JPH076755U - Defect detection device for detected object - Google Patents

Abstract

(57) [Abstract] [Purpose] To detect defects on the surface of pressure sensor element by laser light. A laser 1 is provided above a carrying member 6 for carrying a plurality of pressure sensor elements 12 and carrying it in a horizontal direction, and a concave lens 3, a collimating lens 4, and a cylindrical lens 5 are provided between the laser 1 and the carrying member 6. The lens system 2 is formed, and the shielding member 7 having the slit window 8 above the conveying member 6 and the line camera 9 above the conveying member 6 convey the optical axis of the line camera 9 and the slit window 8 of the shielding member 7. The vertical line of the detected body 12 on the member 6 is matched. The laser beam 1a oscillated from the laser 1 is formed into a slit shape by passing through the lens system 2, and is irradiated onto the surface of the detection target 12 in this state. When there are scratches, dust, etc. on the surface of the detected body 12, a part of the laser light 1a becomes scattered light 1b and is captured by the line camera 9 through the slit window 8.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a defect detection device for detecting the surface condition of a pressure sensor element, and in particular, a defect of an object to be detected using a laser which is effective for detecting defects such as scratches and dust on the order of microns and submicrons. The present invention relates to a detection device.

[0002]

[Prior art and its problems]

 Generally, in order to form a thin film such as a gauge film or an insulating film on the surface of a pressure sensor element, after the surface is machined to a mirror surface, the cutting debris and dust adhering to the surface are completely cleaned with a cleaning liquid. After removing it, a thin film is formed in the clean room by using a sputtering device or the like.

That is, when a thin film is formed on the surface of the pressure sensor element with scratches, dust, etc. still present, the insulation property of the insulating film is deteriorated, the gauge film is broken, and the resistance value is abnormal. Since good quality occurs frequently, the incidence of defects is usually reduced by forming a thin film in a clean room.

However, the surface of the pressure sensor element may be scratched for some reason during machining, and dust is not completely present even in a clean room. There is a possibility that dust generated from the surface or the like exists and adheres to the surface of the pressure sensor element.

Therefore, in the pre-stage of the thin film forming work, it is an important issue to properly grasp the surface condition of the pressure sensor element in order to improve the yield in the thin film forming work.

Conventionally, an operator visually checks the surface condition of the pressure sensor element. However, when the operator visually checks, the operator's experience and intuition are largely involved. If the person changes, the standard of grasping will change naturally, so it was not always possible to grasp the state of the surface of the pressure sensor element accurately.

[0007] Therefore, as a result of various trials and errors, a trial and error was made as to whether or not there is a method for easily and reliably detecting micron or submicron-order dust adhering to the surface of the pressure sensor element. We have come to the conclusion that the use of is most effective.

As a defect inspection apparatus using a laser, for example, one shown in FIG. 7 has been already known, and this defect inspection apparatus is for detecting a defect of the LSI wafer 20. When the surface of the LSI wafer 20 is irradiated with the laser light 22 from 21 and there is a scratch or dust on the surface of the LSI wafer 20, a part of the laser light 22 becomes the scattered light 23. When captured by the photoelectric element 26 via the convex lens 24 and the polarizing plate 25 located vertically above the laser beam 22 and the surface of the LSI wafer 20 is free from scratches or dust, the laser light 22 is totally reflected and photoelectrically converted. It utilizes what the element 26 cannot capture.

However, in such a defect inspection apparatus, since the laser beam 22 is used, it is possible to easily and surely detect defects due to scratches or dust on the order of micron or submicron. However, since only one point of the LSI wafer 20 can be detected in one detection operation, in order to detect the entire surface of the LSI wafer 20, the laser 21 must be detected while scanning in the XY directions. A device for moving the z-axis 21 in the XY directions is required, which makes the whole complicated and the detection work becomes complicated. Furthermore, since it is not possible to continuously inspect a plurality of LSI wafers 20, work efficiency is very poor.

The present invention solves the above-mentioned problems of the conventional ones, and can reliably detect defects such as scratches and dust generated on the surface of the object to be detected, and at the same time, can provide a laser. An object of the present invention is to provide a defect detection device for an object to be detected, which is capable of continuously detecting a plurality of objects to be detected without moving the object, and can also be used for managing a clean room. Is.

[0011]

[Means for solving problems]

 In order to solve the above-mentioned problems, the present invention provides a carrier member on which a plurality of objects to be detected are continuously carried and a laser capable of oscillating a laser beam arranged above the carrier member. A lens system for diffusing and converging laser light oscillated from this laser to form an appropriate slit shape, and irradiating the object to be detected on the carrying member with the lens system; and a lens system provided above the carrying member. A shielding member having a slit window formed on the vertical line of the detected object, and a line camera arranged above the shielding member so that the optical axis thereof coincides with the vertical line of the detected object. When laser light oscillated from the laser is applied to the object to be detected through the lens system and there are scratches, dust, etc. on the object to be detected, a part of the laser light is included. Becomes scattered light through the slit window of the shielding member. It is obtained by employing means that are captured by the line cameras Te.

