Distance measurement device

Abstract

A distance measurement device according to the present disclosure comprises a circuit board, a light emission unit, first and second connection units, first and second side wall units, a light receiving unit, a transparent member, and a reflection member. The light emission unit is disposed on the main surface of the circuit board. The first connection unit includes a porous metal layer and electrically connects the light emission unit and the circuit board. The first side wall unit includes a porous metal layer and is provided between the light emission unit and the circuit board so as to surround the first connection unit. The light receiving unit is disposed on the main surface of the circuit board and receives light emitted by the light emission unit. The second connection unit includes a porous metal layer and electrically connects the light receiving unit and the circuit board. The second side wall unit includes a porous metal layer and is provided between the light receiving unit and the circuit board so as to surround the second connection unit. The transparent member is provided between the light emission unit and the light receiving unit and on the main surface of the circuit board. The reflection member is provided to the transparent member and guides some of the light emitted by the light emission unit to part of the region of the light receiving unit.

Description

distance measuring device

[0001] The present disclosure relates to a distance measuring device.

[0002] One of the distance measurement methods is the Time-of-Flight (hereinafter referred to as ToF) method. A distance measurement device using the ToF method measures the distance to an object by emitting light and receiving the light that hits the object and is reflected back.

[0003] For example, there is a technology in which a distance measuring device directly receives emitted light to generate a reference signal to be used for distance measurement, and measures the distance to an object using this reference signal.

[0004] International Publication No. 2017 / 209206

[0005] A ToF distance measuring device includes, for example, a light emitting unit and a light receiving unit. For example, the light receiving unit instructs the light emitting unit to emit light and starts measuring time. The light receiving unit stops measuring time when it receives reflected light from the target. The light receiving unit measures the distance to the target based on the measured time.

[0006] There is a time lag (delay) between when the light receiving unit starts measuring time and when the light emitting unit emits light. In order for a distance measuring device to measure distances with higher accuracy, it is desirable to reduce the effect of this delay.

[0007] Therefore, the present disclosure proposes a distance measuring device that can further reduce the effect of delay.

[0008] It should be noted that the above problem or object is merely one of multiple problems or objects that can be solved or achieved by multiple embodiments disclosed in this specification.

[0009] The distance measuring device disclosed herein includes a circuit board, a light emitting unit, a first connection unit, a first side wall unit, a light receiving unit, a second connection unit, a second side wall unit, a transparent member, and a reflective member. The light emitting unit is disposed on a main surface of the circuit board. The first connection unit includes a porous metal layer and electrically connects the light emitting unit and the circuit board. The first side wall unit includes a porous metal layer and is provided between the light emitting unit and the circuit board so as to surround the first connection unit. The light receiving unit is disposed on the main surface of the circuit board and receives light emitted by the light emitting unit. The second connection unit includes a porous metal layer and electrically connects the light receiving unit and the circuit board. The second side wall unit includes a porous metal layer and is provided between the light receiving unit and the circuit board so as to surround the second connection unit. A transparent member is provided on the main surface of the circuit board between the light emitting unit and the light receiving unit. The reflecting member is provided on the transparent member and guides a portion of the light emitted by the light emitting portion to a partial area of ​​the light receiving portion.

[0010] 12 is a block diagram showing a schematic configuration example of an information processing system according to a first embodiment of the present disclosure. FIG. 13 is a cross-sectional explanatory diagram of a distance measuring device according to the first embodiment of the present disclosure. FIG. 14 is a top view of a distance measuring device according to the first embodiment of the present disclosure. FIG. 15 is a cross-sectional explanatory diagram taken along line A-A shown in FIG. 2. FIG. 16 is a diagram showing an example of distance measurement by the distance measuring device according to the first embodiment of the present disclosure. FIG. 17 is an explanatory diagram showing a process of forming sidewall portions and connection portions on a semiconductor substrate according to the present disclosure. FIG. 18 is an explanatory diagram showing a process of forming sidewall portions and connection portions on a semiconductor substrate according to the present disclosure. FIG. 19 is an explanatory diagram showing a process of forming sidewall portions and connection portions on a semiconductor substrate according to the present disclosure. FIG. 19 is an explanatory diagram showing a cross-sectional view of a distance measuring device according to a first modified example of the first embodiment of the present disclosure. FIG. 20 is a cross-sectional view of a distance measuring device according to a second modified example of the first embodiment of the present disclosure. FIG. 21 is a cross-sectional explanatory diagram taken along line B-B shown in FIG. 2. FIG. 22 is an explanatory diagram showing a process of forming connection portions on a semiconductor substrate according to the second embodiment of the present disclosure. Fig. 10 is an explanatory diagram showing a process of forming a connection portion on a semiconductor substrate according to a second embodiment of the present disclosure; Fig. 11 is an explanatory diagram showing a process of forming a connection portion on a semiconductor substrate according to a second embodiment of the present disclosure; Fig. 12 is a diagram showing a cross-sectional view of a distance measuring device according to a first modified example of the second embodiment of the present disclosure; Fig. 13 is a diagram showing a cross-sectional view of a distance measuring device according to a second modified example of the second embodiment of the present disclosure.

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following embodiments, the same components are designated by the same reference numerals and / or the same hatching, and redundant description will be omitted.

[0012] The various conditions in this specification are satisfied not only when they are strictly met, but also when they are substantially met. Various variations that occur in design or manufacturing are allowed. Furthermore, the drawings used in the following description are schematic and do not represent actual dimensions or proportions.

[0013] <<1. First embodiment>> <1.1. Configuration example of information processing system 1> First, a first embodiment of the present disclosure will be described in detail with reference to the drawings.

[0014] 1 is a block diagram showing a schematic configuration example of an information processing system 1 according to a first embodiment of the present disclosure. The information processing system 1 according to this embodiment executes an application using, for example, a distance measurement result of an object. Examples of the information processing system 1 include various electronic devices such as mobile terminals such as smartphones, tablet terminals, and mobile phones, as well as cameras and sensor devices.

[0015] The information processing system 1 shown in FIG. 1 includes a distance measuring device 100, an arithmetic processing unit 20, and an application processor 30.

[0016] The distance measuring device 100 measures the distance to an object present around the information processing system 1. The distance measuring device 100 includes an imaging device 10, a light emission control unit 14 (an example of a drive circuit), and a light emitting unit 15.

[0017] The imaging device 10 includes a lens 11, an imaging unit 12, and a signal processing unit 13. A light-emitting system including a light-emitting unit 15 and a light-emitting control unit 14 is connected to the imaging device 10.

[0018] The light-emitting unit 15 outputs irradiation light (e.g., laser light) under the control of the light-emitting control unit 14. An example of the light-emitting unit 15 is a vertical cavity surface emitting laser (VCSEL) that emits laser light as a surface light source. Note that the light-emitting unit 15 is not limited to a VCSEL, and may be, for example, an edge-emitting laser.

[0019] When a control signal instructing light emission is input from the signal processing unit 13, the light emission control unit 14 causes the light emitting unit 15 to emit light.

[0020] Here, the distance measuring device 100 is a direct ToF (dToF) type sensor that calculates the distance to an object based on the elapsed time from when the light emitting unit 15 emits light to when the imaging unit 12 detects reflected light.

[0021] The imaging device 10 receives light (reflected light) that is emitted from the light-emitting unit 15 and reflected by an object (target of distance measurement). The imaging device 10 also receives the illumination light emitted from the light-emitting unit 15. The imaging device 10 generates a reference signal based on the illumination light that is received by the imaging device 10 without being reflected by the target of distance measurement. The imaging device 10 measures the distance to the object based on the reference signal and the reflected light.

[0022] The signal processing unit 13 performs various signal processing on the raw data output from the imaging unit 12. For example, the signal processing unit 13 calculates the distance (depth value) from the imaging device 10 to an object based on the raw data (pixel data) supplied from the imaging unit 12. The signal processing unit 13 generates a depth map (also referred to as a depth image or ranging image) in which depth values ​​(depth information) are stored as pixel values ​​of each pixel of the imaging unit 12, and outputs the depth map to the arithmetic processing unit 20. At this time, the signal processing unit 13 may also calculate the reliability of the calculated depth value for each pixel of the imaging unit 12, and generate a reliability map in which reliability (luminance information) is stored as pixel values ​​of each pixel of the imaging unit 12, and output the reliability map to the arithmetic processing unit 20.

[0023] The imaging device 10 may be configured such that the imaging unit 12 and the signal processing unit 13 are arranged on different semiconductor chips, or may be configured such that they are arranged on a single semiconductor chip. Furthermore, the single semiconductor chip on which the imaging unit 12 and the signal processing unit 13 are arranged may be a laminated chip in which a semiconductor chip on which the imaging unit 12 is arranged and a semiconductor chip on which the signal processing unit 13 is arranged are bonded together.

[0024] Furthermore, the processing performed by the signal processing unit 13 may be performed using machine learning such as a deep neural network (DNN), a convolutional neural network (CNN), a recurrent neural network (RNN), a generative adversarial network (GAN), or an autoencoder. Alternatively, the processing performed by the signal processing unit 13 may be performed using a dedicated chip such as an image signal processor (ISP). When machine learning is used, the signal processing unit 13 may be configured with a processing device such as a digital signal processor (DSP) or a central processing unit (CPU).

