Method for manufacturing semiconductor device, and semiconductor device

Abstract

The purpose of the present invention is to provide a technique with which it is possible to suppress erroneous determination in automatic determination of inspection by reducing noise in an image used when determining a bonding state between a semiconductor element and an electroconductive pattern. A method for manufacturing a semiconductor device according to the present invention comprises: a step (A) for bonding a semiconductor element to an electroconductive pattern on an insulating substrate via solder; a step (B) for bonding a lead electrode to the upper surface of the semiconductor element; a step (C) for capturing an image of an inspection target layer composed of solder present directly below the semiconductor element, and an image of a neighboring layer having a depth in the vicinity of the image of the inspection target layer; a step (D) for generating a noise reduction image by superimposing the image of the inspection target layer and the image of the neighboring layer; and a step (E) for determining the bonding state between the semiconductor element and the electroconductive pattern on the basis of the noise reduction image.

Description

Semiconductor device manufacturing method and semiconductor inspection device

[0001] The present disclosure relates to a method for manufacturing a semiconductor device and a semiconductor inspection device.

[0002] 2. Description of the Related Art Conventionally, inspections using X-ray images have been carried out to non-destructively inspect the quality of the soldering of electronic components such as semiconductor elements soldered to conductive patterns on insulating substrates.

[0003] For example, Patent Document 1 discloses a method for accurately setting an inspection area on an object to be inspected when inspecting the object using an X-ray image.

[0004] JP 2012-237729 A

[0005] Conventional inspection methods involve the steps of joining a semiconductor element to a conductive pattern on an insulating substrate via solder, joining lead electrodes to the top surface of the semiconductor element, and taking transmission images to determine the bonding condition between the semiconductor element and the conductive pattern. Transmission images are prone to noise due to their inherent characteristics, which reduces the visibility of the bonding condition between the semiconductor element and the conductive pattern, leading to erroneous determinations in automated inspections.

[0006] Therefore, the present disclosure aims to provide a technology that can suppress erroneous judgments in automatic inspection judgments by reducing noise in images used when determining the bonding state between a semiconductor element and a conductive pattern.

[0007] The method for manufacturing a semiconductor device according to the present disclosure includes the steps of: (A) joining a semiconductor element to a conductive pattern on an insulating substrate via solder; (B) joining lead electrodes to the top surface of the semiconductor element; (C) capturing an image of the inspection target layer, which is the solder located directly below the semiconductor element, and an image of a nearby layer, which is a layer at a similar depth; (D) superimposing the image of the inspection target layer and the image of the nearby layer to generate an image with reduced noise; and (E) determining the bonding condition between the semiconductor element and the conductive pattern based on the noise-reduced image.

[0008] According to the present disclosure, noise in images used when determining the bonding state between a semiconductor element and a conductive pattern is reduced, making it possible to suppress erroneous determinations in automatic inspections.

[0009] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0010] Fig. 1 is a block diagram showing a configuration of a semiconductor inspection device according to a first embodiment; Fig. 2 is a cross-sectional view of a semiconductor device that is an inspection target of the semiconductor inspection device according to the first embodiment; Fig. 3 is a diagram for explaining an image capturing step in the first embodiment; Fig. 4 is a flowchart for explaining an inspection method included in a semiconductor device manufacturing method according to the first embodiment; Fig. 4 is a diagram for explaining a transmission image capturing step in a second embodiment; Fig. 5 is a flowchart for explaining an inspection method included in a semiconductor device manufacturing method according to the second embodiment; Fig. 5 is a flowchart for explaining an inspection method included in a semiconductor device manufacturing method according to a third embodiment.

[0011] <First Embodiment> A first embodiment will be described below with reference to the drawings. Fig. 1 is a block diagram showing the configuration of a semiconductor inspection device 100 according to the first embodiment. Fig. 2 is a cross-sectional view of a semiconductor device 10 that is an object of inspection by the semiconductor inspection device 100 according to the first embodiment. Fig. 3 is a diagram for explaining the image pickup process in the first embodiment.

[0012] 1, the semiconductor inspection device 100 is a device that non-destructively inspects the quality of the soldered joint state of a semiconductor device 10 (see FIG. 2). The semiconductor inspection device 100 includes an image capturing device 30, an image processing device 40, and an image evaluation device 50.

