JP6906339B2 - Semiconductor inspection equipment and semiconductor inspection method - Google Patents

Description

The present invention relates to a semiconductor inspection apparatus and a semiconductor inspection method for inspecting the quality of a semiconductor element after energization.

In the conventional discoloration inspection method, the object is irradiated with white light, and the degree of discoloration of the object is determined using the feature amount of the image data obtained by imaging by the imaging means to determine the quality of the object. (See, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2003-216930

In the energization test that evaluates the electrical characteristics of a semiconductor element, the current density is locally concentrated and the temperature rises excessively, and the cooling performance deteriorates and the self-heating of the semiconductor element cannot be completely cooled and heat is generated. As a result, the semiconductor element may be discolored by the oxide film. Further, in the manufacturing process of the semiconductor element, the semiconductor element may be dented or scratched due to the dent. In the process of inspecting the quality of a semiconductor element, it is necessary to determine that the semiconductor element containing scratches is a good product and the semiconductor element containing discoloration due to an oxide film is a defective product in consideration of the influence on the bondability at the time of assembly. However, in the discoloration inspection method described in Patent Document 1, since the feature amounts of the oxide film and the scratches are similar in the image data obtained by imaging, the semiconductor element including the discoloration due to the oxide film and the semiconductor containing the scratches. Both elements were judged to be defective. Therefore, there is a problem that only the semiconductor element including discoloration due to the oxide film cannot be determined as a defective product, and the accuracy of inspecting the semiconductor element is lowered.

The present invention has been made to solve the above problems, and when inspecting the quality of a semiconductor element, the semiconductor element is inspected by determining only the semiconductor element including discoloration due to an oxide film as a defective product. The purpose is to improve the accuracy of the device.

The semiconductor inspection apparatus in the present invention inspects whether or not the surface of a semiconductor element after energization is discolored by an oxide film, and is an imaging unit provided at a position facing the surface, and the surface and the imaging unit. A first irradiation unit that is provided between the two and irradiates the surface with light containing the first wavelength, and a second wavelength different from the first wavelength from a direction different from the light containing the first wavelength. Acquires image data by reflected light including a second irradiation unit that irradiates a surface with light containing the light, reflected light from a surface based on the first wavelength, and reflected light from a surface based on the second wavelength. and, based on the height of the contrast of the image data obtained is an oxide film region is an image region showing a color change due to oxidation film from among the image data that includes an image processing unit to identify.

The semiconductor inspection apparatus according to the present invention improves the accuracy of inspecting semiconductor elements.

It is a perspective view of the semiconductor inspection apparatus in Embodiment 1 of this invention. It is sectional drawing of the energized part of the semiconductor inspection apparatus in Embodiment 1 of this invention. It is a figure which shows the operation of the energization test in Embodiment 1 of this invention. It is a figure which shows the operation of the energization test in Embodiment 1 of this invention. It is sectional drawing of the inspection part of the semiconductor inspection apparatus in Embodiment 1 of this invention. It is a figure which shows the image data in Embodiment 1 of this invention. It is a figure which shows the inspection algorithm of the semiconductor element in Embodiment 1 of this invention. It is sectional drawing of the inspection part of the semiconductor inspection apparatus in Embodiment 2 of this invention.

Embodiment 1.
The semiconductor inspection apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 7. FIG. 1 is a perspective view of the semiconductor inspection device according to the first embodiment, and FIG. 2 is a cross-sectional view of an energized portion of the semiconductor inspection device.

As shown in FIG. 1, the semiconductor test apparatus 100 includes a base 1, a transfer mechanism 2 in the Y direction, a transfer table 3, an energizing unit 4, a cooling plate 5, a probe 6, a pressure plate 7, a servo press 8, a support column 9, and a power supply. 10, PLC11, screen 12, press controller 13, power supply controller 14, suction pad 21, imaging unit 22, first irradiation unit 23, second irradiation unit 24, light-shielding wall 25, inspection unit 26, transfer mechanism in the Z direction. 27 and a transfer mechanism 28 in the X direction are provided. The semiconductor test apparatus 100 is an apparatus used for evaluating the electrical characteristics of the semiconductor element 15 used in the application of passing a large current.