[0025] Here, the imaging device 10 is described as being arranged on a single semiconductor chip (an example of a light receiving unit). Note that if the imaging unit 12 and the signal processing unit 13 are arranged on different semiconductor chips, the imaging unit 12 corresponds to the light receiving unit.

[0026] The arithmetic processing unit 20 performs preprocessing on the depth map generated by the imaging device 10 before the application processor 30 performs processing such as recognition processing on the depth map. The arithmetic processing unit 20 may perform at least a part of the preprocessing using machine learning. The arithmetic processing unit 20 is configured with a processing device such as a DSP or a CPU, for example.

[0027] The application processor 30 may perform various processes, such as recognition processing, on the pre-processed depth map. For example, the application processor 30 recognizes objects present in the depth map and the movements of those objects. At least a portion of the processes performed by the application processor 30 may be performed using machine learning such as DNN, CNN, RNN, GAN, or autoencoder, or may be performed based on a pre-prepared algorithm. The application processor 30 may output the pre-processed or post-processed depth map to an external device such as a cloud server via a predetermined network.

[0028] Note that the configuration of the information processing system 1 is an example and is not limited to the example in Fig. 1. For example, the information processing system 1 does not need to include the arithmetic processing unit 20. In this case, the depth map generated by the imaging device 10 is output directly to the application processor 30.

[0029] Furthermore, the processing performed by the arithmetic processing unit 20 and the application processor 30 is not limited to the above-described example. The application processor 30 may perform processing according to the distance to an object (for example, displaying a warning to the user when the distance to the object is closer than a threshold). The arithmetic processing unit 20 and the application processor 30 may perform various processes using a depth map.

[0030] 2 is a cross-sectional explanatory diagram of the distance measuring device 100 according to the first embodiment of the present disclosure. Fig. 3 is a top view of the distance measuring device 100 according to the first embodiment of the present disclosure. Fig. 4 is a cross-sectional explanatory diagram taken along line A-A shown in Fig. 2.

[0031] 2, the distance measuring device 100 includes a semiconductor substrate 110, an insulating film 111, and a connection pad 112. The distance measuring device 100 also includes a first metal film 120 and a second metal film 122. The distance measuring device 100 also includes a first sidewall portion (dam) 130. １ and the second side wall portion 130 ２ and a first connection portion (bump) 140 １ and the second connection portion 140 ２ The distance measuring device 100 includes an optical member 150, an imaging device 10, and a light emitting unit 15.

[0032] The semiconductor substrate 110 is, for example, a Si (silicon) substrate, and is a circuit board that includes an emission control unit 14 (an example of a drive circuit) that drives the light emitting unit 15. The semiconductor substrate 110 may include circuits other than the emission control unit 14. The semiconductor substrate 110 has an insulating film 111 and first connection pads 112 on one main surface (the upper surface in FIG. 2 ). １ and the second connection pad 112 ２ and,

[0033] First connection pad 112１ The second connection pad 112 connects the light emitting unit 15 to a circuit (for example, the light emission control unit 14) inside the semiconductor substrate 110. ２ connects the imaging device 10 to the circuit inside the semiconductor substrate 110. The first connection pad 112 １ and the second connection pad 112 ２ When there is no need to particularly distinguish between the pads 112 and 113, they are also simply referred to as connection pads 112.

[0034] The semiconductor substrate 110, the insulating film 111, and the connection pads 112 may be collectively referred to as a semiconductor substrate (circuit board).

[0035] The light emitting unit 15 is, for example, a semiconductor chip. The light emitting unit 15 has one or more mesas (not shown) that emit light. As described above, the light emitting unit 15 can be, for example, a VCSEL chip. The VCSEL chip is a back-emitting surface-emitting laser capable of independent light emission.

[0036] The light emitting section 15 has a plurality of connection pads on one main surface (the surface facing one main surface of the semiconductor substrate 110, the surface opposite the other main surface from which light is emitted) of a GaAs (gallium arsenide) base material. The base material of the light emitting section 15 may be a semi-insulating base material such as InP (indium phosphide).

[0037] The imaging device 10 is, for example, a semiconductor chip (image sensor chip). The imaging device 10 includes an imaging element having pixels that can sense light emitted from a subject. As described above, the imaging device 10 may be, for example, a SPAD.

[0038] The image capture device 10 has a plurality of connection pads on one main surface (a surface facing one main surface of the semiconductor substrate 110, a surface opposite the other main surface (light-receiving surface) that receives light) of a GaAs (gallium arsenide) base material. The plurality of connection pads are formed by TSVs (Through-Silicon Vias) that penetrate the image capture device 10. The base material of the image capture device 10 may be a semi-insulating base material such as InP (indium phosphide).

[0039] The optical element 150 is provided on one main surface of the semiconductor substrate 110, between the light-emitting unit 15 and the imaging device 10. The optical element 150 allows a portion of the light emitted by the light-emitting unit 15 to be received by a portion of the light-receiving surface of the imaging device 10 without being reflected by the object. The optical element 150 guides a portion of the light emitted by the light-emitting unit 15 to a partial region of the light-receiving surface of the imaging device 10.

[0040] The optical member 150 includes a connection portion 151 , a transparent member 152 , a reflective film 153 (an example of a reflective member), a metal film 154 , and a metal film 1541 .

[0041] The connection portion 151 has the same configuration as the sidewall portion 130 and the connection portion 140 described later. The connection portion 151 connects the transparent member 152 and the semiconductor substrate 110 via the metal film 154, the metal film 1541, the first metal film 120, and the second metal film 122.

[0042] The transparent member 152 has a rectangular parallelepiped or cubic shape. The transparent member 152 is part of a light guiding unit that guides a portion of the light emitted by the light-emitting unit 15 directly to the image capture device 10, in other words, without being reflected by the object of distance measurement. The shape of the transparent member 152 is not limited to a rectangular parallelepiped or cubic. The transparent member 152 may have any shape, such as a cylinder (or an elliptical cylinder), as long as it guides a portion of the light emitted by the light-emitting unit 15 to the image capture device 10 with the reflective film 153 attached to a portion of the transparent member 152.

[0043] The reflective film 153 is, for example, a metal film, and is provided on the transparent member 152. In the example of Figures 2 and 3, the reflective film 153 is disposed on the surface (upper surface) of the transparent member 152 opposite to the surface in contact with the connection portion 151.

[0044] The reflective film 153 is part of a light guiding section that guides a portion of the light emitted by the light emitting section 15 directly, in other words, without being reflected by the object of distance measurement, to the imaging device 10. After entering the transparent member 152, a portion of the light emitted by the light emitting section 15 is reflected by the reflective film 153 and then emitted from the transparent member 152. This point will be described later with reference to FIG.

[0045] 2 and 3, the first metal film 120 and the second metal film 122 are provided on one main surface of the semiconductor substrate 110 so as to surround the light emitting section 15 and the imaging device 10. The first metal film 120 and the second metal film 122 surrounding the light emitting section 15 and the imaging device 10 are connected to the circuit in the semiconductor substrate 110, the first connection section 140, and the like. １ and the second connection portion 140 ２ is not electrically connected to.

[0046] The first metal film 120 and the second metal film 122 surrounding the light-emitting section 15 and the imaging device 10 function as a light-shielding film that prevents light emitted by the light-emitting section 15 from entering the semiconductor substrate 110 .

[0047] As shown in FIGS. 2 and 4, the first side wall portion 130 １ is the first connection portion 140 １ The first sidewall 130 surrounds the light emitting portion 15 and connects the peripheral portion of the light emitting portion 15 to one main surface of the semiconductor substrate 110. １ The light emitting portion 15 is connected to one main surface of the semiconductor substrate 110 via a first metal film 120 and a second metal film 122 that surround the light emitting portion 15 and the imaging device 10. The light emitting portion 15 is connected to one main surface of the semiconductor substrate 110 via a first sidewall portion 130. １ It is not electrically connected to the light emission control unit 14 in the semiconductor substrate 110 via the

[0048] First side wall portion 130 １ is the metal film 131 １ and the porous metal layer 132 １ The metal film 131 １ is the porous metal layer 132 １ The insulating film 114 is provided on one main surface side of the semiconductor substrate 110 (hereinafter also referred to as the bottom surface) and on a surface perpendicular to the one main surface of the semiconductor substrate 110 (hereinafter also referred to as the side surface).

[0049] First connection portion 140 １ The first side wall portion 130 １ In the area surrounded by the arrow, the connection pads of the light emitting portion 15 and the first connection pads 112 of the semiconductor substrate 110 are １ The first connection portion 140 １is connected to the first connection pad 112 on one main surface of the semiconductor substrate 110 via the first metal film 120 and the second metal film 122. １ The light emitting unit 15 is connected to the first connecting unit 140. １ The light emitting control unit 14 is electrically connected to the semiconductor substrate 110 via the light emitting control unit 14 .

[0050] First connection portion 140 １ is a metal film 141 １ and the porous metal layer 142 １ The metal film 141 １ is the porous metal layer 142 １ The insulating film 114 is provided on a surface (bottom surface) on one main surface side of the semiconductor substrate 110 and a surface (side surface) perpendicular to the one main surface of the semiconductor substrate 110 .