[0013] First, the structure of the semiconductor device 10 to be inspected by the semiconductor inspection equipment 100 will be described.

[0014] As shown in Figure 2, the semiconductor device 10 includes an insulating substrate 1, a semiconductor element 3, lead electrodes 4, a resin case 5, and heat dissipation fins 6. The insulating substrate 1, which has a conductive pattern 2 on its upper surface, is provided on the inner periphery of the upper surface of the heat dissipation fins 6. The semiconductor element 3 is bonded onto the conductive pattern 2 via solder 7. The lead electrodes 4 are bonded to the upper surface of the semiconductor element 3. A frame-shaped resin case 5 is fixed to the outer periphery of the upper surface of the heat dissipation fins 6 so as to surround the side surfaces of the insulating substrate 1 and the semiconductor element 3. The resin case 5 is filled with a sealing resin 9 that seals the semiconductor element 3.

[0015] Returning to the description of the semiconductor inspection device 100, as shown in Fig. 1, the image capturing device 30 captures an image of the inspection target layer and an image of a nearby layer. In the first embodiment, the image capturing device 30 simultaneously captures the image of the inspection target layer and the image of the nearby layer.

[0016] As shown in FIG. 3 , the image of the inspection target layer and the image of the nearby layer are images captured from the horizontal direction of the semiconductor device 10. The inspection target layer is the layer of solder 7 located between the conductive pattern 2 and the semiconductor element 3, i.e., directly below the semiconductor element 3. The nearby layer is a layer at a nearby depth of the inspection target layer, specifically, a portion located above the solder 7. More specifically, the nearby layer is a layer located at any depth within the range from the semiconductor element 3 to the upper side of the lead electrode 4 bonded to the upper surface of the semiconductor element 3. In other words, the nearby layer may be a layer of the semiconductor element 3, or may be a layer stack ranging from the semiconductor element 3 to the upper side of the lead electrode 4 bonded to the upper surface of the semiconductor element 3. The image capturing device 30 is, for example, a camera, more specifically, an X-ray camera.

[0017] 1, the image processing device 40 generates an image with reduced noise by superimposing an image of the inspection target layer and an image of a neighboring layer. The image processing device 40 is, for example, an image processor.

[0018] The image assessment device 50 assesses the bonding state between the semiconductor element 3 and the conductive pattern 22 based on the noise-reduced image. The image assessment device 50 is, for example, a processor.

[0019] <Manufacturing Method> Next, a manufacturing method of the semiconductor device 10 will be described with reference to Fig. 4. Fig. 4 is a flowchart for explaining an inspection method included in the manufacturing method of the semiconductor device 10 according to the first embodiment.

[0020] Although not shown, first, a semiconductor element 3 is bonded to a conductive pattern 2 on an insulating substrate 1 via solder 7, and then lead electrodes 4 are bonded to the upper surface of the semiconductor element 3 to produce an assembly. Next, the assembly is fixed in a resin case 5 fixed to heat dissipation fins 6, and then the resin case 5 is filled with sealing resin 9. Through the above steps, a semiconductor device 10 is produced.

[0021] Next, the semiconductor device 10 is placed on an inspection stage (not shown), and an image of the inspection target layer and an image of a nearby layer are captured by the image capturing device 30 (step S1). As described above, in the first embodiment, the image of the inspection target layer and the image of the nearby layer are captured simultaneously.

[0022] After capturing the images, the captured images are transferred from the image capturing device 30 to the image processing device 40 (step S2). The transferred images are superimposed in the image processing device 40 to generate a noise-reduced image, which is an image with reduced noise (step S3). Note that a well-known method is used for the image superimposition process.

[0023] After the noise-reduced image is generated, the noise-reduced image is transferred from the image processing device 40 to the image assessment device 50 (step S4). The image assessment device 50 determines whether the bonding state between the semiconductor element 3 and the conductive pattern 2 is good or bad based on the transferred image (step S5). Through the above steps, the manufacture of the semiconductor device 10 is completed.

