Semiconductor element and solid-state imaging device

Abstract

The semiconductor element comprises: a plurality of microlenses disposed on a main surface for focusing light; a plurality of conductive electrodes disposed on a rear surface of the main surface; a photoelectric conversion portion for guiding light focused by the plurality of microlenses; and a strain sensor disposed on the same layer as the photoelectric conversion portion for detecting strain. The solid-state imaging device comprises: the aforementioned semiconductor element; a transparent member; an adhesive layer covering the plurality of microlenses and bonding the transparent member; and a plurality of external connection electrodes electrically connected to the plurality of conductive electrodes.

Description

Technical Field

[0001] The present disclosure relates to a semiconductor element and a solid-state imaging device. Background Art

[0002] In recent years, electronic components and electronic devices have been miniaturized, more highly functionalized, and more diverse. To meet these demands, semiconductor elements are being increasingly densely packed.

[0003] As a package for achieving high density semiconductor elements, for example, a wafer-level CSP (Chip Size Package) is generally known, in which a cover glass is attached to a semiconductor element via a film or an adhesive.

[0004] For example, Patent Document 1 discloses a semiconductor package. Figure 8 This is a cross-sectional view of the semiconductor package of Patent Document 1.

[0005] The semiconductor package 100 of Patent Document 1 comprises: a semiconductor element 102, wherein a circuit element is provided on a first surface 101a of a semiconductor substrate 101; an external wiring region 110, which is provided on a second surface 101b of the semiconductor substrate 101; a support substrate 104, wherein an adhesive layer 105 is provided on the first surface 101a of the semiconductor substrate 101, and comprises a light-transmitting material adhered and fixed by the adhesive layer 105; an electrode pad 106, which is arranged on the first surface 101a of the semiconductor substrate 101; and a through hole, which is opened in the semiconductor substrate 101 directly below the electrode pad 106, so that the electrode pad 106 can be seen from the semiconductor substrate. The second surface 101b of the plate 101 is exposed; the electrical insulating film 107 is configured to cover the second surface 101b of the semiconductor substrate 101 and the inner side surface of the through hole, exposing the electrode pad 106; the through electrode 108 is configured to cover the inner side surface of the through hole and the exposed portion of the electrode pad 106 via the electrical insulating film 107, and is electrically connected to the electrode pad 106; the external wiring 109 is used to connect the through electrode 108 and the external wiring area 110; the connecting portion is used to connect the external terminal to the external wiring area 110; and the protective film 113 covers all parts other than the connecting portion on the second surface 101b side of the semiconductor substrate 101.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 4722702 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] In the semiconductor package of Patent Document 1, mechanical stress, thermal stress, and the like in the assembly process of the package are concentrated on the adhesive layer that adheres and fixes the support substrate and the semiconductor substrate.

[0011] This stress concentration persists as strain even after the semiconductor package is completed. However, it is difficult to detect this strain as a defect during the electrical and optical inspections performed before shipment. Consequently, semiconductor packages with residual strain are shipped to customers as finished products. Subsequently, thermal stress generated during secondary mounting of the semiconductor package on a substrate and mechanical stress generated during module assembly can cause subsequent defects such as cracks and delamination at the interface of the adhesive layer or within semiconductor elements such as the multiple microlenses and color filters located beneath the adhesive layer.

[0012] An object of one embodiment of the present disclosure is to provide a semiconductor element and a solid-state imaging device capable of detecting a defect that may cause a subsequent defect before providing the defect to a user.

[0013] Means for solving problems

[0014] A semiconductor element according to one embodiment of the present disclosure includes: a plurality of microlenses disposed on a main surface for focusing light; a plurality of conductive electrodes disposed on the back surface of the main surface; a photoelectric conversion portion into which the light focused by the plurality of microlenses is introduced; and a strain sensor disposed on the same layer as the photoelectric conversion portion for detecting strain.

[0015] A solid-state imaging device according to one embodiment of the present disclosure includes: a semiconductor element according to one embodiment of the present disclosure; a transparent member; an adhesive layer covering the plurality of microlenses and bonding the transparent member; and a plurality of external connection electrodes electrically connected to the plurality of conductive electrodes.