[0051] Second side wall portion 130 ２ is the second connection portion 140 ２ The second sidewall portion 130 connects the peripheral portion of the imaging device 10 to one of the main surfaces of the semiconductor substrate 110 in a manner surrounding the second sidewall portion 130. ２ The second sidewall portion 130 is connected to one main surface of the semiconductor substrate 110 via the first metal film 120 and the second metal film 122. ２ There is no electrical connection to the circuitry within the semiconductor substrate 110 via the

[0052] Second side wall portion 130 ２ is the metal film 131 ２ and the porous metal layer 132 ２ The metal film 131 ２ is the porous metal layer 132 ２ are provided on the bottom and side surfaces of the

[0053] Second connection portion 140 ２ The second side wall portion 130 ２ Within the area surrounded by the arrow, the connection pads of the imaging device 10 and the second connection pads 112 of the semiconductor substrate 110 are ２ The second connection portion 140 ２ is connected to the second connection pad 112 on one main surface of the semiconductor substrate 110 via the first metal film 120 and the second metal film 122. ２ The imaging device 10 is connected to the second connection unit 140.２ The semiconductor substrate 110 is electrically connected to the circuitry therein via the wiring.

[0054] Second connection portion 140 ２ is a metal film 141 ２ and the porous metal layer 142 ２ The metal film 141 ２ is the porous metal layer 142 ２ are provided on the bottom and side surfaces of the

[0055] In addition, the metal film 131 １ and metal film 131 ２ When there is no need to distinguish between the porous metal layer 132 and the porous metal layer 132, the porous metal layer 132 is also simply referred to as the metal film 131. １ and porous metal layer 132 ２ When there is no need to distinguish between the porous metal layer 132 and the porous metal layer 132, the porous metal layer 132 may be simply referred to as the porous metal layer 132. １ and metal film 141 ２ When there is no need to distinguish between the porous metal layer 142 and the porous metal layer 142, the porous metal layer 142 is also simply referred to as the metal film 141. １ and porous metal layer 142 ２ When there is no need to distinguish between the porous metal layer and the porous metal layer, the porous metal layer may be simply referred to as the porous metal layer 142.

[0056] As described above, the connection portion 151 connects the transparent member 152 to one main surface of the semiconductor substrate 110 between the light-emitting portion 15 and the imaging device 10. The connection portion 151 is connected to one main surface of the semiconductor substrate 110 via the first metal film 120 and the second metal film 122. Note that the connection portion 151 is not electrically connected to the circuitry within the semiconductor substrate 110.

[0057] The connection portion 151 includes a metal film 1511 and a porous metal layer 1512. The metal film 1511 is provided on the bottom surface and side surfaces of the porous metal layer 1512.

[0058] 1.3. Example of distance measurement by distance measuring device As described above, the distance measuring device 100 measures the distance to an object to be measured by having the imaging device 10 receive light that is reflected off the object to be measured and that is emitted by the light emitting unit 15. The distance measuring device 100 also generates a reference signal when the light emitted by the light emitting unit 15 is received by the imaging device 10 without being reflected off the object to be measured. The distance measuring device 100 measures the distance to the object to be measured using this reference signal.

[0059] FIG. 5 is a diagram showing an example of distance measurement by the distance measuring device 100 according to the first embodiment of the present disclosure.

[0060] The imaging device 10 instructs the light emission control unit 14 (not shown) in the semiconductor substrate 110 to cause the light emitting unit 15 to emit light. The imaging device 10 also starts measuring time.

[0061] Here, the imaging device 10 and the light-emission control unit 14 are arranged within the same ranging device 100. Furthermore, the light-emission control unit 14 is arranged within the semiconductor substrate 110 on which the imaging device 10 is arranged. Therefore, the distance between the imaging device 10 and the light-emission control unit 14 is shorter than when the light-emission control unit 14 is arranged outside the semiconductor substrate 110, for example, as a semiconductor chip. This allows the ranging device 100 to reduce delays in the exchange of signals (e.g., instructions to emit light) between the imaging device 10 and the light-emission control unit 14.

[0062] The light-emitting unit 15 emits light in response to an instruction from the light-emission control unit 14. Here, the light-emitting unit 15 and the light-emission control unit 14 are arranged within the same distance measuring device 100. Furthermore, the light-emission control unit 14 is arranged within the semiconductor substrate 110 on which the light-emitting unit 15 is arranged. Therefore, the distance between the light-emitting unit 15 and the light-emission control unit 14 is shorter than when the light-emission control unit 14 is arranged outside the semiconductor substrate 110, for example, as a semiconductor chip. This allows the distance measuring device 100 to reduce delays in signal exchange (e.g., instructions to emit light) between the light-emitting unit 15 and the light-emission control unit 14.

[0063] In this way, the distance measuring device 100 according to this embodiment can shorten the distance between the image capturing device 10 and the light emission control unit 14, and the distance between the light emission control unit 14 and the light emitting unit 15. This allows the distance measuring device 100 to reduce the time difference (delay) between when the image capturing device 10 issues a command to emit light and when the light emitting unit 15 actually emits light, thereby improving the distance measuring accuracy of the distance measuring device 100.

[0064] 5, light L1 emitted by the light-emitting unit 15 is reflected by the object Ob of distance measurement and enters the imaging device 10. When the imaging device 10 receives the light L1, it measures a first time period from when the imaging device 10 instructs the light-emitting unit 15 to emit light to when the imaging device 10 receives the light L1.

[0065] Although not shown in Fig. 5, a transparent cover may be provided between the distance measuring device 100 and the object Ob. The transparent cover is made of, for example, glass, plastic, or resin. This cover can prevent dust and the like from entering the distance measuring device 100.

[0066] The light L0 emitted by the light-emitting unit 15 is incident on the imaging device 10 without leaving the distance measuring device 100. More specifically, the light L0 passes through the optical member 150 and is incident on the imaging device 10. When the imaging device 10 receives the light L0, it measures a second time period from when the imaging device 10 instructs the light-emitting unit 15 to emit light to when the imaging device 10 receives the light L0.

[0067] The image capturing device 10 measures the distance to the object Ob using the first time and the second time. For example, the image capturing device 10 measures the distance to the object Ob from the first time using the measurement result using the second time as a reference (e.g., the distance to the object Ob is zero). In this way, the light L0 is used to calibrate the distance measurement by the image capturing device 10.

[0068] Here, the imaging device 10 receives both the light beams L1 and L0. By receiving the light beams L1 and L0 in the same imaging device 10 in this manner, it is possible to shorten the distance between the light emitting unit 15 and the imaging element that receives the light beam L1, and the distance between the light emitting unit 15 and the imaging element that receives the light beam L0. This allows the imaging device 10 to measure the distance to the object Ob with higher accuracy.

[0069] As described above, the light emitting unit 15 and the imaging device 10 are disposed on one main surface of the same semiconductor substrate 110. In this embodiment, by providing the optical member 150 between the light emitting unit 15 and the imaging device 10, the light L0 emitted by the light emitting unit 15 can be received by the imaging device 10.

[0070] By providing the optical member 150 between the light-emitting unit 15 and the image capturing device 10, the distance measuring device 100 can generate a reference signal in the image capturing device 10 while shortening the distance between the image capturing device 10 and the light-emitting unit 15 and the light-emission control unit 14. This allows the distance measuring device 100 to measure the distance to the object Ob with higher accuracy.

[0071] 5, the imaging device 10 includes a partition wall 16 that separates the light receiving surface that receives the light L1 from the light receiving surface that receives the light L0. This makes it difficult for the light L0 to be incident on the imaging element that receives the light L1. The imaging device 10 can measure the distance to the object Ob with higher accuracy.

[0072] 1.4. Detailed Examples of Side Walls and Connections In the distance measuring device 100, the light emitting unit 15 and the image capturing device 10 are flip-chip mounted on the semiconductor substrate 110. The light emitting unit 15 and the image capturing device 10 are electrically connected to the circuitry in the semiconductor substrate 110 by the connection units 140. In addition, in the distance measuring device 100, the space in which the connection pads 112 and the connection units 140 are provided is sealed by the side wall units 130.

[0073] Here, for example, when the light emitting unit 15 is flip-chip mounted on a semiconductor substrate 110 including the light emitting control unit 14 using a general manufacturing method, first, multiple circuits (circuits including the light emitting control unit 14) are formed on a Si wafer.

[0074] Thereafter, the light emitting unit 15 is stacked on the light emission control unit 14 via bulk metal bumps (connecting units), and the connection pads provided on the opposing main surfaces of the light emission control unit 14 and the light emitting unit 15 are connected to each other by the bumps. Similarly, the imaging device 10 is flip-chip mounted on the semiconductor substrate 110. Then, the Si wafer is diced into individual distance measuring devices 100, thereby separating the distance measuring devices 100.

[0075] In the process of dicing the Si wafer into individual distance measuring devices 100, cutting water is supplied to the Si wafer while dicing. If the cutting water gets between the semiconductor substrate 110 and the light emitting section 15 or between the semiconductor substrate 110 and the imaging device 10, it will adversely affect the distance measuring devices 100. For this reason, typically, the Si wafer is diced into individual distance measuring devices 100 after each distance measuring device 100 is sealed with resin.

