the amount of heat transferred is reduced to between about 0.020 W/(m*k) and 0.030 W/(m*K).