TWI814937B - Laser device - Google Patents

Abstract

The laser device as provided includes a substrate and an epitaxial structure formed thereon. The epitaxial structure is constructed by a first semiconductor structure, an active structure on the first semiconductor, a second semiconductor structure on the active structure, and a current confinement layer located between the active structure and the second semiconductor structure. The laser device also includes a metal layer having an opening passing therethrough, forming the light emitting aperture of the laser device, corresponding to the current-conducting area of the current confinement layer. The laser device also includes a passivation layer partially covering the metal layer, the epitaxial structure and the substrate, and defining the pad area of the laser device. According to the present invention, the angle θ formed between the line passing the center of the opening and the center of the pad area and the longitudinal direction of the laser device is between 0° and 45°.

Description

Laser components

The present disclosure relates to a laser component, and in particular to a small-sized laser component.

Vertical Cavity Surface Emitting Laser (VCSEL) has gradually become a key component in the emerging field due to its low power consumption, high efficiency, fast modulation and other characteristics as well as its wide range of applications. In response to the development trend of device miniaturization, the design of VCSEL also hopes to reduce its size and maintain the same energy efficiency or device performance.

This disclosure proposes a novel design of a laser component that can reduce its packaging volume with the same energy efficiency, increase output within the processable area, and reduce overall process costs.

The present disclosure proposes a laser element, which includes a substrate; an epitaxial structure located on the substrate; the epitaxial structure includes: a first semiconductor structure, an active structure located on the first semiconductor structure, and a second semiconductor structure, on the active structure, and a current confinement layer between the active structure and the second semiconductor structure, the current confinement layer including a current confinement region and a current conduction region surrounded by the current confinement region; a metal layer having a a recess, the position of the recess corresponding to the current conduction area; and a protective layer partially covering the metal layer, the epitaxial structure and the substrate, exposing a first part of the metal layer. Viewed from the top view of the laser element, an axis passing through the center point of the recess and the center point of the first part forms an angle θ with the long side direction of the laser element, where 0°>θ>45°.

The concepts of the present disclosure are explained below with reference to the drawings and example embodiments are used. In the drawings or descriptions, similar or identical parts use the same element symbols; furthermore, the drawings are drawn to facilitate understanding. The thickness and shape of each layer are not the actual size or proportional relationship of the component. It should be noted that components not shown in the drawings or described in the specification may be in a form known to those skilled in the art.

Please refer to Figures 1A to 1C, which are schematic diagrams illustrating the structure of a laser element according to an embodiment of the present disclosure. Figure 1A is a schematic top view of a laser element according to an embodiment of the present disclosure, Figure 1B is a schematic cross-sectional view along line AA' in Figure 1A, and Figure 1C is along line B- in Figure 1A The cross-sectional view shown in B'.

Referring to Figures 1A to 1C, as shown in the figures, the laser element 100 of the present disclosure is a vertical cavity surface emitting laser element (Vertical Cavity Surface Emitting Laser, VCSEL) and includes a substrate 110 and a surface located on the substrate 110 An epitaxial structure 130 on a first surface 120 . The epitaxial structure 130 includes a first semiconductor structure 131 , an active structure 132 located on the first semiconductor structure 131 , and a second semiconductor structure 133 located on the active structure 132 . In the second semiconductor structure 133, a current limiting region 134A and a current conducting region 134B surrounded by the current limiting region 134A are formed. In another embodiment, a current limiting region 134A and a current conducting region 134B are formed in the first semiconductor structure 131 . The current limiting region 134A can be formed through an oxidation process or an ion implant process. In the present disclosure, the first semiconductor structure 131 and the second semiconductor structure 133 include an alternating periodic stacking of a plurality of film layers with different refractive indexes (for example, an AlGaAs layer with a high aluminum content and an AlGaAs layer with a low aluminum content are stacked alternately and periodically). ) to form a Distributed Bragg Reflector (DBR), so that the light emitted by the active structure 132 can be reflected in the two reflectors to form coherent light.