[0076] However, when sealing the distance measuring device 100 with resin, there are problems such as contamination of the electrodes by the resin, prolonged work time due to the need to inject resin for each distance measuring device 100, and an increase in the amount of resin that is discarded after its expiration date due to the prolonged work time.

[0077] For this reason, there is a technology in which the connection pads provided on the opposing main surfaces of the semiconductor substrate 110 and the light-emitting unit 15 or the imaging device 10 are connected to each other by bumps, and the areas where the connection pads and bumps that need to be sealed are provided are joined and sealed using the same connection method as the connection between the connection pads.

[0078] In addition, in a typical flip-chip mounting, the light-emitting unit 15 (or the imaging device 10) is mounted on the semiconductor substrate 110 by heating bulk metal bumps such as Au (gold), Cu (copper), and solder provided on the semiconductor substrate 110 or on the opposing main surface of the light-emitting unit 15 (or the imaging device 10) while pressing them together.

[0079] However, if the thermal expansion coefficients of the semiconductor substrate 110 and the light-emitting section 15 (or the imaging device 10) differ by, for example, 0.1 ppm / °C or more, the following problems arise when bulk Au, Cu, solder, etc. are used as the bump material.

[0080] For example, if bulk Au is used as the bump material, in order to stably connect the semiconductor substrate 110 and the light emitting unit 15 (or the image capture device 10), which have different thermal expansion coefficients, with the bumps, it is necessary to heat the semiconductor substrate 110 to a high temperature of 300° C. or higher and apply a high pressure of 100 MPa or higher between the semiconductor substrate 110 and the light emitting unit 15 (or the image capture device 10).

[0081] Furthermore, if bulk Cu is used as the bump material, heating to 380° C. or higher is required.

[0082] In this way, when bulk Au or Cu is used as the bump material, the bump connection must be made at high temperature and high pressure, and such high temperature and high pressure may damage the light emitting section 15 and the imaging device 10, and may reduce the reliability of the distance measuring device 100.

[0083] On the other hand, when solder is used as the bump material, bump connections can be made at lower temperatures and pressures than with Au or Cu, but solder is inferior to Au or Cu in heat resistance and connection strength. For this reason, when the light-emitting unit 15 (or the image capture device 10) thermally expands due to heat generated by electronic components such as the light-emitting unit 15, solder bumps are prone to open circuit failure due to the difference in thermal expansion coefficients between the semiconductor substrate 110 and the light-emitting unit 15 (or the image capture device 10). This could reduce the reliability of the distance measuring device 100.

[0084] As described above, the semiconductor substrate 110 according to the present disclosure is a Si substrate, and has a thermal expansion coefficient of 5.7 ppm / ° C. On the other hand, the base material of the light-emitting unit 15 (or the imaging device 10) according to the present disclosure is GaAs, and has a thermal expansion coefficient of 2.6 ppm / ° C.

[0085] As described above, in the distance measuring device 100, the difference in thermal expansion coefficient between the semiconductor substrate 110 and the light emitting unit 15 (or the image capturing device 10) is much greater than 0.1 ppm / ° C. Therefore, if the bump material of the distance measuring device 100 is bulk Au, Cu, or solder, the above-mentioned problems may occur, resulting in a decrease in reliability.

[0086] Furthermore, the periphery of the area between the semiconductor substrate 110 and the light-emitting unit 15 (or the image capture device 10) that needs to be sealed is surrounded by a bulk metal with a plated surface, and then bonded and sealed. In this case, if the thermal expansion coefficients of the semiconductor substrate 110 and the light-emitting unit 15 (or the image capture device 10) differ by, for example, 0.1 ppm / °C or more, cracks will occur in the sealed portion. This will reduce the airtightness of the distance measuring device 100.

[0087] Furthermore, suppose that the semiconductor substrate 110 and the light-emitting unit 15 or the imaging device 10 are stacked together while the semiconductor substrate 110, the light-emitting unit 15, or the imaging device 10 has thickness variations or warpage. In this case, the semiconductor substrate 110 can only be joined to the light-emitting unit 15 or the imaging device 10 at the sealing portion by the protrusion of the convex surface of the plating film.

[0088] As a result, gaps are scattered in the sealed portion of the distance measuring device 100, reducing the airtightness. Furthermore, if the semiconductor substrate 110 and the light emitting unit 15 or the image capturing device 10 are joined by raising the temperature and pressure in order to prevent the occurrence of gaps in the sealed portion, there is a risk of short-circuit failure between adjacent fine bumps of the distance measuring device 100.

[0089] To solve these problems, the connection section 140 of the distance measuring device 100 according to this embodiment includes, for example, a porous metal layer 142 of Au. The porous metal layer 142 includes Au particles with a particle diameter of 0.005 μm to 1.0 μm and a purity of 99.9% by weight or more. The components of the porous metal layer 142 may be, for example, Cu, Ag (silver), or Pt (platinum) with a purity of 99.9% by weight or more.

[0090] The porous metal layer 142, which contains metal particles with a particle diameter of 0.005 μm to 1.0 μm, allows for metal bonding at temperatures lower than the melting point of the bulk metal due to the size effect of the particle diameter. For example, the porous metal layer 142 can connect the semiconductor substrate 110 and the light-emitting unit 15 (or the image capture device 10) at temperatures of approximately 100°C if the component is Au, approximately 250°C if the component is Ag, and approximately 150°C if the component is Cu. This reduces damage to the light-emitting unit 15 (or the image capture device 10) due to heat, thereby improving the reliability of the ranging device 100.

[0091] Furthermore, because the porous metal layer 142 is elastic, it can be elastically deformed even if, for example, the light-emitting unit 15 expands at a thermal expansion rate different from that of the semiconductor substrate 110 due to heat generation from the light-emitting unit 15. The same applies to the imaging device 10. This allows the range finding device 100 to suppress the occurrence of open circuit failures. This allows the range finding device 100 to have improved reliability compared to, for example, a case in which solder bumps are used.

[0092] Such a distance measuring device 100 is manufactured by stacking a light emitting section 15 and an imaging device 10 on a semiconductor substrate 110 having a connection section 140 on its upper surface, and connecting the porous metal layer 142 of the connection section 140 to the connection pads of the light emitting section 15 and the imaging device 10 without melting it.

[0093] As described above, the connection portion 140 includes the metal film 141 between the porous metal layer 142 and the connection pad 112 on the semiconductor substrate 110 side.

[0094] In the present disclosure, the ratio of the film thickness of the metal film 141 to the thickness of the connection portion 140 in the direction perpendicular to the main surface of the semiconductor substrate 110 is set to less than 10%. This enables the connection portion 140 to be fine-pitched to 20 μm or less in the distance measuring device 100. Such fine-pitching will be described later together with the process of forming the connection portion 140.

[0095] Furthermore, as described above, the connection portion 140 also has a metal film 141 on the side surface (peripheral side surface) of the porous metal layer 142. The material of the metal film 141 is preferably the same as that of the porous metal layer 142. For example, if the material of the porous metal layer 142 is Au, the metal film 141 is preferably an Au film.

[0096] As a result, the side surfaces of the porous metal layer 142 of the connection parts 140 are coated with the metal film 141, which can prevent the particles of the porous metal layer 142 from crumbling and scattering. Therefore, the connection parts 140 can prevent adjacent connection parts 140 from shorting out due to scattering of the particles of the porous metal layer 142.

[0097] Furthermore, if the metal film 141 is not provided on the side surface of the porous metal layer 142, the side surface of the porous metal layer 142, which has a relatively soft surface, becomes rough, causing variations in shape between the connecting portions 140.

[0098] In contrast, in the connection parts 140, a metal film 141 harder than the porous metal layer 142 is provided on the side surface of the porous metal layer 142. This suppresses variations in shape among the connection parts 140, resulting in a uniform shape for all of them. Moreover, because the side surface of the connection parts 140 is coated with the relatively hard metal film 141, further miniaturization becomes possible, enabling an even finer pitch.

[0099] Furthermore, when the light emitting unit 15 and the imaging device 10 are flip-chip mounted on the semiconductor substrate 110, the connection portion 140 is slightly crushed in the thickness direction. At this time, the metal film 141, which is harder than the porous metal layer 142, is provided on the side surface of the porous metal layer 142, thereby preventing particles of the porous metal layer 142 from leaking out of the metal film 141. As a result, the particle density of the porous metal layer 142 inside the metal film 141 increases, and the connection portion 140 can reduce the connection resistance.

[0100] The sidewall 130 of the distance measuring device 100 has a structure similar to that of the connection part 140. Specifically, as described above, the sidewall 130 includes a porous metal layer 132 of Au. The porous metal layer 132 includes Au particles with a particle diameter of 0.005 μm to 1.0 μm and a purity of 99.9% by weight or more. The components of the porous metal layer 132 may be, for example, Cu, Ag (silver), or Pt (platinum) with a purity of 99.9% by weight or more.

[0101] As described above, due to the size effect of the particle diameter, the porous metal layer 132 allows metal bonding at a temperature lower than the melting point of the bulk metal. This reduces damage to the light emitting unit 15 and the image capturing device 10 caused by heat when the porous metal layer 132 is formed, thereby improving reliability of the distance measuring device 100.

