JP2020016591A - Circuit board inspection method and circuit board inspection device - Google Patents

Abstract

To provide a circuit board inspection method and a circuit board inspection device, in which, when performing electrical inspection by heating or cooling a circuit board to be inspected up to a predetermined temperature, the time to reach a certain temperature is shortened, the constant circuit board temperature is made to be easily kept, and furthermore, a measurement system is made to be not affected in terms of temperature.SOLUTION: When a circuit board 1 to be inspected is placed on a board mounting table 10 and heated or cooled up to a predetermined temperature, the entire upper surface of the circuit board 1 to be inspected is covered with a heat insulation sheet 40 which has electrical insulation and heat/cold resistance and is flexible with low thermal conductivity.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a circuit board inspection method and a circuit board inspection apparatus, and more particularly, to a circuit board inspection technique for electrically inspecting a circuit board to be inspected by heating or cooling it to a predetermined temperature.

  For a circuit board used under high or low temperature, particularly a circuit board used for connection to an in-vehicle application or a self-heating CPU, etc., in order to secure its reliability, an assumed operating temperature (for example, −15 ° C.) 〜120 ° C.).

  Therefore, conventionally, a circuit board to be inspected is temporarily fixed to the substrate mounting table using a substrate mounting table having a heating source and / or a cooling source (preferably, a negative pressure suction type substrate mounting table), and the heating source or the cooling source is cooled. The electrical inspection is performed by heating or cooling the circuit board to be inspected to a predetermined temperature at the source.

  However, since the upper surface of the circuit board to be inspected placed on the substrate mounting table is in an open state, it takes a long time to reach a predetermined temperature, and it is difficult to maintain the temperature after reaching the predetermined temperature.

  Further, as another problem, since the entire measurement apparatus is heated or cooled by the temperature applied to the circuit board to be inspected, an error occurs in the measurement system due to the influence of temperature.

  Patent Document 1 describes that when a circuit board to be inspected is fixed to a substrate mounting table by negative pressure suction, an upper surface of the circuit board to be inspected is covered by a substrate holding film. This is for correcting the warpage and distortion generated in the substrate, and no consideration is given to the temperature.

JP 2001-235500 A

  Therefore, an object of the present invention is to shorten the time required to reach a predetermined temperature when heating or cooling a circuit board to be tested to a predetermined temperature to perform an electrical test, and to keep the substrate temperature constant after the temperature is reached. The purpose of the present invention is to make it easier to hold and not to affect the measuring system with temperature.

  The present invention includes a circuit board inspection method as a first invention and a circuit board inspection apparatus as a second invention. In order to solve the above-described problems, the first invention is a board mounting table. A circuit board inspection method for mounting a circuit board to be inspected on the circuit board and performing a predetermined electrical inspection while the circuit board to be inspected is heated or cooled to a predetermined temperature. When mounting or heating or cooling to a predetermined temperature, the entire upper surface of the circuit board to be inspected is covered with a flexible heat insulating sheet having electrical insulation, heat resistance and cold resistance, low thermal conductivity and low thermal conductivity. I have.

  According to a second aspect of the present invention, there is provided an electric circuit including a substrate mounting table on which a circuit board to be inspected is mounted, heating / cooling means for heating or cooling the circuit board to be inspected on the substrate mounting table, and an inspection probe. Inspection means, and control means for controlling the heating / cooling means and the electrical inspection means, wherein the circuit board to be inspected on the substrate mounting table is heated or cooled to a predetermined temperature by the heating / cooling means. In a circuit board inspection apparatus that performs a predetermined electrical inspection by the electrical inspection unit in a state, the entire upper surface of the circuit board to be inspected mounted on the substrate mounting table is subjected to the electrical inspection. It is characterized by being provided with a flexible heat insulating sheet having electrical insulation, heat resistance and cold resistance, low thermal conductivity, and a low thermal conductivity.

  In the first invention and the second invention, a silicone sheet is preferably employed as the heat retaining sheet. Further, an anisotropic conductive rubber sheet may be used as the heat retaining sheet.