[0016] Effects of the Invention

[0017] According to the present disclosure, a defect that may cause a subsequent defect can be detected before providing the information to the user. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a perspective view of the solid-state imaging device according to the first embodiment of the present disclosure.

[0019] Figure 2 It is a cross-sectional view of the solid-state imaging device according to the first embodiment of the present disclosure.

[0020] Figure 3 It is a cross-sectional view of the semiconductor element according to the first embodiment of the present disclosure.

[0021] Figure 4This is a flowchart of an inspection process of the solid-state imaging device according to the first embodiment of the present disclosure.

[0022] Figure 5 This is a table showing a comparison between a conventional inspection process and the inspection process according to the first embodiment of the present disclosure.

[0023] Figure 6 It is a top view of a semiconductor element according to Embodiment 2 of the present disclosure.

[0024] Figure 7 It is a top view of a semiconductor element according to Embodiment 3 of the present disclosure.

[0025] Figure 8 This is a cross-sectional view of the semiconductor package of Patent Document 1.

[0026] Explanation of symbols

[0027] 1 Transparent component

[0028] 2 Adhesive layer

[0029] 3 Semiconductor components

[0030] 4 External connection electrodes

[0031] 5 Microlenses

[0032] 6 Color Filters

[0033] 7 Photoelectric conversion unit

[0034] 8 Strain sensors

[0035] 8a p meter

[0036] 8b n meter

[0037] 9 Internal Wiring

[0038] 10 Conductive electrodes

[0039] 100 semiconductor packages

[0040] 100b Second side of semiconductor package

[0041] 101 Semiconductor Substrate

[0042] 101a: first surface of semiconductor substrate

[0043] 1O1b The second surface of the semiconductor substrate

[0044] 102 semiconductor components

[0045] 103 Circuit Elements

[0046] 104 Support base plate

[0047] 105 adhesive layer

[0048] 106 electrode pads

[0049] 106a Bottom surface of electrode pad

[0050] 107 Electrical insulating film

[0051] 108 through-electrode

[0052] 10gb The portion bonded to the electrode pad of the through-electrode

[0053] 109 External Wiring

[0054] 110 External wiring area

[0055] 111 Metal Rod

[0056] 113 protective film

[0057] 200 solid-state imaging device. DETAILED DESCRIPTION

[0058] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Components common to the various figures are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0059] The dimensions (e.g., thickness, length, etc.) of the components shown in the figures differ from their actual dimensions and are for ease of illustration. Furthermore, the number of microlenses, photoelectric conversion units, and external connection electrodes shown in the figures also differs from their actual numbers and is for ease of illustration. Furthermore, the materials used for the components are not limited to those described below.

[0060] [Implementation Method 1]

[0061] use Figure 1 、 Figure 2 、 Figure 3 The structure of the solid-state imaging device 200 according to this embodiment will be described. Figure 2 is a cross-sectional view of the solid-state imaging device 200 . Figure 3 1 is a cross-sectional view of the semiconductor element 3 provided in the solid-state imaging device 200 .

[0062] like Figure 1 、 Figure 2 As shown, the solid-state imaging device 200 includes a transparent member 1 , an adhesive layer 2 , a semiconductor element 3 , and a plurality of external connection electrodes 4 .

[0063] like Figure 3As shown, the semiconductor element 3 includes a plurality of microlenses 5 , a color filter 6 , a photoelectric conversion portion 7 , a strain sensor 8 , internal wiring 9 , and a plurality of conductive electrodes 10 .

[0064] like Figure 2 As shown, on the main surface of the semiconductor element 3 ( Figure 3 The color filter 6 shown in FIG. 1 is provided with a plurality of micro lenses 5. On the other hand, as shown in FIG. Figure 1 、 Figure 2 As shown in FIG. 1 , a plurality of conductive electrodes 10 are provided on the back side of the main surface of the semiconductor element 3. Figure 2 As shown, the plurality of conductive electrodes 10 are provided with a plurality of external connection electrodes 4 electrically connected to the plurality of conductive electrodes 10 .