The base 1 is provided with a transport base 3, a probe 6, a pressure plate 7, a servo press 8, and a support column 9 for performing an energization test of a semiconductor element. An energizing unit 4 to be energized and pressurized is mounted on the transport table 3. Further, a transfer mechanism 28 in the X direction, a transfer mechanism 2 in the Y direction, and a transfer mechanism 27 in the Z direction for transferring the transfer table 3 after the energization test to the inspection unit 26 are provided. Further, a suction pad 21 for sucking the semiconductor element 15 and transferring it to the inspection unit 26 is provided. The transfer mechanism 28 in the X direction, the transfer mechanism 2 in the Y direction, and the transfer mechanism 27 in the Z direction are composed of a rail and a block, and an actuator is used as a mechanism in which the block on which the semiconductor element is mounted slides on the rail. The semiconductor element 15 is transferred from the energizing unit 4 toward the inspection unit 26 by the above-mentioned transfer mechanism. Further, the base 1 is provided with an inspection unit 26 for a semiconductor element. In the present embodiment, the base 1, the transport base 3, and the support 9 are made of a material including aluminum parts, but any material having durability and wear resistance may be used, for example, iron or stainless steel. (SUS), plastic and the like are used.

As shown in FIG. 2, the energizing unit 4 is provided in a guide 19 for positioning the semiconductor element 15, a hole 19a provided in the guide 19, a cooling plate 5 arranged on the back surface of the guide 19, and a cooling plate 5. The convex portion 5a, the third interleaving material 16 arranged between the semiconductor element 15 and the cooling plate 5, the second interleaving material 17 arranged so as to cover the semiconductor element 15 across the guide 19, and the second interleaving material. A first interstitial material 18 is provided which is placed on the material 17 so as to cover the semiconductor element 15.

The semiconductor element 15 is an object to be energized, and has electrodes on at least the front surface 35, which is the first main surface thereof, and the back surface 36, which is the second main surface facing the surface 35. A fine circuit pattern is formed on the surface 35. As the semiconductor element 15, for example, a Schottky barrier diode using silicon carbide, a MOSFET (Metal-Oxide-Semiconductor Field-Effective-Transistor), and the like can be considered.

The first interstitial material 18 may have a size equal to or larger than that of the semiconductor element 15, but is preferably thicker from the viewpoint of durability. Further, since the first interstitial material 18 has a portion in contact with the probe 6, it is preferable to reduce the surface roughness by polishing in order to increase the contact area between the probe 6 and the semiconductor element 15. Further, the first interstitial material 18 has a role of absorbing the deviation of the parallelism between the bottom surface of the lowered probe 6 and the semiconductor element 15 and improving the parallelism between the two. In particular, when a probe 6 composed of a plurality of probes 6 is used, the length of the probe 6 varies, so that the first interstitial material 18 needs to have a certain thickness in order to make the pressing force uniform. If the first interstitial material 18 is thin, it is easily plastically deformed, so that the uniformization of the pressing force is inferior, the element is easily damaged and local current concentration is likely to occur, and the semiconductor element 15 is discolored by the oxide film. It is more likely to occur.

The second interleaving material 17 may have a size that can cover the semiconductor element 15, but with respect to the thickness, it absorbs a step of several μm such as an electrode pattern formed on the surface 35 of the semiconductor element 15. It is necessary to have a thickness that allows it to be used. If the thickness of the second interleaving material 17 is not sufficient, the aluminum interleaving material or the cooling plate may break during the energization test, and the energization test may fail. Further, if the thickness of the second interstitial material 17 is too large, thermal expansion increases in the rolling direction due to heat generated during energization and pressurization, and the semiconductor element 15 is likely to be scratched due to the difference from the thermal expansion of the semiconductor element 15. Become. Further, due to the increased rigidity, voids are formed due to deformation according to the shape of the surface of the semiconductor element 15 during pressurization, and the heat dissipation is deteriorated, so that the back surface 36 of the semiconductor element 15 is discolored by the oxide film. It will be easier.