  According to the present invention, by covering the entire upper surface of the circuit board to be inspected with a flexible heat insulating sheet having electrical insulation and low thermal conductivity, the time required to reach a predetermined temperature can be shortened, and the temperature of the substrate after reaching the predetermined temperature can be reduced. It is easy to keep the temperature constant, and it is also possible to reduce the influence of temperature on the measurement system.

FIG. 1 is a schematic diagram illustrating a configuration of a circuit board inspection device according to the present invention. FIG. 2 is a perspective view showing a main part of the present invention.

Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2, but the present invention is not limited to this.

  As shown in FIGS. 1 and 2, a circuit board inspection apparatus according to this embodiment includes a substrate mounting table 10 on which a circuit board 1 to be inspected is mounted, an inspection probe 20 as an electrical inspection means, and an entire apparatus. And control means 30 for controlling the The circuit board 1 to be inspected may be either a bare board substrate on which components are not mounted or a component mounting substrate on which components are mounted.

  The substrate mounting table 10 is formed of a flat rectangular parallelepiped with a hollow inside, and the circuit board 1 to be inspected is mounted on the upper surface 10a. In this embodiment, a large number of air suction holes 11 are formed in the upper surface 10a of the substrate mounting table 10 so as to communicate with the internal cavity.

  The substrate mounting table 10 is connected to an air pump (vacuum pump) P, and the internal air is sucked by the air pump P to be in a negative pressure, whereby the circuit board 1 to be inspected mounted on the upper surface 10a is reduced. Temporarily fixed by suction. ON / OFF of the air pump P is controlled by the control unit 30.

  Alternatively, the upper surface 10a of the substrate mounting table 10 may be covered with a permeable insulating sheet having open cells, and the circuit board 1 to be inspected may be mounted thereon and fixed by suction. Further, the circuit board 1 to be inspected may be fixed by, for example, a pressing pin (not shown) instead of the suction fixing.

  Although not shown, the substrate mounting table 10 includes a heating unit for heating the circuit board 1 to be inspected, and a cooling unit for cooling the circuit board 1 to be inspected. An electric heater may be used as the heating means, and an air-cooled type such as a chiller may be used as the cooling means. Either heating means or cooling means may be employed depending on the purpose of inspection.

  Note that it is not always necessary to provide a heating means or a cooling means on the substrate mounting table 10 itself, and heating / cooling in a high-temperature atmosphere or a low-temperature atmosphere, or heating / cooling by blowing high-temperature air or low-temperature air is also included in the present invention. included.

  A temperature sensor 12 is provided on the substrate mounting table 10. The temperature sensor 12 is preferably disposed near the upper surface (substrate mounting surface) 10 a of the substrate mounting table 10 to measure the temperature of the circuit board 1 to be inspected. The temperature signal measured by the temperature sensor 12 is sent to the control means 30.

  The inspection probe 20 includes at least two inspection probes 20a and 20b. In addition to the two inspection probes 20a and 20b, a guard inspection probe (not shown) may be further provided. There is no particular limitation on the number of test probes 20 used.

  In this embodiment, the inspection probes 20a and 20b are flying probes, each of which is held by the probe moving mechanisms 21a and 21b. The probe moving mechanisms 21a and 21b individually move the inspection probes 20a and 20b in the XYZ (left-right-front-back-vertical) directions based on the address information from the control means 30.

  As the control means 30, a microcomputer or an electronic device having a function equivalent thereto is preferably used. The control unit 30 controls the heating unit or the cooling unit based on the temperature information from the temperature sensor 12.

  In addition, the control unit 30 determines, for example, the quality of the circuit board 1 to be inspected based on the measurement signals from the inspection probes 20a and 20b, and displays the result on the display unit 31.

  In this circuit board inspection apparatus, the circuit board under test 1 is heated to a predetermined temperature by a heating means as a high temperature test, or the circuit board 1 is cooled down to a predetermined temperature by a cooling means as a low temperature test. Thereafter, for example, a continuity test between two end points is performed by the test probes 20a and 20b.

  In order to reduce the time required for the circuit board 1 to be inspected to reach a predetermined temperature during the high-temperature inspection and the low-temperature inspection, in the present invention, the heat-insulating sheet 40 is put on the circuit board 1 to be inspected.