[0102] Furthermore, because the porous metal layer 132 is elastic, it elastically deforms even if, for example, the light-emitting unit 15 (or the imaging device 10) expands at a thermal expansion coefficient different from that of the semiconductor substrate 110 due to heat generation from the light-emitting unit 15. This makes it possible to prevent cracks from occurring in the sidewall 130, and improves the airtightness of the distance measuring device 100 in the areas where the connection pads 112 and connection units 140 that need to be sealed are provided.

[0103] Furthermore, since the porous metal layer 51 is elastically deformable, even if the semiconductor substrate 110, the light-emitting section 15, or the imaging device 10 has thickness variations or warpage, the porous metal layer 51 will deform to conform to the surface shapes of these when they are joined together.

[0104] As a result, the ranging device 100 can prevent gaps from occurring at the connection parts between the side wall portion 130 and the semiconductor substrate 110, and at the connection parts between the side wall portion 130 and the light-emitting portion 15 and the imaging device 10, thereby improving airtightness.

[0105] 4, the side wall portion 130 is provided so as to surround an area in which the connection pads that need to be sealed and the connection portion 140 are provided, thereby enabling the distance measuring device 100 to alleviate mechanical stress acting on the connection portion 140 provided at the corner when the semiconductor substrate 110, the light emitting portion 15, or the imaging device 10 thermally expands.

[0106] Specifically, for example, when the semiconductor substrate 110 or the light emitting portion 15 thermally expands, the amount of expansion and contraction due to temperature changes increases from the center of the main surface of the semiconductor substrate 110 or the light emitting portion 15 toward the periphery. １ If there is no first connecting portion 140 provided at the corner, １ The same applies when the semiconductor substrate 110 or the imaging device 10 undergoes thermal expansion.

[0107] In contrast, in the distance measuring device 100, the peripheral portions of the light emitting unit 15 and the image capturing device 10 are sealed by the side wall portion 130, and therefore expansion and contraction of the peripheral portions of the light emitting unit 15 and the image capturing device 10 due to temperature changes can be suppressed by the side wall portion 130. This allows the distance measuring device 100 to alleviate mechanical stress on the connection portion 140 provided at the corner portion.

[0108] As described above, the sidewall portion 130 includes the metal film 131 between the porous metal layer 132 and the connection pad 112 on the main surface of the semiconductor substrate 110 .

[0109] In the present disclosure, the ratio of the film thickness of the metal film 131 to the thickness of the sidewall portion 130 in the direction perpendicular to the main surface of the semiconductor substrate 110 is less than 10%. This allows the distance measuring device 100 to achieve a fine pitch of 20 μm or less in the process of simultaneously forming the sidewall portion 130 and the connection portion 140.

[0110] Furthermore, the side wall portion 130 also has a metal film 131 on the side surface (peripheral side surface) of the porous metal layer 132. The material of the metal film 131 is preferably the same as that of the porous metal layer 132. For example, if the material of the porous metal layer 132 is Au, the metal film 131 is preferably an Au film.

[0111] As a result, the side wall portion 130 can prevent particles of the porous metal layer 1322 from crumbling and scattering because the side surface of the porous metal layer 132 is coated with the metal film 131. Therefore, the side wall portion 130 can prevent adjacent connection portions 140 from shorting out due to scattering of particles of the porous metal layer 132.

[0112] Furthermore, if the metal film 131 is not provided on the side surface of the porous metal layer 132, the side surface of the porous metal layer 132, which has a relatively soft surface, becomes rough, causing variations in the side surface shape of the side wall portion 130.

[0113] In contrast, in the side wall portion 130 of the present disclosure, the metal film 131, which is harder than the porous metal layer 132, is provided on the side surface of the porous metal layer 132, so that the variation in the shape of the side surface is suppressed and the entire side surface has a uniform surface shape. Moreover, since the side surface of the side wall portion 130 is coated with the relatively hard metal film 131, further miniaturization is possible.

[0114] Such a distance measuring device 100 is manufactured by stacking a light emitting section 15 and an imaging device 10 on a semiconductor substrate 110 having a side wall section 130 on its upper surface, and connecting the porous metal layer 132 of the side wall section 130 to a connection pad without melting it.

[0115] 6 to 9 are explanatory diagrams showing the process of forming the sidewall portion 130 and the connecting portions 140 and 151 on the semiconductor substrate 110 according to the present disclosure.

[0116] 6, a photoresist layer 160 is formed on the semiconductor substrate 110 on which the insulating film 111, the connection pad 112, the first metal film 120, and the second metal film 122 are formed. Then, by photolithography, through holes 62 and grooves 63 and 64 are formed in the photoresist layer 160 at positions where the sidewall portions 130 and the connection portions 140 and 151 are to be formed, thereby exposing the surface of the first metal film 120.

[0117] At this time, the through holes 62 are formed so that the distance between the centers of adjacent through holes 62 is 20 μm (20 μm pitch). These through holes 62 are filled with a paste 50 (see FIG. 8 ) containing metal particles that will become the material of the porous metal layer 142 in a later process. However, because the through holes 62 have a fine structure with a 20 μm pitch, if the paste 50 is filled in this state, there is a risk that the fine structure will be damaged and collapse.

[0118] 7, a metal film 65 is formed by, for example, sputtering on the upper surface of the photoresist layer 160, the side surfaces of the through-holes 62, the side surfaces of the grooves 63 and 64, and the upper surface of the first metal film 120. A metal having the same composition as the metal particles contained in the paste 50 that will later be filled into the through-holes 62 is selected as the material for the metal film 65. In this example, the metal film 65 is made of Au.

[0119] As a result, the photoresist layer 160 hardens as its surface is coated with the metal film 65, thereby preventing the fine structure from collapsing when the through-holes 62 are filled with a paste 50 containing metal particles.

[0120] Furthermore, if the thickness of the metal film 65 formed here is too thick, the opening of the through-hole 62 will be narrow, making it difficult to fill the through-hole 62 with the paste 50 containing metal particles. １ In other words, the thickness of the connecting portion 140 formed later in the direction perpendicular to the main surface of the semiconductor substrate 110 (the height D of the connecting portion 140) １ ) the thickness d of the metal film 65 １ A thin metal film 65 (for example, less than 1 μm thick) is formed so that the ratio of

[0121] For example, when forming connection portions 140 with a height of 10 μm arranged at a pitch of 20 μm, the thickness of the metal film 65 is set to 0.2 μm. This prevents the opening of the through-hole 62 from narrowing even when the metal film 65 is formed, and therefore allows the through-hole 62 to be sufficiently filled with the paste 50 containing metal particles in a later process.

[0122] As a result, the depth D of the groove 63 ２ In other words, the thickness of the sidewall portion 130 to be formed later in the direction perpendicular to the main surface of the semiconductor substrate 110 (the height D of the sidewall portion 130) ２ ) the thickness d of the metal film 65 １ Similarly, the ratio of the depth D of the groove 64 is less than 10%. ３ In other words, the thickness of the connecting portion 151 to be formed later in the direction perpendicular to the main surface of the semiconductor substrate 110 (the height D of the connecting portion 151) ３ ) the thickness d of the metal film 65１ The ratio is less than 10%.

[0123] 8, the through holes 62 and grooves 63, 64 formed in the photoresist layer 160 are filled with a paste 50 containing Au particles with a purity of 99.9% by weight or more and a particle diameter of 0.005 μm to 1.0 μm. Any method can be used to fill the through holes 62 and grooves 63, 64 with the paste 50, such as screen printing or spreading dropped paste 50 with a spatula.

[0124] Thereafter, the paste 50 is dried and sintered, and the photoresist layer 160 is removed by lift-off using a remover or the like. As a result, as shown in FIG. 9 , the first Au metal film 120, the second Au metal film 122, the Au metal film 141, and the porous metal layer 142 are sequentially stacked on the surface of the connection pad 112. Furthermore, the connection part 140 is completed in which the Au metal film 141 is also formed on the side surface of the porous metal layer 142. The porous metal layer 142 contains Au particles with a particle diameter of 0.005 μm to 1.0 μm.

[0125] At the same time, a first Au metal film 120, a second Au metal film 122, an Au metal film 131, and a porous metal layer 132 are sequentially laminated on the surface of the insulating film 111 so as to surround the region where the connection portion 140 is formed. In addition, a sidewall portion 130 is completed in which the Au metal film 131 is formed on the side surface of the porous metal layer 132. The porous metal layer 132 contains Au particles with a particle diameter of 0.005 μm to 1.0 μm.

[0126] At the same time, the first side wall portion 130 １ and the second side wall portion 130 ２ A first Au metal film 120, a second Au metal film 122, an Au metal film 1511, and a porous metal layer 1512 are sequentially laminated on the surface of the insulating film 111 between the first and second metal films 120 and 1512. The connection part 151 is also completed with the Au metal film 1511 formed on the side surface of the porous metal layer 1512. The porous metal layer 1512 contains Au particles with a particle diameter of 0.005 μm to 1.0 μm.