[0012]

[Action]

 By adopting the above-mentioned means in this invention, the laser light emitted from the laser is diverged and converged by the lens system to be formed into an appropriate slit shape, and in this state, it is irradiated to the detection object of the transfer member. If there are scratches, dust, etc. on the detected object, part of the laser light becomes scattered light and is captured by the line camera through the slit window of the shielding member. Therefore, by detecting whether or not the line camera captures the scattered light, it is possible to detect whether or not there are scratches, dust, etc. on the surface of the detection target. By performing such an operation while transporting a plurality of detected objects by the transport member, it is possible to continuously detect the presence of scratches, dust, etc. on the plurality of detected objects.

[0013]

【Example】

 An embodiment of the present invention shown in the drawings will be described below. FIG. 1 shows a schematic view of an embodiment of the defect detecting apparatus for a detected object according to the present invention. A conveying member 6 for conveying in a horizontal direction, a laser 1 arranged obliquely above the conveying member 6 and capable of oscillating laser light 1a, and a laser 1 arranged between the laser 1 and the conveying member 6. The laser system 1 a oscillated from 1 is diffused and converged to form an appropriate slit shape, and the lens system 2 for irradiating the detection target 12 on the conveying member 6 is provided above the detection target 12. The shielding member 7 having a slit window 8 formed on the vertical line of the detected body 12 and the shielding member 7 are arranged above the shielding member 7 so that the vertical line of the detected body 12 and the optical axis thereof coincide with each other. A line camera 9 and a computer for processing the image captured by the line camera 9. And it includes the emissions 10.

The lens system 2 is configured as shown in FIGS. 2 and 3, FIG. 2 is a side view, FIG. 3 is a plan view, and FIG. 4 shows the laser beam 1 a passing through the lens system 2. It is explanatory drawing which showed the shape. That is, the lens system 2 is composed of a concave lens 3, a collimating lens 4, and a cylindrical lens 5. The concave lens 3, the collimating lens 4, and the cylindrical lens 5 are provided in this order from the laser 1 side, and the laser 1 oscillates. The laser beam 1a thus diffused is diffused by the concave lens 3 and is collimated by the collimating lens 4 in parallel, and then is condensed by the cylindrical lens 5 in only one axial direction to be formed into a slit shape.

Next, the operation of the above will be described. First, the defect detection device for an object to be detected configured as described above is located in the clean room 15, and the interior of the clean room 15 is set as a dark room as necessary to eliminate the influence of light.

Then, the laser light 1 a is oscillated from the laser 1, diffused by the concave lens 3 of the lens system 2, converged in parallel by the collimator lens 4, and collimated by the cylindrical lens 5 in only one direction. The laser beam 1a formed into the light 1a and formed into the slit shape is applied to the surface formed on the mirror surface of the pressure sensor element 12, which is the object to be detected, on the transport member 6 (see FIGS. 1 and 5).

Here, the focus of the cylindrical lens 5 is adjusted to increase the irradiation density of the laser light 1 a on the surface of the pressure sensor element 12.

That is, since the intensity of scattered light 1b, which will be described later, is proportional to the sixth power of the particle size of scratches, dust, etc., microscopic scratches of the micron and sub-micron order, which are problems in the thin film forming work of the pressure sensor element 12, In order to detect defects such as dust, it is necessary to increase the intensity of the laser beam 1a and focus the cylindrical lens 5 to increase the irradiation density, and to detect the minute scratches and dust described above. In such a case, the scattered light 1b becomes extremely weak, so it is necessary to detect the inside of the clean room 15 by making it a dark room in order to eliminate the influence of the light in the room.

As shown in FIG. 6, when there are scratches 14, dust 13, etc. on the surface of the pressure sensor element 12, a part of the slit-shaped laser light 1a becomes scattered light 1b, and this scattered light 1b is generated. The light 1b is captured by the line camera 9 through the slit window 8 of the shielding member 7 located vertically above the pressure sensor element 12. In this case, dust 13 is also present on the path of the laser beam 1a, and when the dust 13 hits the laser beam 1a, scattered light 1b is also generated. However, the scattered light 1b is blocked by the blocking member 7. Therefore, the scattered light 1b does not reach the line camera 9, and only the scattered light 1b on the optical axis of the line camera 9, that is, the scattered light 1b caused by defects such as scratches 14 on the surface of the pressure sensor element 12 and dust 13 is generated. Will be captured by the line camera 9.

