JPS62127660A - Pattern inspecting device - Google Patents

Abstract

PURPOSE:To inspect the state of a print pat6tern speedily by heating the print pattern by a heating means, finding temperature distribution information on the pattern, and collating it with normal temperature distribution information. CONSTITUTION:Respective styli 3 for heat conduction are heated by a heater controller 4 to specific temperature and heat is conducted to respective print patterns p<1>-p<6>, which are heated. A scanning thermometer 7 scans a printed wiring board 1 entirely and an electric signal corresponding to the temperature distribution is converted into a digital signal, which is stored in an image memory 8. A main control part 10 reads the temperature distribution information out of the image memory 8 and collates it with the normal temperature information stored in a normal temperature map 9. Consequently, cracking, chipping, whiskers, contacting, wire breaking, etc., are detected securely only in one inspection process as to the respective print patterns p<1>-p<6>.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a novel pattern inspection device for printed wiring boards.

[Technical background of the invention]

Conventionally, printed patterns on printed wiring boards are inspected by performing a two-step inspection process to detect wire breaks and the like. That is, in the first inspection process, the printed wiring board is
The print pattern is imaged by placing it within the field of view of a V camera (industrial television camera). Then, the image data of the obtained print pattern is compared with the reference image data of the pudding 1 pattern stored in advance, and based on the results, defects such as holes, scratches, hairs, shorts (contacts), etc. in the print pattern are detected. When this inspection process is completed, the second inspection process begins, in which at least two probes are brought into contact with predetermined positions on the printed pattern, an electrical signal is supplied between the two probes, and the electrical resistance value at this time is extracted. Disconnections in the printed pattern are directly detected.

[Problems with background technology]

As described above, the print pattern inspection is completed through a two-step inspection process, which takes time. Also,
In the case of disconnection detection, if the resistance value is the same, even if the printed patterns are in contact, it will be determined to be normal, reducing the inspection accuracy. Furthermore, in the case where the printed pattern on the front side of the board and the printed pattern on the back side are connected by a through hole, an ITV camera can only detect the printed pattern on one side and cannot detect a disconnection at the through hole. Furthermore, in multilayer printed wiring boards, intermediate layers cannot be inspected.

[Object of the Invention] The present invention has been made based on the above-mentioned circumstances, and its object is to provide a pattern inspection device that can quickly inspect the condition of a printed pattern even on a multilayer printed wiring board.

(Summary of the Invention) The present invention applies heat to a printed pattern using a heating means, receives radiant heat from the printed pattern at this time, and obtains temperature distribution information of the printed pattern.
This pattern inspection apparatus attempts to achieve the above objective by comparing this temperature distribution information with normal temperature distribution information according to a printed pattern and performing an inspection.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to a configuration diagram of a pattern inspection apparatus.

In the figure, 1 indicates print patterns p1, p2,...p
6 is a printed wiring board.

Note that this printed wiring board 1 may have multiple layers. Now, in order to inspect each of the printed patterns p1 to p6 of this printed wiring board 1, a thermobin board 2 is arranged.

This thermobin board 2 has each print pattern p1~
Each heat transfer needle 3 made of metal is provided at each hole position of p6, for example, at a position corresponding to hl and h2 in the printed pattern p1. These heat transfer needles 3 are inserted into each hole of each of the printed patterns p1 to l)6 so as to be in contact with each other. Note that heat is transferred to each heat transfer needle 3 from a heater controller 4 containing a built-in heater. Reference numeral 5 denotes an X-7 table on which a printed wiring board 1 and a thermobin board 2 are placed, and these are moved in the X-axis direction and the Z-axis direction under the control of the X-7 table drive control section 6. I'm trying to make it possible.

Reference numeral 7 denotes a scanning thermometer, which is placed in front of the printed wiring board 1 and scans the radiant heat of the printed wiring board 1, that is, infrared rays, with respect to the printed wiring board 1, while e.g.
The nSb detector receives the heat and outputs an electrical signal corresponding to the amount of heat received.

The electrical signal output from the scanning thermometer 7 is converted into a digital signal, sent to an image memory 8, and stored as temperature distribution information of the entire printed wiring board 1. On the other hand, a normal temperature distribution map 9 is provided, in which normal temperature distribution information when each of the print patterns p1 to p6 is in a normal state is stored in advance. The main control unit 10 issues a command to the heater controller 4 to control the heating of each heat transfer needle 3 to a predetermined temperature, and also
-7 It has a function of issuing a position control signal to the table drive control section 6 to control the printed wiring board 1 so that it is placed at an appropriate position. Furthermore, this main control section 10 is equipped with the following functions. That is, image memory 8
This function is to check the state of each print pattern p1 to p6 by comparing the temperature distribution information stored in the normal temperature distribution map 9 with the normal temperature distribution information stored in the normal temperature distribution map 9. The printer 11 prints out the test results.