[0024] <Effects> As described above, the manufacturing method of semiconductor device 10 according to the first embodiment includes the steps of: (A) joining semiconductor element 3 to conductive pattern 2 on insulating substrate 1 via solder 7; (B) joining lead electrodes 4 to the upper surface of semiconductor element 3; (C) capturing an image of the inspection target layer, which is solder 7 located directly below semiconductor element 3, and an image of a nearby layer, which is a layer at a nearby depth; (D) superimposing the image of the inspection target layer and the image of the nearby layer to generate a noise-reduced image; and (E) determining the bonding state between semiconductor element 3 and conductive pattern 2 based on the noise-reduced image. Specifically, the image of the nearby layer is a layered image of a portion located above solder 7.

[0025] Therefore, noise in the image used when determining the bonding state between the semiconductor element 3 and the conductive pattern 2 is reduced, making it possible to suppress erroneous determinations in automatic determinations.

[0026] Furthermore, in step (C), an image of the inspection target layer and an image of the adjacent layer are captured simultaneously, so that an increase in the time required for inspection can be suppressed.

[0027] Second Preferred Embodiment Next, a method for manufacturing the semiconductor device 10 according to a second preferred embodiment will be described. Fig. 5 is a diagram for explaining the process of capturing a transmitted image in the second preferred embodiment. Note that in the second preferred embodiment, the same components as those described in the first preferred embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0028] <Configuration> In the first embodiment, the object was to reduce noise in the image used when determining the bonding state between the semiconductor element 3 and the conductive pattern 2. However, in the second embodiment, in order to further identify the layer in which a defect has occurred, the image capturing device 30 captures a transmission image in the vertical direction (the direction of the dotted line in FIG. 5 ) of the portion of the semiconductor device 10 including the layer to be inspected, in addition to capturing an image of the inspection target layer and images of nearby layers as in the first embodiment. The transmission image is an image captured from above the semiconductor device 10. The portion of the semiconductor device 10 including the layer to be inspected is, in other words, a portion including the solder 7 located directly below the semiconductor element 3, and is the range indicated by the arrow in FIG. 5 .

[0029] <Manufacturing Method> Next, a manufacturing method of the semiconductor device 10 will be described with reference to Fig. 6. Fig. 6 is a flowchart for explaining an inspection method included in the manufacturing method of the semiconductor device 10 according to the second embodiment.

[0030] As in the first embodiment, first, the semiconductor device 10 is fabricated. Next, the semiconductor device 10 is placed on an inspection stage (not shown), and an image of the inspection target layer and an image of a nearby layer are captured by the image capturing device 30 (step S1). In the second embodiment, the image of the inspection target layer and the image of the nearby layer are captured simultaneously.

[0031] Next, the image capturing device 30 captures a vertical transmission image (step S11). After capturing the image, the captured image is transferred from the image capturing device 30 to the image processing device 40 (step S2). The image processing device 40 overlays the transferred images to generate a noise-reduced image, which is an image with reduced noise (step S3). More specifically, the image processing device 40 performs overlay processing on the image of the inspection target layer and the image of the adjacent layer.

[0032] After the noise-reduced image is generated, the noise-reduced image and the vertical transmission images are transferred from the image processing device 40 to the image assessment device 50 (step S41). The image assessment device 50 determines whether the bonding state between the semiconductor element 3 and the conductive pattern 2 is good or bad based on the transferred images (step S5). More specifically, the image assessment device 50 determines whether the bonding state between the semiconductor element 3 and the conductive pattern 2 is good or bad based on the noise-reduced image, and if it determines that the bonding state is poor, it uses the vertical transmission images to identify the layer in which the defect occurred.

[0033] <Effects> As described above, in the manufacturing method of the semiconductor device 10 according to the second embodiment, in step (C), a vertical transmission image of the portion of the semiconductor device 10 including the layer to be inspected is further captured, and in step (E), the transmission image is further used when it is determined that the bonding state between the semiconductor element 3 and the conductive pattern 2 is poor.

[0034] Therefore, in addition to the effect of the first embodiment, when it is determined that the bonding state is poor, it is possible to identify the layer in which the defect occurs.

[0035] Third Preferred Embodiment Next, a method for manufacturing the semiconductor device 10 according to a third preferred embodiment will be described. In the third preferred embodiment, the same components as those described in the first and second preferred embodiments will be denoted by the same reference numerals, and the description thereof will be omitted.

[0036] <Configuration> In embodiment 1, the image capturing device 30 captured an image of the layer to be inspected and an image of a nearby layer simultaneously, but in embodiment 3, the image capturing device 30 captures an image of the layer to be inspected and an image of a nearby layer at different times.