The second interleaving material 17 is connected to the electrode on the side opposite to the electrode connected to the third interleaving material 16 via the first interleaving material 18, and the power source 10 is energized to the semiconductor element 15. Therefore, it comes into contact with the electrode on the surface 35 of the semiconductor element 15.

The third interleaving material 16 is in contact with the electrode on the back surface 36 of the semiconductor element 15, and the electrode on the back surface 36 of the semiconductor element 15 and the power supply 10 are connected to each other. That is, the third intermediate material 16 is connected to the positive electrode or the negative electrode of the power supply 10 via the cooling plate 5.

The material of the first interstitial material 18, the second interstitial material 17, and the third interstitial material 16 may be any material having high electrical conductivity, heat resistance, and abrasion resistance, for example. , Copper, aluminum, etc. are used.

The cooling plate 5 is provided on the back surface 36 side of the semiconductor element 15, and is a member for cooling the semiconductor element 15 that has generated heat when the semiconductor test apparatus 100 performs an energization test. The cooling plate 5 is a plate-shaped member having a rectangular planar shape, and a semiconductor element 15 is placed via a third interstitial material 16. The heat generated at the time of energization of the semiconductor element 15 positioned by the guide 19 is cooled by being transmitted through the convex portion 5a provided in the central portion of the cooling plate 5 via the third intermediate member 16. The cooling plate 5 may be a substance having high conductivity and thermal conductivity, heat resistance and abrasion resistance, and for example, copper, aluminum, carbon and the like are used.

The probe 6 is arranged on the first interstitial material 18 in order to pass a large current through the semiconductor element 15 by coming into contact with the first interstitial material 18 and acquire a response signal from the semiconductor element 15. There is. The probe 6 is fixed to the pressure plate 7 so as to extend along the Z direction, and has a cylindrical shape, for example. The probe 6 is generally made of carbon tool steel such as tungsten, but the material constituting the probe 6 is not limited to this. The probe 6 may be a substance having high conductivity, heat resistance and abrasion resistance, and a constant load capacity for pressurization, and for example, gelacon, brass, stainless steel, or the like may be used. As long as the probe 6 can withstand the load and current density per probe, one probe may be energized and pressurized, or a plurality of probes 6 may be energized and pressurized.

The same applies to the material constituting the pressure plate 7, and it is preferable that the material is made of carbon tool steel, but the material constituting the pressure plate 7 is not limited to this. The pressure plate 7 may be a substance having high conductivity, heat resistance and abrasion resistance in order to electrically connect to the probe 6 and cool the generated probe 6, for example, copper or aluminum. May be used.

The guide 19 is provided with a hole 19a for positioning the semiconductor element 15 and the third intermediate member 16. The material constituting the guide 19 may be a substance having insulating properties, heat resistance, and abrasion resistance in order to prevent the current supply to the semiconductor element 15 from splitting, and for example, copper, aluminum, or the like is used. .. The guide 19 is not limited to the ceramic polymer material, and a metal material coated with insulation may be used. For example, a metal material wrapped with insulating tape, a ceramic coating, a glass coating, or the like can be mentioned. As a result, it is possible to inexpensively reduce causes that adversely affect the energization test process, such as current shunting.

Next, the energization test of the semiconductor element in the semiconductor inspection apparatus configured as described above will be described with reference to FIGS. 1, 3, and 4.

FIG. 3 is a diagram showing the operation of the energization test. First, as shown in FIG. 3A, the third intermediate member 16 is positioned and arranged on the cooling plate 5 by the guide 19. Next, as shown in FIG. 3B, the semiconductor element 15 is arranged on the third interstitial material 16. Subsequently, FIG. 3 (c)
As shown in the above, the second interstitial material 17 is arranged so as to cover the semiconductor element 15 across the guide 19. Further, as shown in FIG. 3D, the first interleaving member 18 is arranged so as to overlap the second interleaving member 17 and cover the semiconductor element 15.