Next, the operation of the apparatus configured as described above will be explained.

The printed wiring board '1 to be inspected is placed on the x-7 table 5, and then the thermobin board 2 on which each heat transfer needle 3 corresponding to this printed wiring board 1 is placed is similarly placed on the x-7 table 5.
7 placed on the table 5, each heat transfer needle 3 is inserted into each hole and electrically connected. In this state, a command is issued from the main control section 10 and the heater controller 4
Each heat transfer needle 3 is heated to a predetermined temperature. As a result, heat is transferred to each of the print patterns p1 to p6, and the print patterns p1 to p6 are heated. Here, the scanning temperature side 7 receives the radiant heat (infrared rays) of each of the pudding patterns p1 to p6 and outputs an electric signal corresponding to the amount of radiation heat (-). At this time, the scanning thermometer 7
Since the entire printed wiring board 1 is scanned and electrical signals are sent out sequentially, when all scanning is completed, an electrical signal corresponding to the temperature distribution of the entire printed wiring board 1 is output. This electrical signal is converted into a digital signal and stored in the image memory 8.
The temperature distribution information is stored as temperature distribution information for print 1 to wiring board 1, especially for each print pattern p1 to p6. Now, here, the main control section 10 reads out the temperature information stored in the image memory 10 and compares it with the normal temperature information stored in the normal temperature map 9. Here, if there is a disconnection in the printed patterns p1 to p6, heat will not be transferred, and therefore the temperature distribution in this portion will be different from the normal temperature distribution. Also, pudding pattern p
If there are whiskers, cracks, chips, etc. in the intermediate position between 1 and p6, the temperature distribution will be different from the normal temperature distribution.

Thus, even in the multilayer printed wiring board 1, the temperature distribution will differ due to heat transfer. Therefore, the main control unit 10 inspects the state of each print pattern p1 to p6 by comparing the temperature distribution information and the normal temperature distribution information, and obtains the result. This test result is output to the printer 11 and printed out.

In this way, in the above embodiment, heat is applied to the print patterns p1 to p6, and the radiant heat of the patterns p1 to p6 is applied to the pudding 1 at this time, so that the print patterns p1 to p6 are heated.
In step 6, we determined the temperature distribution information of the pull pattern and compared this temperature distribution information with the normal temperature distribution information according to the patterns p1 to p6 for pudding 1.
Cracks, chips, scratches, contacts, disconnections, etc. in each of the printed patterns p1 to p6 can be reliably detected by only the inspection process, and even if the wiring board 1 is multilayered in the print 1, it can be reliably detected. Here, even if the pudding mill patterns are in contact with each other, heat is transferred through this contact portion, so that a temperature distribution different from the normal temperature distribution is exhibited, which can be reliably detected. In addition, the same print pattern? 1! If there are several broken wires, the number and location cannot be detected, but such cases are rare, and even if they are found, inspection will be performed by a separate means.

Note that the present invention is not limited to the above-mentioned embodiment, and can be modified without departing from the spirit thereof.

For example, one way to apply heat to each print pattern is to use only one heat transfer needle, place it on an X-7 table, and then move the X-7 table to apply heat to each print pattern individually. Alternatively, the temperature distribution may be determined by sequentially applying heat to the . This configuration is particularly effective when inspecting different print patterns one after another. Also for heat transfer! Instead of the contact method as in the case of 1, heat may be applied in a non-contact manner using a laser beam.

[Effect of the invention] ~9- As detailed above, according to the present invention, multilayer pudding 1~
It is possible to provide a pattern inspection device that can quickly inspect the condition of printed patterns even on wiring boards.

[Brief explanation of drawings]

The figure is a configuration diagram showing an embodiment of a pattern inspection device according to the present invention. DESCRIPTION OF SYMBOLS 1... Board, 2... Thermobin board, 3... Heat transfer needle, 4... Heater controller 1 roller, 5... X-
7 table, 7... scanning thermometer, 8... image memory, 9... normal temperature distribution map, 10... main control unit.

Claims (4)

[Claims] (1) a heating means that applies heat to a printed pattern; a temperature distribution detection means that receives radiant heat from the printed pattern and obtains temperature distribution information in the printed pattern;
A pattern inspection apparatus comprising: inspection means for performing an inspection by comparing temperature distribution information obtained by the temperature distribution detection means with normal temperature distribution information according to the printed pattern. (2) The pattern inspection device according to claim (1), wherein the heating means includes a number of heat transfer needles corresponding to the printed pattern in direct contact with the printed pattern. (3) The pattern inspection apparatus according to claim (1), wherein the heating means heats the printed pattern in a non-contact manner using a laser beam. (4) The pattern inspection device according to claim (1), wherein the temperature distribution detection means creates temperature distribution information based on an output electrical signal from a scanning thermometer that receives radiant heat.