Light detection device array

Abstract

The present invention relates to a light detection device array and, more specifically, to a light detection device array in which each light detection device can be individually controlled and which can reduce ROIC internal complexity and manufacturing costs. The light detection device array according to an embodiment of the present invention comprises: a substrate; a plurality of light detection devices arranged in M rows (M is a natural number greater than 2) and two columns on the substrate; a quenching resistor disposed on the substrate, electrically connected to a contact electrode, and including conductive lines having a zigzag or serpentine shape and continuously arranged in the row direction; and a bonding pad disposed on the substrate and configured to be electrically connected to the quenching resistor.

Description

Optical detector array

[0001] The present invention relates to an array of photodetectors, and more specifically, to an array of photodetectors that can individually control each photodetector and reduce the internal complexity and manufacturing costs of the ROIC.

[0002] LiDAR (Light Detection And Ranging) technology includes photodetectors for detecting light. SPADs are actively used as photodetectors in LiDAR technology. SPAD stands for Single-Photon Avalanche Diode. SPADs are highly sensitive photodetectors capable of detecting single photons (the smallest unit of light). SPADs have a structure that detects weak optical signals by amplifying them into large current signals through the avalanche phenomenon. However, if the avalanche current is not rapidly dissipated (quenched) after it occurs, the device's recharge time becomes prolonged, making it difficult to detect continuous optical signals. This leads to problems such as degraded response speed and performance of the sensor.

[0003] In conventional LiDAR technology, photodetectors are implemented in various array forms. The structure of the photodetector array is a critical factor in determining the performance of the LiDAR.

[0004] When applying a conventional photodetector array as a SPAD sensor in Geiger mode, if multiple photodetectors are arranged in an (M*N) matrix (where M and N are natural numbers greater than 2), the quenching resistors had to be implemented inside an external ROIC (Readout Integrated Circuit). Implementing the quenching resistors in the ROIC in this way increases the complexity of the internal configuration of the ROIC, leading to higher ROIC costs, and also makes it difficult to apply to general-purpose ROICs.

[0005] The problem that the present invention aims to solve is to provide an array of light detection elements capable of individually controlling each light detection element.

[0006] In addition, it provides an array of photodetector elements that can reduce internal complexity and manufacturing costs within the ROIC.

[0007] In addition, a photodetector array is provided that can secure a placement space in which a microlens array can be placed.

[0008] In addition, a photodetector array is provided that can efficiently arrange bonding pads of multiple photodetectors on a substrate.

[0009] An array of light detection elements according to one embodiment of the present invention comprises: a substrate; a plurality of light detection elements configured to be arranged in M ​​(where M is a natural number greater than 2) rows and 2 columns respectively on the substrate; a quenching resistor disposed on the substrate and electrically connected to the light detection elements, having a conductive line having a zigzag or wavy shape and continuously configured in the row direction; and a bonding pad disposed on the substrate and configured to be electrically connected to the quenching resistor.

[0010] Using the optical detection element array according to an embodiment of the present invention has the advantage of being able to control each optical detection element individually.

[0011] In addition, there is the advantage of being able to reduce internal complexity and manufacturing costs of the ROIC.

[0012] In addition, there is the advantage of securing placement space where a micro-lens array can be placed.

[0013] In addition, there is an advantage in that bonding pads of multiple photodetectors can be efficiently placed on a substrate.

[0014] FIG. 1 is a plan view of an array of light detection elements according to one embodiment of the present invention.

[0015] Figure 2 is an enlarged view of A shown in Figure 1.

[0016] Figure 3 is an enlarged view of C shown in Figure 2.

[0017] Figure 4 is an enlarged view of B shown in Figure 1.

[0018] Embodiments are described in detail using drawings. However, the present invention is not limited to the description below, and it is readily understood by those skilled in the art that various changes to its form and details can be made without departing from the spirit and scope of the invention. Therefore, the present invention is not to be interpreted as being limited to the contents of the embodiments described below.

[0019] Furthermore, in the configuration of the invention described below, the same reference numerals are commonly used across different drawings for identical parts or parts having the same function, and their repetitive descriptions are omitted. Additionally, when referring to parts having the same function, the hatching pattern is identical, and in some cases, no specific reference numeral is assigned.

[0020] The actual location, size, and range of each component shown in the drawings may not be indicated to facilitate understanding. Therefore, the disclosed invention is not necessarily limited to the location, size, and range disclosed in the drawings.

[0021] FIG. 1 is a plan view of an array of light detection elements according to one embodiment of the present invention, FIG. 2 is an enlarged view of A shown in FIG. 1, and FIG. 3 is an enlarged view of C shown in FIG. 2.