As mentioned above, when the first semiconductor structure 131 and the second semiconductor structure 133 include a plurality of film layers and both include aluminum, the aluminum content of one or more layers in the first semiconductor structure 131 or the second semiconductor structure 133 can be adjusted. Greater than 97% (defined as the current confinement layer 125) and greater than the aluminum content of other film layers of the active structure 132, the first semiconductor structure 131 and the second semiconductor structure 133. Therefore, after the oxidation process is performed, the aluminum content is greater than 97% % of the layer or layers will be oxidized to form the current confinement region 134A (eg, aluminum oxide). Alternatively, hydrogen ions (H ⁺ ), helium ions (He ⁺ ) or argon ions (Ar ⁺ ) are implanted to perform an ion implantation process to form the current limiting region 134A.

The laser element 100 further includes a metal layer 140 formed on the first semiconductor structure 131 and having a recess 150 extending therethrough. The position of the recess 150 corresponds to the current conduction area 134B and is defined as the position of the light-emitting hole of the laser element 100 . The laser element 100 of the present disclosure also includes a protective layer 160 covering the metal layer 140, the epitaxial structure 130 and the substrate 110. The protective layer 160 partially covers the metal layer 140 to expose a first portion 140A of the metal layer 140 . In other words, the metal layer 140 has a first part 140A and a second part 140B. The first part 140A is not covered by the protective layer 160 and is exposed and used for bonding the die bonding area in the subsequent process. The second part 140B is completely covered by the protective layer 160, and the recess 150 is formed in the second part 140B. The protective layer 160 also extends to the recess 150 and covers the sidewalls of the metal layer 140 and directly contacts the second semiconductor structure 133 .

Since the first part 140A is an area not covered by the protective layer 160, designing the shape of the protective layer 160 can define the shape of the first part 140A. The first part 140A can be designed with regular or irregular shapes. Similarly, the recess 150 can also be designed to have a regular or irregular shape. In the present disclosure, viewed from the top view of the laser element 100, the center point C ₁ of the recess 150 and the center point C ₂ of the first part 140A are, for example, the positions of the geometric center (centroid). For example, in the embodiment shown in Figure 1A, the recess 150 and the first part 140A are circular, and their respective center points C ₁ and C ₂ are the circular recess 150 and the first part of the circle respectively. The center position of 140A is the position of the respective centroids of the two circles. The circular recess 150 has a diameter (D) ranging from 10 μm to 20 μm. In one embodiment, there is a relationship between an axis C passing through the center point C ₁ of the recess 150 and the center point C ₂ of the first part 140A and the long side direction of the substrate 110 (ie, the direction of the line X-X' in Figure 1A). It is an angle θ, 0°>θ>45° (for example: 20°, 30°, 40°).

When the angle θ between the center point C ₁ of the recess 150 and the center point C ₂ of the first part 140A and the long side direction of the laser element is 0°, that is, the center point C ₁ of the recess 150 and the first part 140A When the line connecting the center points C ₂ of a part is parallel to the long side direction of the laser element, the distance between the center point C ₁ of the recess 150 and the center point C ₂ of the first part 140A must be less than the distance d. In other words, under this design, the distance between the light-emitting hole of the laser element and the wiring bonding area will be shortened. When subsequent wiring is performed, the light-emitting hole of the laser element is easily damaged by metal lines (such as gold balls) due to process errors. , not shown in the figure) and shielding, affecting the luminous efficiency of the laser element. And when the angle θ between the line connecting the center point C ₁ of the recessed part 150 and the center point C ₂ of the first part 140A and the long side direction of the laser element is greater than (or equal to) 45°, let the angle θ of the recessed part 150 be When the distance between the center point C ₁ and the center point C ₂ of the first part 140A remains the same as d, an angle θ greater than or equal to 45° will increase the size (area) of the entire laser element 100', which is not conducive to small Application of size devices.

In this embodiment, the laser element 100 has a long side L between 130 μm and 160 μm, and a short side W between 90 μm and 120 μm. The distance d between the center point C ₁ of the recess 150 (ie, the light-emitting hole) and the center point C ₂ of the circle 140A of the first part 140A (ie, the wire bonding area) may be between 10 μm and 30 μm. The diameter of the first circular portion 140A is between 60 μm and 80 μm. When the laser element 100 is designed to have the above dimensions (long side or/and short side or/and distance d or/and diameter or/and angle θ), the laser element 100 can have optimal size utilization and reliability. .