As shown in FIG. 1, the semiconductor test apparatus 100 is under the servo press 8 by the transfer mechanism 2 in the Y direction composed of an actuator or the like, that is, a pressure plate, with the energizing unit 4 mounted on the transfer table 3. The transfer table 3 can be transferred to the bottom of the probe 6 and the probe 6. When transferring the transport table 3, for example, GOT (Graphic Operation Thermal) (registered trademark) is used as the screen 12 for operation. The instruction information for transferring the transfer table 3 on the screen 12 is converted into a control signal of the transfer mechanism 2 in the Y direction in the PLC (Programmable Logical Controller) 11, and the transfer table 3 is transferred by the transfer mechanism 2 in the Y direction. ..

FIG. 4 is a diagram showing the operation of the energization test. As shown in FIG. 4A, initially the probe 6 is not in contact with the first interstitial material 18 arranged in the energized portion 4. Next, as shown in FIG. 4B, the servo press 8 supported by the support column 9 presses the pressurizing plate 7 by reading the conditions preset by the press controller 13 based on the control information from the PLC 11. It descends toward the energized portion 4 on the transport table 3, and the probe 6 comes into contact with the first interstitial material 18 arranged in the energized portion 4. After that, according to the instruction from the PLC 11, the pressing force of the probe 6 is raised to an arbitrarily set specified load value (25 kg to 100 kg), and then the power supply is read by reading the preset conditions in the power supply controller 14. A current arbitrarily set from 10 (current density of 120 [A / cm ² ] or more and less than 400 [A / cm ² ]) is continuously passed through the energizing unit 4. At that time, the temperature of the semiconductor element 15 is set to 150 ° C. or higher and 230 ° C. or lower.

The semiconductor test apparatus 100 constantly monitors the temperature of the semiconductor element 15 under energization and pressurization by the PLC 11 using a thermocouple attached to the convex portion 5a of the cooling plate 5, and has a specified temperature (150 ° C. or higher and 230 ° C. or lower). ), The PLC 11 has a function of transmitting a signal for stopping the energization and pressurization to the press controller 13 and the power supply controller 14 to stop the energization and pressurization.

Further, in the semiconductor test apparatus 100, when the current density is ^{out of the range of 120 [A / cm 2} ] or more and less than 400 [A / cm ² ], the semiconductor element 15 being energized and pressurized by the power controller 14 is defective. Judge as. The determination result is transmitted to the PLC 11, and a signal for stopping the energization pressurization is transmitted by the PLC 11 to the press controller 13 and the power supply controller 14, and has a function of stopping the energization pressurization. Damage to peripheral mechanisms can be suppressed by the function of stopping energization and pressurization when an abnormality occurs.

Subsequently, a method of detecting discoloration due to the oxide film on the back surface 36 of the semiconductor element 15 after energization will be described with reference to FIGS. 5 and 6.

FIG. 5 is a cross-sectional view of an inspection unit of the semiconductor inspection apparatus. As shown in FIG. 5, the inspection unit 26 includes a suction pad 21 for sucking the front surface 35 of the semiconductor element 15, an image pickup unit 22 facing the back surface 36 of the semiconductor element 15, a first irradiation unit 23, and a second. It includes an irradiation unit 24, a light-shielding wall 25, and an image processing unit 29. First, the suction pad 21 sucks the semiconductor element 15. The back surface 36 of the semiconductor element 15 that is lifted and stopped in a hollow state while maintaining the adsorption state is shielded from the influence of ambient light by a light-shielding wall 25. The light-shielding wall 25 can be replaced with a blackout curtain or the like.