[0127] In this way, the connection portion 140 is formed between the first and second metal films 120 and 122 on the connection pad 112 and the porous metal layer 142, with a height D １ The metal film 141 has a thickness ratio of less than 10% to the porous metal layer 142. Furthermore, the connection portion 140 also has the metal film 141 on the side surface of the porous metal layer 142.

[0128] The sidewall 130 has a height D between the first and second metal films 120 and 122 on the insulating film 111 and the porous metal layer 132. ２ The metal film 131 has a thickness ratio of less than 10% to the porous metal layer 132. Furthermore, the sidewall portion 130 also has the metal film 131 on the side surface of the porous metal layer 132.

[0129] The connection portion 151 is formed between the first and second metal films 120 and 122 on the insulating film 111 and the porous metal layer 1512, and has a height D ３ The metal film 1511 has a thickness ratio of less than 10% to the porous metal layer 1512. Furthermore, the connecting portion 151 also has the metal film 1511 on the side surface of the porous metal layer 1512.

[0130] These metal films 131, 141, 1511 are formed on the upper surface of the photoresist layer 160, on the side surfaces of the through holes 62 and grooves 63, 64 formed in the photoresist layer 160, and on the surface of the first metal film 120. This makes it possible to prevent the collapse of the fine structures of the sidewall portions 130 and the connection portions 140, 151 patterned on the photoresist layer 160, and enables the pitch of the connection portions 140 to be finer, i.e., 20 μm or less.

[0131] In addition, since the second metal film 122 is formed on the surface of the connection pad 112 by, for example, sputtering, it is firmly bonded to the connection pad 112 even if the connection pad 112 is made of a metal with a different composition from the second metal film 122.

[0132] Furthermore, the metal film 131 may be formed from a metal of a different composition from that of the porous metal layer 132. However, by forming the metal film 131 from the same composition as the metal film 131 and the porous metal layer 132, the porous metal layer 132 is bonded to the metal film 131 with a stronger bonding force than when the porous metal layer 132 is provided on another metal film of a different composition. The same applies to the metal films 141, 1511 and the porous metal layers 142, 1512.

[0133] In addition, if the porous metal layers 132, 142, 1512 are made of a component other than Au (for example, Cu, Ag (silver) or Pt (platinum)), the metal films 131, 141, 1511 may also be made of the same metal as the porous metal layers 132, 142, 1512 (for example, Cu, Ag (silver) or Pt (platinum)).

[0134] Here, it is assumed that the connection portion 151 connecting the transparent member 152 and the main surface of the semiconductor substrate 110 has the same configuration as the side wall portion 130 and the connection portion 140, but the connection portion 151 is not limited to this. The connection portion 151 only needs to be able to connect (bond) the transparent member 152 and the main surface of the semiconductor substrate 110, and may be an adhesive material or the like.

[0135] However, since the connection portion 151 has the same configuration as the side wall portion 130 and the connection portion 140 , the connection portion 151 can be formed simultaneously with the side wall portion 130 and the connection portion 140 .

[0136] Furthermore, in the distance measuring device 100, for example, at least a part of a metal film formed as a metal base, such as the second metal film 122, may be omitted.

[0137] <1.6. Modifications> <1.6.1. First Modification> In the first embodiment described above, the reflective film 153 is provided on the top surface of the transparent member 152, but something other than the reflective film 153 may be provided on the transparent member 152.

[0138] Fig. 10 is a diagram showing a cross-sectional view of a distance measuring device 100A according to a first modified example of the first embodiment of the present disclosure. The distance measuring device 100A shown in Fig. 10 has the same configuration as the distance measuring device 100 shown in Fig. 2, except that a light-shielding film 155 (an example of a light-shielding member) is provided on the side surface of the transparent member 152.

[0139] The light-shielding film 155 is provided on the side of the transparent member 152 facing the imaging device 10 (a surface perpendicular to the main surface of the semiconductor substrate 110), on the top surface side of the transparent member 152. In the example of FIG.

[0140] The light-shielding film 155 may be formed integrally with or separately from the reflective film 153. The light-shielding film 155 may be formed of the same material (e.g., metal) as the reflective film 153, or may be formed of a different material. The light-shielding film 155 may be formed by, for example, surface processing of the transparent member 152.

[0141] By providing the light-shielding film 155 on the side of the transparent member 152 facing the imaging device 10, the light L1A emitted from the light-emitting unit 15 can more reliably enter the imaging element that generates the reference signal of the imaging device 10. In addition, the light L1A is less likely to enter the imaging element that the light L1 (see FIG. 5) is incident on.

[0142] <1.6.2. Second Modification> In the first embodiment described above, the top surface of the transparent member 152 is approximately parallel to the main surface of the semiconductor substrate 110, and the reflective film 153 is also formed approximately parallel to the main surface of the semiconductor substrate 110, but the shape of the top surface and the shape of the reflective film 153 are not limited to this.

[0143] Fig. 11 is a diagram showing a cross-sectional view of a distance measuring device 100B according to a second modified example of the first embodiment of the present disclosure. The distance measuring device 100B shown in Fig. 11 has the same configuration as the distance measuring device 100 shown in Fig. 2, except for an optical member 150B.

[0144] The optical member 150B has the same configuration as the optical member 150 shown in FIG. 2, except that it has a transparent member 152B and a reflective film 153B.

[0145] Transparent member 152B has a curved top surface that is convex in the direction away from the main surface of semiconductor substrate 110 (upward in FIG. 11 ). Reflective film 153B has the same shape as the top surface of transparent member 152B. That is, reflective film 153B has a curved top surface that is convex in the direction away from the main surface of semiconductor substrate 110 (upward in FIG. 11 ). Reflective film 153B is attached to the top surface of transparent member 152B.

[0146] In this manner, in this modification, the reflective film 153B is formed on the top surface of the transparent member 152B that is formed in an arc shape. This makes it easier for the light L1B emitted from the light-emitting unit 15 to be incident on the image sensor that generates the reference signal of the imaging device 10. Also, the light L1B is less likely to be incident on the image sensor that the light L1 (see FIG. 5) is incident on.

[0147] The top surface of the transparent member 152B is not limited to a curved (arcuate) shape, as long as it makes it easier for the light L1B reflected by the reflective film 153B to be incident on the image sensor that generates the reference signal of the imaging device 10, and makes it harder for the light L1 (see FIG. 5) to be incident on the image sensor.

[0148] For example, the distance DB between the center of the top surface (upper surface) of the transparent member 152B and the first metal film 120 (or the semiconductor substrate 110) may be longer than the distance dB between the edge of the top surface (upper surface) of the transparent member 152B on the imaging device 10 side and the first metal film 120 (or the semiconductor substrate 110) (DB > dB).

[0149] For example, the shape of the top surface of transparent member 152B may be a shape in which the center has corners that protrude further from the sides in a direction away from the main surface of semiconductor substrate 110. Alternatively, the top surface of transparent member 152B may be inclined.

[0150] <<2. Second embodiment>> <2.1. Configuration example of distance measuring device> In the first embodiment described above, for example, the rectangular parallelepiped optical member 150 is disposed between the light-emitting unit 15 and the imaging device 10, but the shape of the optical member 150 is not limited to this. For example, the optical member 150 may be a cavity-type optical member 150C that covers the light-emitting unit 15.

[0151] Fig. 12 is a diagram showing a cross-sectional view of a distance measuring device 100C according to a second embodiment of the present disclosure. Fig. 13 is an explanatory cross-sectional view taken along line B-B shown in Fig. 12. The distance measuring device 100C shown in Figs. 12 and 13 has the same configuration as the distance measuring device 100 shown in Fig. 2, except that it has a cavity-type optical member 150C.

[0152] The optical member 150C includes a connecting portion 151C, a transparent member 152C, a reflective film 153C, a metal film 154C, a metal film 1541C, and a light-shielding film 155C.

[0153] The optical member 150C is provided on one main surface of the semiconductor substrate 110 so as to cover the periphery of the light-emitting unit 15. The optical member 150C seals the light-emitting unit 15 and allows a portion of the light emitted by the light-emitting unit 15 to be received by a portion of the light-receiving surface of the imaging device 10 without being reflected by the object. The optical member 150C guides a portion of the light emitted by the light-emitting unit 15 to a partial region of the light-receiving surface of the imaging device 10.

[0154] Except for its shape, connecting portion 151C has the same configuration as connecting portion 151 in Fig. 2. Connecting portion 151C connects transparent member 152C and semiconductor substrate 110 via metal film 154C, metal film 1541C, first metal film 120, and second metal film 122.

[0155] As shown in FIGS. 12 and 13, the connecting portion 151C is connected to the first side wall portion 130. １ The connecting portion 151C connects the transparent member 152C to one of the main surfaces of the semiconductor substrate 110 via the first metal film 120 and the second metal film 122 that surround the light-emitting portion 15 and the imaging device 10.

[0156] The connection portion 151C includes a metal film 1511C and a porous metal layer 1512C. The metal film 1511C is provided on the bottom surface and side surfaces of the porous metal layer 1512C.

[0157] The transparent member 152C seals the light-emitting unit 15 and is part of a light-guiding unit that guides a portion of the light emitted by the light-emitting unit 15 directly to the imaging device 10, in other words, without reflecting off the object of distance measurement. The transparent member 152C is a cavity-type member. The transparent member 152C has a transparent side wall portion 1521C and a transparent top surface portion 1522C.