According to the present disclosure, the shape of the wire bonding area of the laser component (ie, the first portion 140A of the front metal layer) is not limited to a circle. In order to increase the area of the wire bonding area to facilitate the subsequent packaging process, the shape of the first part of the metal layer, in addition to the circle shown in Figure 1A, can also be designed to further include a plurality of extension parts, such as an extension part, Two extension parts or three extension parts form the first parts 240A, 340A and 440A as shown in Figures 2A, 2B and 2C. As shown in Figure 2A, the first part 240A includes a circular shape 2401 and an extension part 2402. The arc portion of the circle 2401 intersects with its two orthogonal diameters R1 and R2 at four points L1 to L4. The arc portion can be divided into four arc lines A1 to A4, and the circle 2401 can be divided into four parts P1 to P4 ( (respectively, they are the upper right part P1, the upper left part P2, the lower left part P3 and the lower right part P4). The two aforementioned diameters R1 and R2 are parallel to the long side and the short side of the substrate 110 respectively. As shown in the figure, the extension portion 2402 extends outward from the lower right portion P4 or the arc A4 of the circle 2401. What's more, the extension 2402 is defined by the area enclosed by the outer tangent lines E1 and E4 of the circle 2401 at points L1 and L4, and the arc A4. In other words, the boundary of the first part 240A of the metal layer 240 is formed by a three-quarter arc and the outer tangents E1 and E4, and its center point _C2 is the center of the circle 2401. In this embodiment, the length of the outer tangent line E1 and the outer tangent line E4 is the radius of the circle 2401 and is between 30 μm and 40 μm.

As shown in Figure 2B, the first part 340A includes a circular shape 3401 and two extending parts 3402 and 3403. The arc part of the circle 3401 intersects with its two orthogonal diameters R1 and R2 at four points L1~L4. The arc part can be divided into four arcs A1~A4, and the circle 3401 can be divided into four parts P1~P4 ( (respectively, they are the upper right part P1, the upper left part P2, the lower left part P3 and the lower right part P4). The two aforementioned diameters R1 and R2 are parallel to the long side and the short side of the substrate 110 respectively. As shown in the figure, the extension part 3402 extends outward from the lower right part P4 or the arc A4 of the circle 3401, and the extension part 3403 extends outward from the upper right part P1 or the arc A1 of the circle 3401. What's more, the extension 3402 is defined by the area enclosed by the outer tangents E1 and E4 of the circle 3401 at points L1 and L4, and the arc A4, while the extension 3403 is defined by the circle 3401 at point L1. It is defined by the outer tangent line E1 and the outer tangent line E2 at the point L2, and the area surrounding the arc A1. In other words, the boundary of the first part 340A of the metal layer 240 is formed by a half arc and outer tangents E1, E2, and E4, and its center point _C2 is the center of the circle 3401. In this embodiment, the length of the outer tangent line E1 is the diameter of the circle 3401 and is between 60 μm and 80 μm. The lengths of the outer tangent line E2 and the outer tangent line E4 are the radius of the circle 3401 and is between 30 μm and 40 μm.

As shown in Figure 2C, the first part 440A includes a circle 4401 and three extension parts 4402, 4403, and 4404. The arc part of the circle 4401 intersects with its two orthogonal diameters R1 and R2 at four points L1~L4. The arc part can be divided into four arcs A1~A4, and the circle 4401 can be divided into four parts P1~P4 ( (respectively, they are the upper right part P1, the upper left part P2, the lower left part P3 and the lower right part P4). The two aforementioned diameters R1 and R2 are parallel to the long side and the short side of the substrate 110 respectively. As shown in the figure, the extension part 4402 is formed by extending outward from the lower right part P4 or the arc A4 of the circle 4401, and the extension part 4403 is formed by extending outward from the upper right part P1 or the arc A1 of the circle 4401, and the extension part 4404 is formed by extending the lower left part P3 or arc A3 of the circle 4401 outside the circle. What's more, the extension 4402 is defined by the area enclosed by the outer tangent E1 and the outer tangent E4 of the circle 4401 at points L1 and L4, and the arc A4, and the extension 4403 is defined by the circle 4401 at points L1 and L4. The outer tangent E1 and outer tangent E2 at point L2 and the area surrounding arc A1 are defined, and the extension 4404 is defined by the outer tangent E3 and outer tangent E4 and arc A3 of circle 4401 at points L3 and L4. defined by the surrounding area. In other words, the boundary of the first part 440A of the metal layer 440 is composed of a quarter arc and the outer tangent lines E1, E2, E3, and E4, and its center point _C2 is the center of the circle 4401, that is, the center point of the circle 4401. The centroid of the external square is connected, and this design is conducive to maximizing the area of the wire bonding area under the limited size of the laser element. In this embodiment, the length of the outer tangent line E1 and the outer tangent line E4 is the diameter of the circle 4401 and is between 60 μm and 80 μm, and the length of the outer tangent line E2 and the outer tangent line E3 is the radius of the circle 4401 and is between 30 μm and 40 μm.