Next, the first irradiation unit 23 containing the light of the first wavelength and the second irradiation unit 24 containing the light of the second wavelength are simultaneously irradiated toward the semiconductor element 15. The light having the first wavelength is light that predominantly contains light in a wavelength range of less than 380 nm, and is, for example, ultraviolet light (UV light) or far ultraviolet light (DUV light). The light having a second wavelength is light that predominantly contains light in a wavelength range of 380 nm or more and less than 780 nm, and is, for example, visible light. The first irradiation unit 23 irradiates the semiconductor element 15 from between the image pickup unit 22 and the semiconductor element 15, and the second irradiation unit 24 irradiates the semiconductor element 15 from an oblique direction different from the light including the first wavelength. do. The first irradiation unit 23 may irradiate the semiconductor element 15 from between the image pickup unit 22 and the semiconductor element 15. For example, a half mirror is installed between the image pickup unit 22 and the semiconductor element 15, and the half mirror is installed. A coaxial lighting device that irradiates light through the light is used. Instead of the half mirror, a branching optical element such as a beam splitter that can split the luminous flux may be used.

The first irradiation unit 23 and the second irradiation unit 24 irradiate light having a desired wavelength by, for example, LED illumination. However, the first irradiation unit 23 and the second irradiation unit 24 are not limited to this. For example, it may be configured by a combination of white LED lighting and a color filter, or a combination of a white light bulb or a fluorescent tube and a color filter, a color lamp, or the like may be used. Further, the second irradiation unit 24 may appropriately use light having a specific wavelength such as red, green, or blue, depending on the characteristics of the oxide film region 31 and the scratched region 32. By using light of a specific wavelength, the reflected light from the oxide film region 31 and the scratched region 32 is emphasized, so that the accuracy of detecting the above-mentioned region can be improved.

The back surface 36 of the semiconductor element 15 is imaged by using the imaging unit 22 arranged in the inspection unit 26. As for the spectral sensitivity characteristic of the imaging unit 22, the sensitivity in the visible light wavelength region is higher than the sensitivity in the ultraviolet light wavelength region. The imaging unit 22 captures the reflected light from the back surface 36 including the reflected light from the back surface 36 based on the first wavelength and the reflected light from the back surface 36 based on the second wavelength, and the image obtained by imaging. The data is acquired by the image processing unit 29. The reflected light from the back surface 36 based on the first wavelength is light that predominantly contains specular reflected light. Further, the reflected light from the back surface 36 based on the second wavelength is light that predominantly contains diffuse reflected light. The image data refers to data indicating the brightness and darkness of each pixel constituting the image.

FIG. 6 is a diagram showing image data obtained by imaging. As shown in FIG. 6, the image data is divided into at least one of the oxide film region 31, the scratched region 32, and the normal region 33 in the determination unit provided in the image processing unit 29. The oxide film region 31 is a region showing discoloration due to the oxide film generated in the semiconductor element 15. The scratched area 32 is an area showing a scratch including a dent or a dent. The normal region 33 indicates a region other than the oxide film region 31 and the scratched region 32, and is a region having a flat shape without unevenness in the semiconductor element 15.

The determination unit provided in the image processing unit 29 identifies at least the oxide film region 31 among the oxide film region 31, the scratched region 32, and the normal region 33 based on the feature amount of the obtained image data, and is a semiconductor element. The quality of 15 is judged. The identification of the image region is normal, for example, if the data value of each pixel of the image data is within the threshold value of the oxide film, the oxide film region 31, the scratch region 32 if the data value is within the threshold value of the oxide film, and if it is outside the threshold value Identify as region 33. Since these threshold values change depending on the characteristics of the imaging unit 22, the first irradiation unit 23, and the second irradiation unit 24, it is desirable to determine them after considering the characteristics of the imaging unit and the illumination in advance. Based on the identification result, if the image data does not include the oxide film region 31, it is determined that the semiconductor element 15 is a non-defective product, and if the image data includes the oxide film region 31, the semiconductor element 15 is a defective product. Judge that there is.

It is understood that the reason why the obtained image data is divided into the oxide film region 31, the scratched region 32, and the normal region 33 in this way is as follows. As for the spectral sensitivity characteristic of the imaging unit 22, since the sensitivity in the ultraviolet light wavelength region is lower than the sensitivity in the visible light wavelength region, the first irradiation unit 23 is irradiated from between the imaging unit 22 and the semiconductor element 15, and the imaging unit 22 is irradiated. When the back surface 36 of the semiconductor element 15 is imaged with 22, image data having low contrast that can distinguish the region including the oxide film region 31 and the scratched region 32 from the normal region 33 can be obtained. However, since the contrast of the image data is low, it is difficult to distinguish between the oxide film region 31 and the scratched region 32.