[0065] like Figure 2 As shown, an adhesive layer 2 is provided on the main surface of the semiconductor element 3 so as to cover the entire microlenses 5. A transparent member 1 is provided on the adhesive layer 2 and is adhered and fixed thereto.

[0066] The material of the transparent member 1 may be, for example, a borosilicate glass plate, or a quartz plate or a low-pass filter having birefringence to prevent moire caused by interference fringes in a characteristic direction. When a borosilicate glass plate is used, the thickness of the transparent member 1 is, for example, in the range of 100 μm to 1000 μm, preferably in the range of 200 μm to 500 μm.

[0067] The adhesive layer 2 is an optically transparent mixture. Examples of materials for the adhesive layer 2 include acrylic resins, epoxy resins, and polyimide resins. Furthermore, the adhesive layer 2 is cured by ultraviolet irradiation, heating, or both, and has a lower refractive index than the plurality of microlenses 5.

[0068] like Figure 2 As shown, a plurality of external connection electrodes 4 are provided on the surfaces of the plurality of conductive electrodes 10 .

[0069] like Figure 3 As shown, the plurality of conductive electrodes 10 are electrically connected to the internal wiring 9 provided inside the semiconductor element 3. Thus, the solid-state imaging device 200 is secondarily mounted on a substrate (not shown; the same applies hereinafter) via the plurality of conductive electrodes 10 and the plurality of external connection electrodes 4, thereby electrically connecting the semiconductor element 3 to the substrate. The substrate is, for example, a circuit board of an electronic device.

[0070] The plurality of external connection electrodes 4 may be, for example, solder balls, conductive resin balls with a conductive coating formed on the surface, or bumps formed by wire bonding. Solder balls may be made of, for example, Sn-Ag-Cu, Sn-Ag-Bi, or Zn-Bi solder materials, but are not limited to these compositions.

[0071] Furthermore, when solder balls are used as the plurality of external connection electrodes 4, they can be bonded to the semiconductor element 3 by soldering. When conductive resin balls are used as the plurality of external connection electrodes 4, they can be bonded to the semiconductor element 3 by a conductive adhesive. Furthermore, for example, solder paste can be supplied to the plurality of external connection electrodes 4 using a screen printing method and then reflowed to form the plurality of external connection electrodes 4.

[0072] In addition, if Figure 3 As shown, a photoelectric conversion section 7 is provided inside the semiconductor element 3 below a plurality of microlenses 5 and a color filter 6. The photoelectric conversion section 7 is electrically connected to a plurality of conductive electrodes 10 via internal wiring 9. Light entering from the surface of the semiconductor element 3 is focused by the plurality of microlenses 5, filtered by the color filter 6, and then illuminates the photoelectric conversion section 7.

[0073] In addition, if Figure 3 As shown, a strain sensor 8 is provided inside the semiconductor element 3 below the color filter 6 and adjacent to the photoelectric conversion portion 7 .

[0074] The strain sensor 8 is a semiconductor formed by diffusing impurities such as phosphorus and boron into a silicon wafer, for example. The strain sensor 8 includes a p-gauge 8a and an n-gauge 8b.

[0075] The strain sensor 8 calculates strain based on the resistance change rate and the gauge factor, which are based on the voltage value measured when a constant current flows through the gauge and the change in voltage value measured when external stress is applied. Specifically, the strain sensor 8 detects strain using the piezoelectric resistance effect, whereby resistance changes when mechanical stress is applied to the gauge.

[0076] The strain sensor 8 is electrically connected to the plurality of conductive electrodes 10 via internal wiring 9. Thus, during the inspection process (strain inspection described later) of the solid-state imaging device 200, a constant current can flow from the outside of the semiconductor element 3 through the plurality of conductive electrodes 10 to the strain sensor 8, enabling voltage value measurement.

[0077] Furthermore, not only in the inspection process of the solid-state imaging device 200 but also in each process of manufacturing the solid-state imaging device 200 , a current can be passed from the outside of the semiconductor element 3 through the plurality of conductive electrodes 10 and a voltage can be measured.