  The heat retaining sheet 40 is preferably a sheet having electrical insulation, heat and cold resistance, low thermal conductivity, and high flexibility. Such a sheet is, for example, about 30 μm to 100 μm (particularly, about 50 μm). An extremely thin silicone sheet is best.

  The inspection step will be described. After the circuit board 1 to be inspected is mounted on the upper surface 10a of the substrate mounting table 10, the heat insulating sheet 40 is placed thereon. Then, the air pump P is activated to suck the circuit board under test 1.

  The heat retaining sheet 40 is preferably larger in area than the circuit board 1 to be inspected. According to this, the heat retaining sheet 40 can be suction-fixed together with the circuit board 1 to be inspected to the upper surface 10a of the substrate mounting table 10.

  Thereafter, the heating means or the cooling means is operated to heat or cool the circuit board 1 to be inspected, and wait until a predetermined temperature is reached. At this time, since the circuit board 1 to be inspected is covered with the heat retaining sheet 40 and it is difficult for heat to escape, it is possible to reduce the time required to reach the predetermined temperature.

  When the temperature reaches the predetermined temperature, the inspection probes 20a and 20b are lowered, the heat insulation sheet (silicone sheet) 40 is pierced and brought into contact with a measurement point (for example, a predetermined end point) to conduct a continuity test between the two end points. When the inspection is completed, the suction is released, and the circuit board 1 to be inspected is removed from the substrate mounting table 10 together with the heat retaining sheet 40, and the state is awaiting the next inspection.

  As described above, according to the present invention, since the circuit board under test 1 is covered with the heat retaining sheet 40, it is difficult for heat to escape from the circuit board 1 under test, so that the time required to reach the predetermined temperature is reduced. be able to.

  Further, after reaching the predetermined temperature, the substrate temperature can be easily maintained at a constant value, and the influence of the temperature on the measurement system can be reduced.

  In the above embodiment, the heat retaining sheet 40 is a silicone sheet. However, the heat retaining sheet 40 may be an anisotropic conductive rubber sheet. According to this, the inspection probes 20a and 20b can be electrically connected to predetermined measurement points without breaking through the heat retaining sheet 40 with the inspection probes 20a and 20b.

DESCRIPTION OF SYMBOLS 1 Inspection circuit board 10 Substrate mounting base 10a Upper surface (substrate mounting surface)
DESCRIPTION OF SYMBOLS 11 Air suction hole 12 Temperature sensor 20 (20a, 20b) Inspection probe 21a, 21b Probe moving mechanism 30 Control means 31 Display part 40 Heat insulation sheet

Claims (6)

A circuit board inspection method of mounting a circuit board to be inspected on a substrate mounting table and performing a predetermined electrical inspection in a state where the circuit board to be inspected is heated or cooled to a predetermined temperature,
When the circuit board to be inspected is placed on the board mounting table and heated or cooled to a predetermined temperature, the entire upper surface of the circuit board to be inspected is electrically insulated and has heat resistance, cold resistance and low thermal conductivity. A circuit board inspection method characterized by covering with a flexible heat insulating sheet.   The circuit board inspection method according to claim 1, wherein a silicone sheet is used as the heat retaining sheet.   The circuit board inspection method according to claim 1, wherein an anisotropic conductive rubber sheet is used as the heat retaining sheet. A substrate mounting table on which a circuit board to be inspected is mounted; heating / cooling means for heating or cooling the circuit board to be inspected on the substrate mounting table; electrical inspection means including an inspection probe; Means and a control means for controlling the electrical inspection means, wherein the circuit board to be inspected on the substrate mounting table is heated or cooled to a predetermined temperature by the heating / cooling means. In a circuit board inspection device that performs a predetermined electrical inspection by
Electrical insulation, heat and cold resistance, low thermal conductivity and flexible heat insulation covering the entire upper surface of the circuit board to be inspected mounted on the substrate mounting table at least until the electric inspection is completed. A circuit board inspection device comprising a sheet.   The circuit board inspection device according to claim 4, wherein a silicone sheet is used as the heat retaining sheet.   The circuit board inspection device according to claim 4, wherein an anisotropic conductive rubber sheet is used as the heat retaining sheet.

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