[0158] The transparent sidewall portion 1521C surrounds the light emitting portion 15 and is connected to one main surface of the semiconductor substrate 110 via the connection portion 151C, the first metal film 120, and the second metal film 122.

[0159] 12 , a reflective film 153C is attached to the top surface of a transparent side wall portion 1521C located between the light-emitting portion 15 and the imaging device 10. In addition, a light-shielding film 155C is attached to the side surface of the transparent side wall portion 1521C located between the light-emitting portion 15 and the imaging device 10, facing the imaging device 10.

[0160] The transparent top surface portion 1522C is disposed inside the top surface side of the transparent side wall portion 1521C. The side surface of the transparent top surface portion 1522C contacts the inner side surface of the top surface side of the transparent side wall portion 1521C. The transparent side wall portion 1521C and the transparent top surface portion 1522C may be integrally formed.

[0161] The transparent member 152C is arranged to cover the light-emitting unit 15, and together with the reflective film 153C and the light-shielding film 155C, it is sufficient if it functions as a light-guiding unit that allows a portion of the light emitted by the light-emitting unit 15 to directly enter the imaging device 10, and its shape is not limited to the example in Figure 12.

[0162] The reflective film 153C is disposed on the top surface of the transparent side wall portion 1521C located between the light-emitting portion 15 and the imaging device 10, and reflects the light L1C emitted by the light-emitting portion 15 and makes it incident on a partial area of ​​the imaging device 10.

[0163] The light-shielding film 155C is provided on the side of the transparent side wall 1521C, which is located between the light-emitting unit 15 and the image capturing device 10, facing the image capturing device 10, on the top surface side of the transparent side wall 1521C. In the example of Fig. 12, one side of the light-shielding film 155C is connected to one side of the reflective film 153C.

[0164] The light-shielding film 155C may be formed integrally with the reflective film 153C or may be formed separately. The light-shielding film 155C may be formed of the same material (e.g., metal) as the reflective film 153C or may be formed of a different material. The light-shielding film 155C may be formed by, for example, surface processing of the transparent member 152C.

[0165] By providing the light-shielding film 155 on the side surface of the transparent side wall portion 1521C facing the imaging device 10, the light L1C emitted from the light-emitting portion 15 more reliably enters the imaging element that generates the reference signal of the imaging device 10. In addition, the light L1C is less likely to enter the imaging element that the light L1 (see FIG. 5) enters.

[0166] The reflective film 153C and the light-shielding film 155C may be arranged on the top surface of the transparent sidewall portion 1521C so that the light L1C is incident on a partial area of ​​the imaging device 10, and the shape and size of the reflective film 153C and the light-shielding film 155C are arbitrary.

[0167] Here, the optical member 150C has the light-shielding film 155C, but similar to FIG. 2, the optical member 150C does not necessarily have to have the light-shielding film 155C.

[0168] 2.2. Steps for forming connection portion Next, steps for forming connection portion 151C according to the present disclosure will be described with reference to Figures 14 to 17. Figures 14 to 17 are explanatory views showing steps for forming connection portion 151C on semiconductor substrate 110 according to the second embodiment of the present disclosure. Note that descriptions of steps that are the same as those described with reference to Figures 6 to 9 will be omitted.

[0169] 14 , a photoresist layer 160 is formed on the semiconductor substrate 110 on which the insulating film 111, the connection pad 112, the first metal film 120, and the second metal film 122 are formed. Then, by photolithography, through holes 62 and grooves 63 and 64C are formed in the photoresist layer 160 at positions where the sidewall portions 130 and the connection portions 140 and 151C are to be formed, thereby exposing the surface of the first metal film 120.

[0170] Next, a metal film 65 is formed as shown in Figure 15. The thickness of the metal film 65 may be the same as that of the metal film 65 shown in Figure 7.

[0171] 16, the through holes 62 and grooves 63, 64 formed in the photoresist layer 160 are filled with a paste 50 containing Au particles with a purity of 99.9% by weight or more and a particle diameter of 0.005 μm to 1.0 μm. Any method can be used to fill the through holes 62 and grooves 63, 64 with the paste 50, such as screen printing or spreading dropped paste 50 with a spatula.

[0172] Thereafter, the paste 50 is dried and sintered, and then the photoresist layer 160 is removed by lift-off using a remover or the like. As a result, as shown in FIG. 17, the first sidewall portion 130 １A first Au metal film 120, a second Au metal film 122, an Au metal film 1511C, and a porous metal layer 1512C are sequentially stacked on the surface of the insulating film 111 so as to surround the region where the first Au metal film 120, the second Au metal film 122, an Au metal film 1511C, and a porous metal layer 1512C are formed. A connection portion 151C is also completed in which an Au metal film 1511C is formed on the side surface of the porous metal layer 1512C. The porous metal layer 1512C contains Au particles with a particle diameter of 0.005 μm to 1.0 μm.

[0173] Here, it is assumed that the connecting portion 151C connecting the transparent member 152C and the main surface of the semiconductor substrate 110 has the same configuration as the side wall portion 130 and the connecting portion 140, but the connecting portion 151C is not limited to this. The connecting portion 151C only needs to be able to connect (bond) the transparent member 152C and the main surface of the semiconductor substrate 110, and may be an adhesive material or the like.

[0174] However, since the connection portion 151C has the same configuration as the side wall portion 130 and the connection portion 140, the connection portion 151C can be formed simultaneously with the side wall portion 130 and the connection portion 140.

[0175] As described above, the ranging device 100 according to the second embodiment of the present disclosure is equipped with a cavity-type optical element 150C, which seals the light-emitting unit 15 and allows the light L1C emitted by the light-emitting unit 15 to enter the imaging device 10 without being reflected by the object Ob.

[0176] <2.3. Modifications> <2.3.1. First Modification> In the second embodiment described above, the reflective film 153C is provided on the top surface of the transparent side wall portion 1521C, and the light-shielding film 155C is provided on the side surface, but the arrangement of the reflective film 153C and the light-shielding film 155C is not limited to this.

[0177] Fig. 18 is a diagram showing a cross-sectional view of a distance measuring device 100D according to a first modified example of the second embodiment of the present disclosure. The distance measuring device 100D shown in Fig. 18 has the same configuration as the distance measuring device 100C shown in Fig. 12, except that an optical member 150D has a reflective film 153D and a light-shielding film 155D.

[0178] The reflective film 153D is disposed on the side of the transparent top surface portion 1522C on the imaging device 10 side, facing the main surface of the semiconductor substrate 110. That is, the reflective film 153D is disposed on one main surface of the transparent top surface portion 1522C so as to face the main surface of the semiconductor substrate 110. The reflective film 153D is also disposed so as to contact the side surface of the transparent side wall portion 1521C on the imaging device 10 side.

[0179] The light-shielding film 155D is disposed on the transparent side wall portion 1521C on the imaging device 10 side, on the side of the light-emitting portion 15. The light-shielding film 155D is disposed so as to be in contact with the surface of the transparent top surface portion 1522C on which the reflective film 153D is disposed. One side of the light-shielding film 155D is connected to one side of the reflective film 153D.

[0180] The light-shielding film 155D may be formed integrally with the reflective film 153D or may be formed separately. The light-shielding film 155D may be formed of the same material (e.g., metal) as the reflective film 153D or may be formed of a different material. The light-shielding film 155D may be formed by, for example, surface processing of the transparent member 152D.

[0181] By providing the light-shielding film 155D on the side of the inner circumferential surface of the transparent side wall portion 1521C facing the imaging device 10, the light L1D emitted from the light-emitting portion 15 is more likely to be incident on the imaging element that generates the reference signal of the imaging device 10. In addition, the light L1D is less likely to be incident on the imaging element on which the light L1 (see FIG. 5) is incident.

[0182] The reflective film 153D and the light-shielding film 155D may be arranged on the top surface of the transparent sidewall portion 1521C so that the light L1D is incident on a partial area of ​​the imaging device 10, and the shape and size of the reflective film 153D and the light-shielding film 155D may be arbitrarily selected.

[0183] In the second embodiment, the reflective film 153D and the light-shielding film 155D are disposed on the outer side of the transparent member 152C (the side on which the image pickup device 10 is disposed) and closer to the image pickup device 10.

[0184] On the other hand, in this modified example, by arranging the reflective film 153D and the light-shielding film 155D on the inside of the transparent member 152C (the side where the light-emitting unit 15 is arranged) closer to the imaging device 10, the ranging device 100D can more reliably direct light L1D into the desired area of ​​the imaging device 10.

[0185] 19 is a diagram showing a cross-sectional view of a distance measuring device 100E according to a second modification of the second embodiment of the present disclosure. The distance measuring device 100E shown in Fig. 19 has the same configuration as the distance measuring device 100C shown in Fig. 12, except that an optical member 150E has a reflective film 153E and a light-shielding film 155E.

[0186] The reflective film 153E is disposed on the side of the transparent top surface portion 1522C on the imaging device 10 side, facing the main surface of the semiconductor substrate 110. That is, the reflective film 153E is disposed on one main surface of the transparent top surface portion 1522C so as to face the main surface of the semiconductor substrate 110. The reflective film 153E is also disposed so as to contact the side surface of the transparent side wall portion 1521C on the imaging device 10 side.