[0078] Therefore, strain can be monitored in real time during a specific process. For example, during the bonding process of the transparent member 1, the following series of steps are involved: first, an adhesive is applied to form the bonding layer 2 on the plurality of microlenses 5; then, the transparent member 1 is mounted on the bonding layer 2; and finally, the bonding layer is cured using ultraviolet light and heat. By using the strain sensor 8, changes in resistance during this series of steps can be used to monitor strain changes. Furthermore, it is possible to determine which manufacturing process produces the greatest strain.

[0079] Therefore, by understanding the correlation between cracks and peeling phenomena that cause failures in the semiconductor element 3 and strain in advance, monitoring strain data in real time during manufacturing, and feeding the results back to manufacturing equipment, the solid-state imaging device 200 can be produced under appropriate manufacturing conditions.

[0080] In contrast, conventional inspection processes have included visual inspections to detect defects in transparent components, poor appearance of multiple conductive electrodes, electrical inspections (also known as continuity inspections) to detect poor conductivity and electrical characteristics, optical inspections to detect color unevenness and pixel flaws, image inspections to perform a sensory check of images actually captured by the solid-state imaging device, and dust inspections to detect foreign matter and dust on the surface of the transparent components. Afterward, the solid-state imaging device is packaged and shipped. Therefore, while pre-shipment defects can be detected, post-shipment defects (e.g., cracks and peeling) that may occur during post-shipment secondary mounting of the solid-state imaging device on a substrate or module assembly cannot be detected.

[0081] exist Figure 4 2 shows a flow of an inspection process of the solid-state imaging device 200 according to this embodiment. Figure 4 1 is a flowchart showing the flow of an inspection process of the solid-state imaging device 200 .

[0082] First, an appearance inspection is performed (step S1 ). In this appearance inspection, defects in the transparent member 1 and appearance defects in the plurality of conductive electrodes 10 are detected.

[0083] Next, an electrical inspection is performed (step S2 ). In this electrical inspection, detection of poor conduction, poor electrical characteristics, and the like is performed.

[0084] Next, an optical characteristic inspection is performed (step S3 ). In this optical characteristic inspection, color unevenness, pixel flaw defects, etc. are detected.

[0085] Next, an image inspection is performed (step S4 ). In this image inspection, a sensory inspection is performed on the image actually captured by the solid-state imaging device 200 .

[0086] Next, a strain inspection is performed (step S5 ). In this strain inspection, strain is detected using the strain sensor 8 (specifically, residual stress inside the semiconductor element 3 is measured).

[0087] Finally, a dust inspection is performed (step S6 ). In this dust inspection, foreign matter and dust on the surface of the transparent member 1 are detected.

[0088] The solid-state imaging device 200 that has undergone the inspections in steps S1 to S6 is packaged and shipped.

[0089] As described above, the inspection process of the solid-state imaging device 200 is different from the conventional inspection process in that the strain inspection of step S5 is added.

[0090] exist Figure 5 A comparison between the conventional inspection process and the inspection process of this embodiment is shown in FIG. Figure 5 In the figure, a circle mark indicates that a bad item can be detected, and a cross mark indicates that a bad item cannot be detected.

[0091] In the inspection process of this embodiment, products that may have late-generation defects such as late-generation image defects and late-generation image strain can be detected.

[0092] The aforementioned latent image defects refer to scratches on pixels caused by the peeling of microlenses, color filters, or adhesive layers due to stress in post-shipment processes (e.g., secondary assembly or module assembly). Furthermore, the aforementioned latent image strain refers to image strain caused by strain in the microlenses or adhesive layers themselves due to stress in post-shipment processes.

[0093] Figure 5 The characteristics shown (after-emission) are the reduction of light sensitivity, spectral characteristics, etc. In addition, Figure 5 The image (afterimage) shown is a general term including the above-mentioned afterimage defects and afterimage strain.

[0094] Typically, residual stress before shipment and stress generated during post-shipment processes cause the aforementioned peeling and strain, leading to the aforementioned subsequent defects. In contrast, the inspection process of this embodiment can detect residual stress within the semiconductor element 3 before shipment. Therefore, by investigating the correlation (the same relationship) between residual stress before shipment and stress generated during post-shipment processes and the occurrence of subsequent defects, and by detecting residual stress before shipment during the process of this embodiment, it is possible to detect products that are likely to have subsequent defects.