[0022] Referring to FIGS. 1 and 2, an array of light detection elements according to one embodiment of the present invention may be implemented on a rectangular substrate (101) having a predetermined length (L) and width (W), wherein the length (L) is longer than the width (W). Herein, the length (L) direction may be defined as a first direction or a column direction, and the width (W) direction may be defined as a second direction or a row direction. Although other configurations are described below in the row direction and column direction, other configurations may also be described in the length (L) direction or the first direction, and in the width (W) direction or the second direction.

[0023] An array of light detection elements according to one embodiment of the present invention comprises a plurality of light detection elements (110) disposed on a substrate (101). The plurality of light detection elements (110) are arranged according to a predetermined arrangement condition. The plurality of light detection elements (110) are arranged such that M (where M is a natural number greater than 2) are arranged in the column direction and 2 are arranged in the row direction. In other words, the array of light detection elements is an array comprising light detection elements (110) arranged in an (M*2) matrix. Here, M is a natural number greater than 2.

[0024] By using an array of light detection elements (110) arranged in such an (M*2) matrix, there is an advantage in that the quenching resistor (140), which will be described later, can be arranged integrally on the substrate (101) for each light detection element (110).

[0025] Since a plurality of photodetector elements (110) have an array structure of an (M*2) matrix, a plurality of photodetector elements (110) are arranged in the first and second columns, which are two columns in the column direction. According to this array structure, there is an advantage that the quenching resistor (140) can be implemented together on the substrate (101). Therefore, there is no need to implement the quenching resistor inside an external ROIC like in a conventional photodetector element array.

[0026] One photodetector (110), a contact electrode (120), a first trace line (130), a quenching resistor (140), a second trace line (150), and a bonding pad (160) are arranged in order from the central axis (X) of the substrate (101) in the right row direction. Likewise, another photodetector, a contact electrode, a first trace line, a quenching resistor, a second trace line, and a bonding pad are arranged in order from the central axis (X) of the substrate (101) in the left row direction.

[0027] A plurality of photodetector elements (110), a plurality of contact electrodes (120), a plurality of first trace lines (130), a plurality of quenching resistors (140), a plurality of second trace lines (150), and a plurality of bonding pads (160) are arranged symmetrically with respect to the central axis (X) of the substrate (101).

[0028] The first electrodes of the plurality of photodetectors (110) are configured as individual electrodes to be controlled individually, and the second electrodes can be configured as a single common electrode. Here, the first electrode may be an anode and the second electrode may be a cathode. With these plurality of photodetectors (110), there is an advantage that a combination of photodetectors is possible freely depending on the lidar driving method.

[0029] The first electrode, which is an individual electrode of each light detection element (110), can be configured to be electrically connected to the contact electrode (120).

[0030] The contact electrode (120) has a shape that extends for a predetermined length in the row direction. The contact electrode (120) may have two ends. One end of the contact electrode (120) is placed on the light detection element (110) and is electrically connected to the light detection element (110), and the other end may be electrically connected to the first trace line (120).

[0031] The first trace line (120) has a shape that extends for a predetermined length in the row direction. One end of the first trace line (120) is electrically connected to a contact electrode (120), and the other end is electrically connected to a quenching resistor (140).

[0032] The thickness in the thermal direction of the first trace line (120) can be configured to be relatively thinner than the thickness in the thermal direction of the contact electrode (120). Here, the thickness in the thermal direction of the first trace line (120) refers to a constant thickness of the intermediate portion formed between the two ends of the first trace line (120). The thickness of the two ends of the first trace (120) can be formed to be thicker than the thickness of the intermediate portion for electrical connection with the contact electrode (120) or the quenching resistor (140).

[0033] The length of the first trace line (120) in the row direction may have a predetermined length to secure a space for a micro-lens array (MLA) to be applied to a plurality of light detection elements (110).

[0034] The length of the first trace line (120) in the row direction may be formed to be longer than the length of the contact electrode (120) in the row direction. The first trace line (120) and other first trace lines may have a constant length in the row direction.

[0035] The quenching resistor (140) has a predetermined length in the row direction. The quenching resistor (140) may be composed of conductive lines having a constant thickness arranged continuously along the row direction in a zigzag or meander shape.

[0036] The length of the quenching resistor (140) in the row direction can be formed to be longer than the length in the row direction of the first trace line (130). The length of the quenching resistor (140) in the column direction can be formed to be longer than the thickness in the column direction of the first trace line (130).