The reason is that when the first irradiation unit 23 is irradiated toward the back surface 36 of the semiconductor element 15, in the obtained image data, the scratched region 32 on the back surface 36 of the semiconductor element 15 is diffused reflected by the imaging unit 22. This is because the brightness information is not included in a distinguishable manner. Further, when the first irradiation unit 23 is irradiated toward the back surface 36 of the semiconductor element 15, in the obtained image data, the oxide film region 31 on the back surface 36 of the semiconductor element 15 is the light in the ultraviolet wavelength region. This is because the absorption rate is higher than the absorption rate of light in the ultraviolet light wavelength region in the scratched region 32, so that information on the brightness of the oxide film region 31 cannot be obtained so as to be distinguishable. Therefore, in either the scratched region 32 or the oxide film region 31, the brightness information cannot be obtained so as to be distinguishable, and the contrast between the two becomes low.

In order to increase the contrast of the obtained image data, at the same time as the irradiation by the first irradiation unit 23, the semiconductor element 15 is irradiated with the second irradiation unit 24 from an oblique direction different from the light including the first wavelength. As a result, brightness information is added to the uneven scratched area 32. However, in the semiconductor element 15, the oxide film has a flat shape without unevenness, and light from an oblique direction different from the light including the first wavelength is totally reflected and reflected to the diagonal side of the semiconductor element 15. Information on the brightness of the scratched region 32 is not added to the oxide film region 31. Therefore, by irradiating the first irradiation unit 23 and the second irradiation unit 24 toward the semiconductor element 15 at the same time, there is a contrast between the scratched region 32 and the oxide film region 31 in the image data. Occurs. Further, since the normal region 33 has a flat shape without unevenness, the contrast between the scratched region 32 and the oxide film region 31 is increased in order to obtain information on the brightness more than the scratched region and the oxide film region. can get. Thereby, the oxide film region 31, the scratched region 32, and the normal region 33 can be detected.

Based on the detection result, if the image data does not include the oxide film region 31, it is determined that the semiconductor element 15 is a non-defective product, and if the image data includes the oxide film region 31, the semiconductor element 15 is a defective product. Judge that there is. The determination result is converted into an image signal through a processing circuit connected to the PLC 11, and is displayed on the screen 12 by characters or an image.

Based on the above, by using this configuration, the first irradiation unit 23 containing the light of the first wavelength and the second irradiation unit 24 containing the light of the second wavelength simultaneously irradiate the semiconductor element 15. Then, from the image obtained by imaging, only the oxide film region 31 of the semiconductor element 15 can be detected by utilizing the difference in contrast between the regions. Further, the oxide film region 31, the scratched region 32, and the normal region can be detected separately.

Next, an inspection algorithm when a gradation is generated on the back surface 36 of the semiconductor element will be described with reference to FIG. 7.

FIG. 7 is a diagram showing an inspection algorithm for a semiconductor element. FIG. 7A is image data showing the semiconductor element 15. As shown in FIG. 7A, since the back surface 36 of the semiconductor element 15 is polished, a gradation 34 may occur in the normal region 33 of the back surface 36 of the semiconductor element 15. When the normal region 33 cannot be detected due to the occurrence of the gradation 34, the normal region 33 is detected by performing the dynamic binarization process.

FIG. 7B is an example of image data before and after the dynamic binarization process. FIG. 7B shows that the image data after the dynamic binarization process has a higher contrast than the image data before the dynamic binarization process.

The dynamic binarization process will be described below. In the first embodiment, the dynamic binarization threshold value is defined as a value of a certain ratio of the average pixel value of the M × N pixels around the central pixel. In the first embodiment, 5 × 5 pixels around the center pixel are set as the target range, and a certain ratio is set to be 80% of the average pixel value. It is desirable that the size of the M × N pixel is set in consideration of the characteristics of the gradation 34. Further, it is desirable to set the shape of the peripheral pixels in consideration of the characteristics of the gradation 34 such as a cross shape, a cross shape, or a rectangle.