[0095] [Implementation Method 2]

[0096] use Figure 6The structure of the semiconductor element 3 according to this embodiment will be described. Figure 6 This is a plan view of the semiconductor element 3 according to the present embodiment as viewed from the transparent member 1 side (in other words, the main surface side).

[0097] like Figure 6 As shown, a plurality of microlenses 5 are arranged in a grid pattern on the main surface of the semiconductor element 3. A photoelectric conversion unit 7 is provided directly below each microlens 5. As a result, the paths of light entering the plurality of microlenses 5 from the outside are changed by the plurality of microlenses 5, and more light is collected by the photoelectric conversion unit 7.

[0098] Here, in order to improve the sensitivity characteristics of the solid-state imaging device, it is important that light entering from the plurality of microlenses 5 is not blocked and reaches the photoelectric conversion unit 7. Therefore, the strain sensor 8 needs to be provided at a position that does not affect the light travel path.

[0099] The strain detected by strain sensor 8 is primarily caused by mechanical or thermal stress in adhesive layer 2, which covers each microlens 5 and adheres and secures transparent member 1. Therefore, defects primarily occur at the interface between adhesive layer 2 and the microlenses 5, or at the interface between the microlenses 5 and the underlying color filter 6.

[0100] Furthermore, the plurality of microlenses 5 are often formed of a low-elastic material that easily absorbs stress. Therefore, the stress is likely to concentrate between the plurality of adjacent microlenses 5 .

[0101] From the viewpoint of the light path and stress concentration described above, in the semiconductor element 3 of this embodiment, Figure 6 As shown, when looking down at the semiconductor element 3 from the side of the transparent component 1, a strain sensor 8 is arranged directly below the boundary portion of the adjacent multiple microlenses 5 (it can also be said that the contact portion between the adjacent multiple microlenses 5) and between the adjacent photoelectric conversion parts 7 (hereinafter referred to as between the photoelectric conversion parts).

[0102] In addition, Figure 6 In the figure, strain sensors 8 are shown as an example, arranged between all photoelectric conversion parts. However, the present invention is not limited to this. For example, strain sensors 8 may be arranged only between photoelectric conversion parts that are expected to be particularly susceptible to stress. Alternatively, if it is desired to determine the strain tendency of the entire semiconductor element 3, strain sensors 8 may be arranged only between photoelectric conversion parts located in the center of the main surface of the semiconductor element 3 and between photoelectric conversion parts located on the outer periphery or corners of the main surface of the semiconductor element 3.

[0103] As above Figure 6 The semiconductor element 3 is provided at Figure 1 、 Figure 2The solid-state imaging device 200 is shown.

[0104] [Implementation Method 3]

[0105] use Figure 7 , the structure of the semiconductor element 3 of this embodiment is described. Figure 7 This is a plan view of the semiconductor element 3 according to the present embodiment as viewed from the transparent member 1 side (in other words, the main surface side).

[0106] like Figure 7 As shown, the arrangement positions of the plurality of micro lenses 5 and the photoelectric conversion unit 7 are similar to those of FIG. Figure 6 That is, a plurality of microlenses 5 are arranged in a lattice pattern on the main surface of the semiconductor element 3 , and a photoelectric conversion unit 7 is provided directly below each microlens 5 .

[0107] like Figure 7 As shown, when the semiconductor element 3 is viewed from the transparent member 1 side, the multiple microlenses 5 are circular in shape. Furthermore, when the semiconductor element 3 is viewed from above from the transparent member 1 side, stress tends to concentrate in the area surrounded by the outer edges of four adjacent microlenses 5. This area can also be referred to as an area where the multiple microlenses 5 are not arranged, and is therefore hereinafter referred to as a "microlens non-arrangement area."

[0108] From the perspective of the above-mentioned stress concentration, in the semiconductor element 3 of this embodiment, a strain sensor 8 is arranged directly below the microlens non-configuration area (more specifically, directly below the central portion of the multiple microlens non-configuration areas) and between the photoelectric conversion parts 7 adjacent in the oblique direction.