[0037] One end of the quenching resistor (140) is electrically connected to the first trace line (130), and the other end is electrically connected to the second trace line (150).

[0038] The second trace line (150) has a shape that extends in the row direction. One end of the second trace line (150) is electrically connected to a quenching resistor (140), and the other end is electrically connected to a bonding pad (160).

[0039] The length of the second trace line (150) in the row direction may have a first length and a second length depending on the arrangement position of the plurality of photodetector elements (110). Here, the first length is different from the second length, and is defined as the first length being relatively shorter than the second length.

[0040] The row-direction length of a second trace line (150) electrically connected to one of the plurality of light detection elements (110) has a first length. The row-direction length of a second trace line (150') electrically connected to another light detection element (110') arranged below or above the one light detection element (110) in a column direction has a second length.

[0041] In order to electrically connect the quenching resistor connected to the other photodetector (110') to the bonding pad (160'), the second length is formed to be longer than the sum of the first length and the length in the row direction of the bonding pad (160).

[0042] The first length of the second trace line (150) electrically connected to the photodetector element (110) located at the odd number from the top among the photodetector elements (110) arranged in the column direction of the substrate (101) is shorter than the second length of the second trace line (150') electrically connected to the photodetector element (110') located at the even number.

[0043] The bonding pad (160) is electrically connected to the other end of the second trace line (150). The bonding pad (160) is placed or corresponds to one-to-one for each light detection element (110).

[0044] Bonding pads (160) may be arranged at different positions depending on the arrangement position of a plurality of light detection elements (110). More specifically, a bonding pad (160, hereinafter referred to as the first bonding pad) electrically connected to one light detection element (110) located at an odd number along the column direction of the substrate (101) among the plurality of light detection elements (110) may be placed adjacent to a second trace line (150') electrically connected to another light detection element (110') located at an even number. Additionally, the first bonding pad (160) may be placed at a predetermined distance in the row direction from the bonding pad (160', hereinafter referred to as the second bonding pad) electrically connected to the other light detection element (110').

[0045] First bonding pads (160) and second trace lines (150') may be arranged alternately one by one along the thermal direction of the substrate (101). A second trace (150') connected to a second bonding pad (160') may be arranged between two first bonding pads (160) arranged along the thermal direction of the substrate (101).

[0046] The length of the second bonding pad (160') in the row direction may be formed to be shorter than the length of the first bonding pad (160) in the row direction. Additionally, the length of the second bonding pad (160') in the column direction may be formed to be longer than the length of the first bonding pad (160) in the column direction.

[0047] The lengths of the first bonding pad (160) and the second bonding pad (160') in the row or column direction may differ from each other, but their surface areas may be the same or substantially the same.

[0048] The length in the column direction of the first bonding pad (160) and the second bonding pad (160') can be formed to be longer than the length in the column direction (vertical length) of the quenching resistor (140). The length in the row direction of the first bonding pad (160) and the second bonding pad (160') can be formed to be shorter than the length in the row direction of the quenching resistor (140).

[0049] Due to the different first and second lengths of the second trace lines (150, 150') and the different arrangement positions and shapes of the bonding pads (160, 160'), there is an advantage that as many bonding pads (160, 160') as possible can be arranged on a limited substrate (101). If all bonding pads (160, 160') are arranged in a row in the column direction, the spacing between the multiple photodetectors (110, 110') must be widened in the column direction to secure the area of ​​the bonding pads (160, 160'). In this way, the number of photodetectors (110, 110') arranged on the upper surface of the limited substrate (101) is reduced. However, multiple bonding pads (160, 160') are alternately arranged one by one along two columns in the column direction to secure the area of ​​the bonding pads (160, 160'), and accordingly, since the length of the second trace line (150, 150') is configured differently, there is no need to reduce the spacing in the column direction between multiple photodetectors (110, 110'). Therefore, as many photodetectors (110) as possible can be placed on the upper surface of a limited substrate (101).

[0050] Figure 4 is an enlarged view of B shown in Figure 1.

[0051] Referring to FIGS. 1 and FIGS. 4, an optical detection element array according to one embodiment of the present invention may include a microlens array (MLA, 170).

[0052] The micro-lens array (170) is arranged to cover a plurality of photodetectors (110), a plurality of contact electrodes (120), and a plurality of first trace lines (130). Additionally, the micro-lens array (170) may be arranged to cover a portion of a plurality of quenching resistors (140).

[0053] The substrate (101) may include alignment keys (1011) for alignment with the micro-lens array (170). Correspondingly, the micro-lens array (170) may also include an alignment key (1701) for alignment with the substrate (101).