FIG. 7C is a diagram showing a first example of the dynamic binarization process, and FIG. 7D is a diagram showing a second example of the dynamic binarization process.

As shown on the left side of FIG. 7C, the central pixel shows the oxide film region 31, and the pixel value is 20. The average pixel value of the 5 × 5 pixels around the central pixel is 243, and the dynamic binarization threshold is 194. Therefore, as shown on the right side of FIG. 7C, in the central pixel and its peripheral pixels, the pixel value of the pixel whose pixel value is within the dynamic binarization threshold is converted to 0, and the pixel value is dynamically binary. The pixel value of the pixel outside the valuation threshold is converted to 255.

Further, as shown on the left side of FIG. 7D, the central pixel and the 5 × 5 pixels around it indicate the normal region 33, and their pixel values are 127. The average pixel value of the 5 × 5 pixels around the central pixel is 127, and the dynamic binarization threshold is 102. Therefore, as shown on the right side of FIG. 7D, since the pixel values of all the pixels in the central pixel and its peripheral pixels are outside the dynamic binarization threshold, the pixel values of these pixels are converted to 255. ..

By performing the above dynamic binarization process, the influence of the gradation 34 generated on the normal region 33 of the back surface 36 of the semiconductor element 15 can be suppressed, and the oxide film region 31 can be stably detected.

As described above, the semiconductor element 15 is oxidized by including the first irradiation unit 23, the second irradiation unit 24, and the image pickup unit 22 that captures the reflected light from the semiconductor element 15 irradiated by these illuminations. Only the semiconductor element 15 including discoloration due to the film can be determined as a defective product, which has the effect of improving the accuracy of inspecting the semiconductor element 15.

Further, when the dynamic binarization process is performed near the boundary between the semiconductor element 15 and the outside of the semiconductor element 15, the pixel value outside the semiconductor element 15 becomes lower than the pixel value of the semiconductor element 15, which is normal. The region 33 may be mistakenly detected as the oxide film region 31. On the other hand, by detecting the shape of the semiconductor element 15 in advance by an edge detection method, a pattern matching method, or the like and limiting the inspection range, erroneous detection can be suppressed.

In the first embodiment of the present invention, the determination result is shown on the screen 12 by characters or images, but the determination result may be shown by voice from the speaker. In this case, in an environment where the semiconductor test apparatus 100 and the screen 12 are separated from each other, it is possible to present information by voice.

Further, in the first embodiment of the present invention, the determination unit determines the quality of the semiconductor element 15, but instead of the determination unit, image data in which at least the oxide film region 31 is identified via the image processing unit 29. May be displayed on the screen 12. In this case, the mounting cost related to the determination process in the determination unit can be suppressed by determining the quality of the semiconductor element 15 based on the oxide film region 31 of the image data displayed on the screen 12.

In the inspection of the semiconductor element 15, since the inspection time is shorter than the energization time in the inspection unit 26, the transfer mechanism 27 in the Z direction and the transfer mechanism 28 in the X direction are used based on the determination result of the semiconductor element 15 after the inspection is completed. Alternatively, the non-defective product and the defective product of the semiconductor element 15 may be placed on the non-defective product tray, the defective product tray, or the like and transported. Similarly, using the transfer mechanism 27 in the Z direction and the transfer mechanism 28 in the X direction, the semiconductor element 15, the first intermediate material 18, the second intermediate material 17, and the third intermediate material 16 are respectively transferred to the transfer table. It may be carried by placing it on 3. As a result, the inspection time of the semiconductor element 15 can be shortened because the inspection is performed without human intervention.

Further, by mounting the imaging unit 22 on the base 1, the semiconductor element 15 is not required during the energization test without the need for a mechanism for inverting the semiconductor element 15 when inspecting the back surface 36 of the semiconductor element 15. Can be inspected.