[0109] In addition, Figure 7 In the figure, as an example, the strain sensors 8 are shown as being arranged in all of the multiple microlens non-configuration areas, but the present invention is not limited to this. For example, the strain sensors 8 may be arranged only in the microlens non-configuration areas that are assumed to be particularly susceptible to stress. Alternatively, for example, the strain sensors 8 may be arranged only in the multiple microlens non-configuration areas located in the center of the main surface of the semiconductor element 3 and the multiple microlens non-configuration areas located on the peripheral side or corner side of the main surface of the semiconductor element 3. Alternatively, for example, the strain sensors 8 may be arranged at equal intervals throughout the area where the multiple microlenses 5 are arranged. Furthermore, for example, when it is desired to measure strain for development purposes, it is also possible to randomly select multiple microlens non-configuration areas to be measured and arrange the strain sensors 8 only in these multiple microlens non-configuration areas.

[0110] As above Figure 7 The semiconductor element 3 is provided at Figure 1 、 Figure 2 The solid-state imaging device 200 is shown.

[0111] As described above, the semiconductor element 3 of this embodiment is characterized in that it has: a plurality of microlenses 5, which are arranged on the main surface to focus light; a plurality of conductive electrodes 10, which are arranged on the back side of the main surface; a photoelectric conversion part 7, into which the light focused by the plurality of microlenses 5 is introduced; and a strain sensor 8, which is arranged on the same layer as the photoelectric conversion part 7 to detect strain.

[0112] In addition, the solid-state imaging device 200 of this embodiment is characterized in that it has: the semiconductor element 3 of the above-mentioned embodiment; a transparent component 1; an adhesive layer 2 covering multiple microlenses 5 and bonding the transparent component 1; and multiple external connection electrodes 4, which are electrically connected to multiple conductive electrodes 10 respectively.

[0113] Due to the above features, the semiconductor element 3 and the solid-state imaging device 200 of this embodiment can detect defects (strains) that may cause subsequent defects (occurring in a secondary mounting process or a module assembly process) before providing them to users.

[0114] In addition, the present disclosure is not limited to the description of the above-mentioned embodiment, and various modifications can be made without departing from the scope of the present disclosure.

[0115] Industrial applicability

[0116] The semiconductor element and solid-state imaging device disclosed herein can pre-detect defects that may occur after the device is provided to the user and that could not be detected in conventional inspection processes. This is useful in semiconductor elements and solid-state imaging devices that are becoming increasingly miniaturized and highly functional.

Claims

1. A semiconductor device comprising: A plurality of micro lenses are provided on the main surface to focus the light; a plurality of conductive electrodes disposed on the back side of the main surface; a photoelectric conversion portion to which the light focused by the plurality of microlenses is introduced; as well as The strain sensor is provided in the same layer as the photoelectric conversion unit, detects strain using a piezoresistive effect in which resistance changes when mechanical stress is applied to a gauge, and is electrically connected to the plurality of conductive electrodes via internal wiring.

2. The semiconductor element according to claim 1, wherein The photoelectric conversion unit is provided corresponding to each position of the plurality of micro lenses. The strain sensor is arranged between adjacent photoelectric conversion parts.

3. The semiconductor element according to claim 2, wherein When the semiconductor element is viewed from above from the main surface side, The plurality of micro lenses are arranged in a grid pattern, The strain sensor is arranged directly below a boundary portion between adjacent microlenses.

4. The semiconductor element according to claim 2, wherein When the semiconductor element is viewed from above from the main surface side, The plurality of micro lenses are arranged in a grid pattern, The strain sensor is arranged directly below a region where the plurality of microlenses are not arranged.

5. The semiconductor element according to claim 1 or 2, wherein The semiconductor element further includes a color filter provided between the plurality of microlenses and the photoelectric conversion unit, and filtering the light focused by the plurality of microlenses.

6. A solid-state imaging device comprising: The semiconductor element according to claim 1 or 2; Transparent components; an adhesive layer covering the plurality of microlenses and bonding the transparent member; and A plurality of external connection electrodes are electrically connected to the plurality of conductive electrodes respectively.

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