Printed circuit board test coupon for electrical testing during thermal exposure and method of using the same

A printed circuit board test coupon for electrical testing during thermal exposure, comprising:

• a substrate having one or more conductive layers and extending between a first side and a second side opposite the first side;
• a plurality of plated holes/vias comprising seven plated holes/vias formed within the substrate of the test coupon or extending through the entire substrate of the test coupon from a first surface on the first side of the plated hole/via to a second surface on the second side of the plated hole/via;
• a first plurality of trace patterns defining a first pattern comprising four trace patterns on the first side, each of the four trace patterns connecting to at least one of the plated holes/vias on the first side of the plated holes/vias;
• a second plurality of trace patterns defining a second pattern comprising four trace patterns on the second side, each of the four trace patterns connecting to at least one of the plated holes/vias on the second side of the plated holes/vias, the second pattern being different than the first pattern and each of the seven plated holes/vias connecting to one of the trace patterns on the first side and one of the trace patterns on the second side;
• and
• a connector pattern defined in the substrate having twenty connection points, the first and second plurality of trace patterns connected to the twenty connection points in the connector pattern,
• wherein a measurement of resistance of each of the seven plated holes/vias is provided by connecting 2 wires each of a 4-wire kelvin bridge measurement system to the first and second sides of the plated hole/via using connection points in the connector pattern for one of the first plurality of trace patterns and one of the second plurality of trace patterns that connect to said plated hole/via.

A method of testing a printed circuit board test coupon for electrical testing during thermal exposure, comprising:

• inserting the test coupon into a test machine, the test coupon comprising
• a substrate having one or more conductive layers and extending between a first side and a second side opposite the first side,
• a plurality of plated holes/vias comprising seven plated holes/vias formed within the substrate of the test coupon or extending through the entire substrate of the test coupon from a first surface on the first side of the plated hole/via to a second surface on the second side of the plated hole/via,
• a first plurality of trace patterns defining a first pattern comprising four trace patterns on the first side, each of the four trace patterns connecting to at least one of the plated holes/vias on the first side of the plated holes/vias,
• a second plurality of trace patterns defining a second pattern comprising four trace patterns on the second side, each of the four trace patterns connecting to at least one of the plated holes/vias on the second side of the plated holes/vias, the second pattern being different than the first pattern and each of the seven plated holes/vias connecting to one of the trace patterns on the first side and one of the trace patterns on the second side, and
• a connector pattern defined in the substrate having twenty connection points, the first and second plurality of trace patterns connected to the twenty connection points in the connector pattern;
• varying a temperature of a fluid toward a first temperature;
• exposing the test coupon to the fluid at the first temperature;
• varying a temperature of the fluid toward a second temperature;
• and
• exposing the test coupon to the fluid at the second temperature.

A method for testing a printed circuit board test coupon for electrical testing during thermal exposure, comprising:

• inserting the test coupon into a test machine, the test coupon comprising
• a substrate having one or more conductive layers and extending between a first side and a second side opposite the first side,
• a plurality of plated holes/vias comprising seven plated holes/vias formed within the substrate of the test coupon or extending through the entire substrate of the test coupon from a first surface on the first side of the plated hole/via to a second surface on the second side of the plated hole/via,
• a first plurality of trace patterns defining a first pattern comprising four trace patterns on the first side, each of the four trace patterns connecting to at least one of the plated holes/vias on the first side of the plated holes/vias,
• a second plurality of trace patterns defining a second pattern comprising four trace patterns on the second side, each of the four trace patterns connecting to at least one of the plated holes/vias on the second side of the plated holes/vias, the second pattern being different than the first pattern and each of the seven plated holes/vias connecting to one of the trace patterns on the first side and one of the trace patterns on the second side, and
• a connector pattern defined in the substrate having twenty connection points, the first and second plurality of trace patterns connected to the twenty connection points in the connector pattern;
• stabilizing the test coupon at a first temperature;
• measuring a first resistance of the test coupon at the first temperature;
• stabilizing the test coupon at a second temperature different than the first temperature;
• measuring a second resistance of the test coupon at the second temperature;
• and
• determining a failure of the test coupon from one or both of the first and second resistance measurements,
• wherein measuring the first and second resistance of the test coupon includes measuring a resistance of each of the seven plated holes/vias by connecting 2 wires each of a 4-wire kelvin bridge measurement system to the first and second sides of the plated hole/via using connection points in the connector pattern for one of the first plurality of trace patterns and one of the second plurality of trace patterns that connect to said plated hole/via.