On the other hand, when the surface of the pressure sensor element 12 is free of scratches 14, dust 13, etc., the slit laser light 1a is totally reflected by the surface formed on the mirror surface of the pressure sensor element 12, and the line camera I can't catch it in 9.

Therefore, if the scattered light 1b captured by the line camera 9 is image-processed by the personal computer 10, it is possible to easily detect whether or not there is a defect such as a scratch 14 or dust 13 on the surface of the pressure sensor element 12. In addition, it is possible to identify the defective portion due to the scratches 14, dust 13, etc., and it is also possible to estimate the particle size of the scratches 14, dust 13, etc. to some extent, which is the cause of the failure occurrence. It will be possible to investigate. If the defective product discharging device 11 is connected to the personal computer 10, the defective product captured by the line camera 9 can be easily discharged.

By performing the above-mentioned work while operating the conveying member 6, it is possible to easily and surely detect defects on the entire surface of the pressure sensor element 12 without moving the lens system 2. You can By continuously performing such an operation, it becomes possible to continuously detect defects on the surface of the plurality of pressure sensor elements 12.

Furthermore, by detecting the state of the dust 13 adhering to the surface of the pressure sensor element 12 as described above, the generation state of the dust 13 in the clean room 15 can be accurately grasped, so the clean room 15 It is also possible to control the above, and it is possible to significantly reduce the occurrence of defective products in the thin film forming process of the pressure sensor element 12, and it is possible to significantly increase the yield.

In the above description, the line camera 9 is used to capture the scattered light 1b, but a photon detector tube (MCP) is added to the line camera 9 to detect finer defects. If it is not necessary to specify the defect position, a photoelectron amplifier tube may be used in place of the line camera 9, and an appropriate one may be selected and used according to the application. It ’s good.

[0025]

[Effect of device]

 With this configuration, the invention can accurately grasp the surface condition of the object to be detected by detecting the condition of the laser beam applied to the surface of the object to be detected. That is, if the surface of the object to be detected has defects such as scratches and dust, part of the laser light becomes scattered light and is captured by the line camera. Therefore, whether the line camera can capture scattered light or not. If it is detected, the surface condition of the object can be accurately determined. Therefore, when a thin film is to be formed on the surface of the object to be detected, the state of the object to be detected can be accurately grasped at the previous stage, and the generation of defective products due to scratches, dust, etc. can be significantly reduced. Therefore, the yield can be significantly improved. Further, by carrying out the above-mentioned work while the plurality of objects to be detected are carried by the carrying member, the defects of the plurality of objects to be detected can be continuously inspected, and the workability is remarkably improved. Further, it has an excellent effect that the clean room can be managed by grasping the state of adhesion of the dust.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of a defect device for a detected object according to the present invention.

FIG. 2 is a side view of the lens system shown in FIG.

3 is a plan view of the lens system shown in FIG. 1. FIG.

FIG. 4 is a diagram illustrating the shape of laser light that has passed through each lens of the lens system.

FIG. 5 is a diagram showing a state in which the surface of the object to be detected is irradiated with laser light.

FIG. 6 is a partial cross-sectional view showing a state where scratches, dust, and the like are present on the detected object.

FIG. 7 is a schematic diagram showing an example of a conventional defect detection device.

[Explanation of symbols]

 1, 21 ... Laser 2 ... Lens system 3 ... Concave lens 4 ... Collimating lens 5 ... Cylindrical lens 6 ... Conveying member 7 ... Shielding member 8 ... Slit window 9 ... Line camera 10 ... PC 11 …… Defective product discharging device 12 …… Detected object (pressure sensor element) 13 …… Dust 14 …… Scratch 15 …… Clean room 1a, 22 …… Laser light 1b, 23 …… Scattered light 20 …… LSI wafer 24… … Convex lens 25 …… Polarizer 26 …… Photoelectric element

Claims (1)

[Scope of utility model registration request] 1. A carrier member (6) for continuously carrying a plurality of objects to be detected (12) placed thereon and a laser beam (1a) arranged above the carrier member (6). A possible laser (1) and a laser beam (1a) oscillated from the laser (1) are diffused and converged to form an appropriate slit shape, and an object to be detected (12) on the carrying member (6) is formed. The lens system (2) for irradiating the object and the shielding member (7) arranged above the transport member (6) and having a slit window (8) formed on the vertical line of the object (12) to be detected. ) And a line camera (9) arranged above the shielding member (7) so that the optical axis thereof coincides with the vertical line of the detected body (12), and oscillates from the laser (1). When the irradiated laser beam (1a) is applied to the object (12) through the lens system (2) When there are scratches, dust, etc. on the detected body (12), a part of the laser light (1a) becomes scattered light (1b) and the slit window (8) of the shielding member (7) is passed through. A defect detection device for an object to be detected, which is captured by the line camera (9) through the line camera (9).