[0187] The light-shielding film 155E is disposed on the transparent side wall portion 1521C on the imaging device 10 side, on the side facing the imaging device 10. The light-shielding film 155E is disposed on the side face of the transparent side wall portion 1521C facing the imaging device 10, closer to the top surface. The light-shielding film 155E is disposed so that the edge on the semiconductor substrate 110 side is located lower (closer to the semiconductor substrate 110) than the surface of the transparent top surface portion 1522C on which the reflective film 153E is disposed.

[0188] The light-shielding film 155D may be formed of the same material (e.g., metal) as the reflective film 153D, or may be formed of a different material. The light-shielding film 155D may be formed by, for example, surface processing of the transparent member 152D.

[0189] By providing the light-shielding film 155D on the side surface of the transparent side wall portion 1521C facing the imaging device 10, the light L1E emitted from the light-emitting portion 15 more reliably enters the imaging element that generates the reference signal of the imaging device 10. In addition, the light L1E is less likely to enter the imaging element onto which the light L1 (see FIG. 5) is incident.

[0190] The reflective film 153E and the light-shielding film 155E may be arranged on the top surface of the transparent member 152C so that the light L1E is incident on a partial area of ​​the imaging device 10, and the shape and size of the reflective film 153E and the light-shielding film 155E may be arbitrarily chosen.

[0191] In this modification, the reflective film 153E is disposed on the inner side of the transparent member 152C (the side where the light-emitting unit 15 is disposed) closer to the image capture device 10, and the light-shielding film 155E is disposed on the outer side of the transparent member 152C (the side where the image capture device 10 is disposed) closer to the image capture device 10. This allows the distance measuring device 100E to more reliably direct the light L1E to a desired area of ​​the image capture device 10.

[0192] <<3. Summary>> Although the embodiments of the present disclosure have been described above, the technical scope of the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure. Furthermore, components of the embodiments and modifications may be combined as appropriate.

[0193] Furthermore, the effects of each embodiment described in this specification are merely examples and are not intended to be limiting, and other effects may also be obtained.

[0194] The present disclosure may also be configured as follows: (1) A distance measuring device comprising: a circuit board; a light emitting unit disposed on a main surface of the circuit board; a first connection unit including a porous metal layer and electrically connecting the light emitting unit and the circuit board; a first side wall unit including a porous metal layer and provided between the light emitting unit and the circuit board so as to surround the first connection unit; a light receiving unit disposed on the main surface of the circuit board and receiving light emitted by the light emitting unit; a second connection unit including a porous metal layer and electrically connecting the light receiving unit and the circuit board; a second side wall unit including a porous metal layer and provided between the light receiving unit and the circuit board so as to surround the second connection unit; a transparent member provided on the main surface of the circuit board between the light emitting unit and the light receiving unit; and a reflective member provided on the transparent member and guiding a portion of the light emitted by the light emitting unit to a partial area of ​​the light receiving unit. (2) The distance measuring device according to (1), wherein the reflective member is provided on an upper surface of the transparent member facing the main surface of the circuit board. (3) The distance measuring device according to (2), wherein the distance between the upper surface of the transparent member and the main surface of the circuit board is shorter on the side facing the light receiving unit than on the center. (4) The distance measuring device according to (2) or (3), further comprising a light-shielding member provided on the upper surface side of the transparent member on the side facing the light receiving unit. (5) The distance measuring device according to any one of (1) to (3), wherein the transparent member is a cavity-type member that covers the light emitting unit. (6) The distance measuring device according to (5), wherein the reflective member is provided on a top surface of the transparent member facing the main surface of the circuit board. (7) The distance measuring device according to (6), wherein the reflective member is arranged on the surface of the top surface of the transparent member facing the light emitting unit, closer to the light receiving unit. (8) The distance measuring device according to any one of (5) to (7), further comprising a light-shielding member provided on the side of the transparent member facing the light receiving unit. (9) The distance measuring device according to any one of (1) to (8), further comprising a third connection portion including a porous metal layer and connecting the transparent member and the circuit board.(10) The distance measuring device according to any one of (1) to (9), wherein the portion of the light guided to the light receiving unit by the reflecting member is used for calibrating distance measurement using the light emitting unit and the light receiving unit. (11) The distance measuring device according to any one of (1) to (10), further comprising a drive circuit formed in the circuit board and driving the light emitting unit. (12) The distance measuring device according to any one of (1) to (11), wherein the circuit board includes silicon. (13) The distance measuring device according to any one of (1) to (12), wherein the light emitting unit emits laser light from a back surface opposite to a surface connected to the main surface of the circuit board. (14) The distance measuring device according to any one of (1) to (13), wherein the light emitting unit has one or more mesas for emitting light. (15) The distance measuring device according to any one of (1) to (14), wherein the light emitting unit is a Vertical Cavity Surface Emitting Laser (VCSEL). (16) The distance measuring device according to any one of (1) to (15), wherein the light receiving unit is a Single Photon Avalanche Diode (SPAD). (17) The distance measuring device according to any one of (1) to (16), wherein the porous metal layer of at least one of the first connecting unit, the second connecting unit, the first sidewall unit, and the second sidewall unit contains metal particles having a particle diameter of 0.005 μm to 1.0 μm. (18) The distance measuring device according to any one of (1) to (17), wherein at least one of the first connecting unit, the second connecting unit, the first sidewall unit, and the second sidewall unit includes a first metal film provided between the porous metal layer and the circuit board, and a second metal film provided on a side surface of the porous metal layer. (19) The distance measuring device according to (18), wherein the ratio of the film thickness of the second metal film to half the thickness of at least one of the first connecting portion, the second connecting portion, the first side wall portion, and the second side wall portion in a direction perpendicular to the main surface is less than 10%. (20) The distance measuring device according to (18) or (19), wherein the materials of the porous metal layer, the first metal film, and the second metal film are the same type of metal. (21) The distance measuring device according to any one of (1) to (19), wherein the material of the porous metal layer is a porous metal containing gold, silver, platinum, or copper with a purity of 99.9% by weight or more.

[0195] REFERENCE SIGNS LIST 10 Imaging device 14 Light emission control unit 15 Light emitting unit 100, 100A, 100B, 100C, 100D, 100E Distance measuring device 110 Semiconductor substrate 130 Side wall portion 140, 151, 151C Connection portion 150, 150B, 150C, 150D, 150E Optical member 152, 152B, 152C, 152D Transparent member 153, 153B, 153C, 153D, 153E Reflective film 155, 155C, 155D, 155E Light-shielding film

Claims

a first connection portion including a porous metal layer and electrically connecting the light emitting portion and the circuit board; a first side wall portion including a porous metal layer and provided between the light emitting portion and the circuit board so as to surround the first connection portion; a light receiving portion disposed on the main surface of the circuit board and receiving light emitted by the light emitting portion; a second connection portion including a porous metal layer and electrically connecting the light receiving portion and the circuit board; a second side wall portion including a porous metal layer and provided between the light receiving portion and the circuit board so as to surround the second connection portion; a transparent member provided on the main surface of the circuit board between the light emitting portion and the light receiving portion; and a reflective member provided on the transparent member for directing a portion of the light emitted by the light emitting portion to a partial area of ​​the light receiving portion.

2. The distance measuring device according to claim 1, wherein the reflective member is provided on an upper surface of the transparent member that faces the main surface of the circuit board.

3. The distance measuring device according to claim 2, wherein the distance between the top surface of the transparent member and the main surface of the circuit board is shorter on the side facing the light receiving unit than on the center.

4. The distance measuring device according to claim 2, further comprising a light-shielding member provided on the upper surface side of the transparent member, the side facing the light receiving unit.

5. The distance measuring device according to claim 1, wherein the transparent member is a cavity-type member that covers the light emitting portion.

6. The distance measuring device according to claim 5, wherein the reflective member is provided on a top surface of the transparent member that faces the main surface of the circuit board.

7. The distance measuring device according to claim 6, wherein the reflective member is disposed on the surface of the top surface of the transparent member facing the light emitting unit, closer to the light receiving unit.

8. The distance measuring device according to claim 5, further comprising a light blocking member provided on the side of said transparent member facing said light receiving section.

9. The distance measuring device according to claim 1, further comprising a third connection portion having a porous metal layer and connecting said transparent member and said circuit board.

10. A distance measuring device as described in claim 1, wherein the portion of the light guided to the light receiving section by the reflecting member is used for calibration of distance measurement using the light emitting section and the light receiving section.

11. The distance measuring device according to claim 1, further comprising a drive circuit formed within said circuit board for driving said light emitting section.

12. The distance measuring device of claim 1, wherein the circuit board comprises silicon.

13. The distance measuring device according to claim 1, wherein the light emitting section emits laser light from a back surface opposite to a front surface connected to the main surface of the circuit board.

14. The distance measuring device according to claim 1, wherein the light emitting portion has one or more mesas for emitting light.

15. The distance measuring device according to claim 1, wherein the light emitting unit is a Vertical Cavity Surface Emitting Laser (VCSEL).

16. The distance measuring device according to claim 1, wherein the light receiving unit is a Single Photon Avalanche Diode (SPAD).

Images