Embodiment 2.
The semiconductor inspection apparatus according to the second embodiment of the present invention will be described with reference to FIG. In FIG. 8, the same reference numerals as those in FIG. 5 indicate the same or corresponding portions.

In the first embodiment, the second irradiation unit 24 is configured to irradiate the semiconductor element 15 from an oblique direction different from the light including the first wavelength. For example, the second irradiation unit 24 irradiates from the direction around the semiconductor element 15. It may be composed of an irradiation unit. FIG. 8 is a cross-sectional view of an inspection unit of the semiconductor inspection apparatus according to the second embodiment. By using the ring illumination 30 instead of the second irradiation unit 24, the semiconductor element 15 is irradiated from a wider range than the second irradiation unit 24.

With this configuration, the reflected light from the scratched area 32 becomes brighter than the irradiation light from the second irradiation unit 24. On the other hand, since the oxide film region 31 has a flat shape without unevenness, the reflected light from the oxide film region 31 is darker than the irradiation light from the second irradiation unit 24. As a result, high-contrast image data can be obtained by imaging, and the effect of improving the detection accuracy of these regions is achieved. Needless to say, as the illumination for irradiating the semiconductor element 15 from a wide range, an appropriately optimum illumination such as a dome illumination may be used instead of the ring illumination 30 according to the required irradiation range. ..

The above embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

1 base, 2 Y-direction transfer mechanism, 3 transport base, 4 current-carrying part, 5 cooling plate, 5a convex part, 6 probe, 7 pressure plate, 8 servo press, 9 columns, 10 power supply, 11 PLC, 12 screens, 13 Press controller, 14 power controller, 15 semiconductor element, 16 third interleaving material, 17 second interleaving material, 18 first interleaving material, 19 guide, 19a hole, 21 suction pad, 22 image pickup unit, 23 first Irradiation part, 24 second irradiation part, 25 shading wall, 26 inspection part, 27 Z direction transfer mechanism, 28 X direction transfer mechanism, 29 image processing part, 30 ring illumination, 31 oxide film area, 32 scratch area, 33 Normal region, 34 Gradation, 35 Front surface, 36 Back surface, 100 Semiconductor test equipment

Claims (6)

In a semiconductor inspection device that inspects whether or not there is discoloration due to an oxide film on the surface of a semiconductor element after energization.
An imaging unit provided at a position facing the surface and
A first irradiation unit provided between the surface and the imaging unit and irradiating the surface with light containing a first wavelength,
A second irradiation unit that irradiates the surface with light containing a second wavelength different from the first wavelength from a direction different from the light containing the first wavelength.
Image data by reflected light including the reflected light from the surface based on the first wavelength and the reflected light from the surface based on the second wavelength is acquired, and the contrast of the acquired image data is high. based at the semiconductor inspection device and an image processing unit to identify the oxide region is an image region that shows a color change due to the oxide film from among the image data. The semiconductor inspection apparatus according to claim 1, wherein the first wavelength is less than 380 nm. The semiconductor inspection apparatus according to claim 1, wherein the second wavelength is 380 nm or more and less than 780 nm. The semiconductor inspection apparatus according to any one of claims 1 to 3, wherein the spectral sensitivity characteristic of the imaging unit is such that the sensitivity of the second wavelength is higher than the sensitivity of the first wavelength. The semiconductor inspection apparatus according to any one of claims 1 to 4, wherein the image data is divided into at least two or more image regions including the oxide film region based on the height of contrast. It is a semiconductor inspection method that inspects whether or not the surface of a semiconductor element after energization is discolored by an oxide film.
From between the surface and the imaging unit, and a step of irradiating light including a first wavelength to said surface,
A step of irradiating the surface with light containing a second wavelength different from the first wavelength from a direction different from the light containing the first wavelength.
Image data by reflected light including the reflected light from the surface based on the first wavelength and the reflected light from the surface based on the second wavelength is acquired, and the contrast of the acquired image data is high. based at the semiconductor inspection method comprising a step of identifying the oxide region is an image region that shows a color change due to the oxide film from among the image data.

Images