[0054] The micro lens array (170) can be aligned on the substrate (101) by aligning the alignment keys (1101, 1701) of the substrate (101) and the micro lens array (170).

[0055] The substrate (101) may further include an MLA circle and a PDA circle. The MLA circle is a circular marker or pattern used as a specific alignment standard in a microlens array (170). The PDA circle is a circular pattern or marker that establishes a specific standard in a photodiode array.

[0056] According to an array of light detection elements according to an embodiment of the present invention illustrated in FIGS. 1 to 4, a plurality of light detection elements (110) are arranged in a (M*2) matrix, and for each light detection element (110), one electrode is common and another electrode is electrically connected to a quenching resistor (140) and a bonding pad (160), thereby allowing the plurality of light detection elements (110) to be operated individually. In addition, by placing the quenching resistor (140) on a substrate (101), problems such as complexity or increased cost of the ROIC caused by conventionally having a quenching resistor inside the ROIC can be resolved.

[0057] The features, structures, effects, etc. described in the embodiments above are included in one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment may be combined or modified and implemented in other embodiments by a person skilled in the art to which the embodiments belong. Accordingly, details regarding such combinations and modifications should be interpreted as being included within the scope of the present invention.

[0058] Furthermore, although the embodiments have been described above, this is merely illustrative and does not limit the invention. Those skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments may be modified. Differences related to such modifications and applications should be interpreted as being included within the scope of the invention as defined in the appended claims.

Claims

1. Substrate; A plurality of photodetectors configured to be arranged in M ​​(where M is a natural number greater than 2) rows and 2 columns, respectively, on the substrate; A quenching resistor disposed on the substrate, electrically connected to the photodetector, and having a conductive line having a zigzag or serpentine shape continuously configured in the row direction; and A bonding pad disposed on the substrate and configured to be electrically connected to the quenching resistor; An array of light detection elements including 2. In Paragraph 1, A contact electrode disposed on the substrate, electrically connected to each of the photodetectors, and configured to extend along the row direction; and An array of photodetector elements further comprising: a first trace line electrically connected between the contact electrode and the quenching resistor and configured to extend in the row direction and have a predetermined length.

3. In Paragraph 2, An array of photodetector elements, wherein the length of the first trace line in the row direction is longer than the length of the contact electrode in the row direction.

4. In Paragraph 2, An array of photodetector elements, wherein the thickness of the first train line in the column direction is shorter than the length of the contact electrode in the column direction.

5. In Paragraph 2, An array of photodetector elements, wherein the thickness of the first train line in the thermal direction is shorter than the length of the quenching resistor in the thermal direction.

6. In Paragraph 1, An array of light detection elements further comprising: a second trace line electrically connected between the quenching resistor and the bonding pad, extended in the row direction, and configured to have a predetermined length.

7. In Paragraph 6, Among the photodetectors arranged in a row direction among the plurality of photodetectors, the second trace line electrically connected to the first photodetectors positioned at the odd-numbered position from the top has a first length, and the second trace line electrically connected to the second photodetectors positioned at the even-numbered position has a second length. An array of light detection elements, wherein the first length and the second length are different.

8. In Paragraph 1, The bonding pads include first bonding pads electrically connected to first photodetectors positioned at odd-numbered positions from the top among the photodetectors arranged in a row direction in the plurality of photodetectors, and second bonding pads electrically connected to second photodetectors positioned at even-numbered positions. The first bonding pads are arranged in a row in the column direction, and The above second bonding pads are arranged in a row in the column direction on one side of the above first bonding pads, forming an array of photodetector elements.

9. In Paragraph 8, The length of the first bonding pad in the row direction is longer than the length of the second bonding pad in the row direction, and An array of light detection elements, wherein the length of the first bonding pad in the column direction is shorter than the length of the second bonding pad in the column direction.

10. In Paragraph 1, An array of photodetector elements, wherein the quenching resistor and the bonding pad, each electrically connected to each of the plurality of photodetector elements, are arranged symmetrically with respect to the central axis of the substrate.

11. In Paragraph 1, An array of photodetectors, wherein each of the plurality of photodetectors comprises a first electrode that is individually configured for the plurality of photodetectors and electrically connected to the quenching resistor, and a second electrode that is common to the plurality of photodetectors.

12. In Paragraph 1, A photodetector array further comprising: a microlens array disposed on the substrate and disposed to cover at least a portion of the quenching resistor electrically connected to each of the plurality of photodetectors.

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