[0037] <Manufacturing Method> Next, a manufacturing method of the semiconductor device 10 will be described with reference to Fig. 7. Fig. 7 is a flowchart for explaining an inspection method included in the manufacturing method of the semiconductor device 10 according to the third embodiment.

[0038] As in the first embodiment, first, the semiconductor device 10 is fabricated. Next, the semiconductor device 10 is placed on an inspection stage (not shown), and an image of the inspection target layer is captured by the image capturing device 30 (step S12). Next, an image of a nearby layer is captured by the image capturing device 30 (step S13). After capturing the image, the captured image is transferred from the image capturing device 30 to the image processing device 40 (step S2). Since the subsequent steps are the same as those in the first embodiment, a description thereof will be omitted.

[0039] The order of steps S12 and S13 may be changed, and an image of the inspection target layer may be captured after an image of the nearby layer is captured by the image capturing device 30. In addition, in the second embodiment, the image capturing device 30 may capture the image of the inspection target layer and the image of the nearby layer at different times.

[0040] <Effects> As described above, in the manufacturing method of the semiconductor device 10 according to the third embodiment, in step (C), the image of the inspection target layer and the image of the neighboring layer are captured at different times. Therefore, the image of the inspection target layer and the image of the neighboring layer can be captured under different conditions, making it possible to set specialized conditions for each of the images. This makes it possible to acquire images with less noise.

[0041] Although this disclosure has been described in detail, the above description is illustrative in all respects and is not restrictive. It is understood that countless variations not illustrated can be envisioned.

[0042] It should be noted that the embodiments can be freely combined, and each embodiment can be modified or omitted as appropriate.

[0043] REFERENCE SIGNS LIST 1 insulating substrate, 2 conductive pattern, 3 semiconductor element, 4 lead electrode, 7 solder, 10 semiconductor device, 30 image capturing device, 40 image processing device, 50 image evaluation device, 100 semiconductor inspection device

Claims

1. A method for manufacturing a semiconductor device, comprising: (A) joining a semiconductor element to a conductive pattern on an insulating substrate via solder; (B) joining lead electrodes to the top surface of the semiconductor element; (C) capturing an image of the inspection target layer, which is the solder located directly below the semiconductor element, and an image of a nearby layer, which is a layer at a similar depth; (D) superimposing the image of the inspection target layer and the image of the nearby layer to generate an image with reduced noise; and (E) determining the bonding condition between the semiconductor element and the conductive pattern based on the noise-reduced image.

2. The method for manufacturing a semiconductor device according to claim 1, wherein the image of the adjacent layer is a stacked image of a portion located above the solder.

3. The method for manufacturing a semiconductor device according to claim 1, wherein in step (C), a vertical transmission image of a portion of the semiconductor device including the layer to be inspected is further captured, and in step (E), the transmission image is further used if it is determined that the bonding state between the semiconductor element and the conductive pattern is poor.

4. A method for manufacturing a semiconductor device according to claim 2, wherein in step (C), a vertical transmission image of a portion of the semiconductor device including the layer to be inspected is further captured, and in step (E), the transmission image is further used if it is determined that the bonding state between the semiconductor element and the conductive pattern is poor.

5. A method for manufacturing a semiconductor device according to any one of claims 1 to 4, wherein in step (C), an image of the inspection target layer and an image of the adjacent layer are captured simultaneously.

6. A method for manufacturing a semiconductor device according to any one of claims 1 to 4, wherein in step (C), the image of the inspection target layer and the image of the adjacent layer are captured at different times.

7. A semiconductor inspection device for inspecting a semiconductor device having an insulating substrate having a conductive pattern on its upper surface, a semiconductor element bonded to the conductive pattern on the insulating substrate via solder, and lead electrodes bonded to the upper surface of the semiconductor element, comprising: an image capturing device that captures an image of the inspection target layer, which is the solder located directly below the semiconductor element, and an image of a nearby layer, which is a layer at a nearby depth; an image processing device that overlays the image of the inspection target layer and the image of the nearby layer to generate an image with reduced noise; and an image assessment device that assesses the bonding state of the semiconductor element and the conductive pattern based on the noise-reduced image.

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