INSPECTION APPARATUS AND INSPECTION METHOD FOR INSPECTING A WIRING BOARD

• US 20140375351A1
• Filed: 04/25/2014
• Published: 12/25/2014
• Est. Priority Date: 06/21/2013
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Nihon Micronics
• Original Assignee: Kabushiki Kaisha Nihon Micronics
• Inventors: Fukami, Yoshiyuki
• Granted Patent: US 9,476,934 B2
• Time in Patent Office: Days
• US Class Current: 324/763.01
• CPC Class Codes: G01R 31/2801 Testing of printed circuits, backplanes, motherboards, hybrid circuits or carriers for multichip packages [MCP] G01R31/318508 takes precedence; contactless testing G01R31/302; testing contacts or connections G01R31/66
• CPC Class Codes: G01R 31/2805 Bare printed circuit boards
• CPC Class Codes: G01R 31/2808 Holding, conveying or contacting devices, e.g. test adapters, edge connectors, extender boards probe, multiprobe, probe manipulator or probe fixture G01R1/067
• CPC Class Codes: G01R 31/2812 Checking for open circuits or shorts, e.g. solder bridges; Testing conductivity, resistivity or impedance of connections G01R31/66
• CPC Class Codes: G01R 31/2818 using test structures on, or modifications of, the card under test, made for the purpose of testing, e.g. additional components or connectors G01R31/2805 takes precedence; printed circuits having, e.g. symbols, test patterns or visualisation means H05K1/0266
• CPC Class Codes: G01R 31/2822 of microwave or radiofrequency circuits of attenuation, gain, e.g. using network analyzers G01R27/28

Abstract

An inspection apparatus for inspecting a wiring board having an opposing electrode facing an upper face of the wiring board, a capacitance meter electrically connected to the opposing electrode and the multi-layer wiring, and measuring capacitance between the opposing electrode and the multi-layer wiring, ground, a switch box that is connected to the ground wirings, the opposing electrode, and the ground, and switches to select between a first connection state, in which all the ground wirings are electrically connected to the opposing electrode, and a second connection state, in which one ground wiring is electrically connected to the ground. A control unit extracts a capacitance value by calculating difference between a first capacitance and a second capacitance, wherein capacitance in units of layers of the multi-layer wiring are measured based on the capacitance value extracted by the control unit.

Claims

1. An inspection apparatus for inspecting a wiring board that includes multi-layer wiring including electrically connecting wirings of a plurality of mutually-different layers, from an uppermost layer to a lowermost layer, and at least one ground wiring, each ground wiring being located near a wiring, other than a wiring of the uppermost layer and electrically insulated from the multi-layer wiring, the inspection apparatus comprising:

an opposing electrode that faces an upper face of the wiring board;

a capacitance meter that is electrically connected to the opposing electrode and the multi-layer wiring and measures capacitance between the opposing electrode and the multi-layer wiring;

a ground;

a switch box that is connected to the ground wirings, the opposing electrode, and the ground, and that switches to select between a first connection state, in which all of the ground wirings are electrically connected to the opposing electrode, and a second connection state, in which one ground wiring is electrically connected to the ground; and

a control unit extracting a capacitance value by calculating difference between a first capacitance that is measured in the first connection state by the capacitance meter, and a second capacitance that is measured in the second connection state by the capacitance meter, wherein capacitance in units of layers of the multi-layer wiring is measured based on the capacitance value extracted by the control unit.

2. The inspection apparatus according to claim 1, wherein the control unit is connected to the capacitance meter and stores the capacitances measured using the capacitance meter.

3. The inspection apparatus according to claim 1, wherein the control unit is connected to the switch box and controls switching of the switch box between the first connection state and the second connection state.

4. The inspection apparatus according to claim 1, wherein

the wiring board includes a plurality of the ground wirings, and one of the ground wirings is located near each wiring, other than the wiring of the uppermost layer, and is electrically insulated from the multi-layer wiring,

the second connection state includes a plurality of connection states in which one ground wiring is electrically connected to the ground, and all other ground wirings are electrically connected to the opposing electrode,

the switch box switches to select one connection state among the first connection state and the plurality of second connection states in which the ground wirings electrically connected to the ground are different from one another, and

the control unit extracts the capacitance value by calculating difference between the first capacitance and the second capacitance that is measured by the capacitance meter in one of the plurality of the second connection states.

5. The inspection apparatus according to claim 1, wherein

the multi-layer wiring of the wiring board has

a two-layer wiring structure that includes a lower layer wiring and an upper layer wiring, and

one ground wiring disposed near the lower layer wiring,

in the first connection state, one ground wiring is electrically connected to the opposing electrode,

in the second connection state, the one ground wiring is electrically connected to the ground, and

the control unit extracts the capacitance value by calculating difference between the first capacitance and the second capacitance that is measured by the capacitance meter in the second connection state.

6. A method of inspecting a wiring board that includes a multi-layer wiring including electrically connecting wirings of a plurality of mutually-different layers, from an uppermost layer to a lowermost layer, and at least one ground wiring, each ground wiring being located near a wiring other than a wiring of the uppermost layer and electrically insulated from the multi-layer wiring, the method comprising:

arranging an opposing electrode to face an upper face of the wiring board;

arranging a switch box that is connected to the ground wirings, the opposing electrode, and a ground, and switches to select between a first connection state in which all of the ground wirings are electrically connected to the opposing electrode, and a second connection state in which one ground wiring is electrically connected to ground;

measuring a first capacitance in the first connection state by switching of the wiring using the switch box;

measuring a second capacitance in the second connection state by switching of the wiring using the switch box; and

measuring capacitance in units of layers of the multi-layer wiring by extracting a capacitance value by calculating difference between the first capacitance and the second capacitance.

7. The method according to claim 6, wherein

the wiring board includes a plurality of the ground wirings, and one of the ground wirings is located near each wiring, other than the wiring of the uppermost layer and electrically insulated from the multi-layer wiring,

the second connection state includes a plurality of connection states in which one ground wiring is electrically connected to the ground, and all other ground wirings are electrically connected to the opposing electrode,

the switch box switches to select one connection state from among the first connection state and the plurality of second connection states, in which the ground wirings electrically connected to the ground are different from one another,

the second capacitance is measured for each one of the second connection states in which the ground wirings electrically connected to the ground are different from one another, by switching between wirings using the switch box, and acquiring a plurality of the second capacitances, and

the capacitance value is extracted a plurality of times using the first capacitance and each one of the second capacitances, and capacitance in units of layers of the multi-layer wiring is measured based on a plurality of the capacitance values extracted.

8. The method according to claim 6, wherein

the multi-layer wiring of the wiring board has a two-layer wiring structure including a lower layer wiring and an upper layer wiring, and one ground wiring disposed near the lower layer wiring,

in the first connection state, the one ground wiring is electrically connected to the opposing electrode, and

in the second connection state, the one ground wiring is electrically connected to the ground.