As explained above, no matter what the shape of the first part of the metal layer (i.e., the wire bonding area of the laser element) is, when the center point of the recess 150 (i.e., the light-emitting hole) and the circular center of the first part (i.e., the wire bonding area) When the angle θ between the line connecting the points and the long side direction of the laser component is less than 45°, it is beneficial to reduce the overall size of the laser component, and can also effectively separate the light-emitting hole and the wire bonding area of the laser component. This prevents metal lines (not shown) from covering the light-emitting hole (ie, the concave portion 150 ) during the subsequent wiring process. In one embodiment, since the shape of the wired metal circuit is spherical, at least part of the boundary of the wired die-bonding area (ie, the first part of the metal layer) includes an arc boundary, and the arc boundary is closest to the light-emitting hole ( That is A2 in Figures 2A~2C).

Since the adhesion between the metal lines and the protective layer 160 is lower than the adhesion between the metal lines and the metal layer 140, when some metal lines are not completely located in the bonding die-bonding area and some metal lines are formed on the protective layer 160, The metal circuit will fall off due to insufficient fixing force, thereby reducing the reliability of the laser component 100 . Therefore, as shown in Figures 2A to 2C, when further considering the fixing force of the metal circuit on the laser element 100, for example, in the laser element 100, the area of the wire bonding area should face the opposite direction of the light-emitting hole (recess 150). The direction extension, that is, the formation of an extension, can effectively reduce the probability that the metal line deviates from the wire bonding area of the laser component (i.e., the first part 440A of the metal layer), thereby improving the probability that the metal line can be completely located in the area of the wire bonding area. probability to improve the fixing force and increase the reliability of laser components.

As explained above, the present disclosure proposes a laser element that further reduces the packaging volume of the laser element by optimizing the relative position arrangement and shape design of the light-emitting hole and the wire bonding area, while still maintaining the same energy. efficiency and luminous efficiency, improving the application flexibility of laser components.

According to the present disclosure, the light-emitting hole of the laser component can be effectively separated from the wire bonding area to prevent the light-emitting hole from being blocked by the metal circuit due to the metal circuit deviating from the wire bonding area during the packaging process. In addition, in the present disclosure, since the area of the wire bonding area is maximized due to its shape design, the adhesion between the metal circuit and the wire bonding area can be effectively improved to prevent the metal circuit from falling off. Therefore, compared with the design of conventional laser components, the laser component of the present disclosure can adapt to different packaging precisions in subsequent packaging processes and has higher applicability.

It should be noted that the foregoing embodiments mentioned in the present disclosure are only used to illustrate the present disclosure and are not used to limit the scope of the present disclosure. Various modifications and changes may be made to this disclosure by those skilled in the art to which this disclosure belongs, without departing from the spirit and scope of this disclosure. The same or similar components in different embodiments, or components represented by the same reference numerals in different embodiments, have the same physical or chemical properties. In addition, under appropriate circumstances, the above-mentioned embodiments of the present disclosure can be combined or replaced with each other, and are not limited to the specific embodiments described above. The connection relationship between specific components and other components described in one embodiment can also be applied to other embodiments, and they all fall within the scope of the patent application of the present disclosure.

100: Laser element 110: Substrate 120: First surface of the substrate 130: Epitaxial structure 131: First semiconductor structure 132: Active structure 133: Second semiconductor structure 134: Current confinement layer 134A: Current confinement region 134B: Current conduction Area 140: Metal layer 140A: First part of metal layer 140B: Second part of metal layer 150: Recess 160: Protective layer 240: Metal layer 240A: First part of metal layer 2401: Circle (first part of metal layer) 2402: Extension (of the first part of the metal layer) 340: Metal layer 340A: First part of the metal layer 3401: Round (of the first part of the metal layer) 3402: Extension (of the first part of the metal layer) 3403: ( Extension 440 of the first part of the metal layer: Metal layer 440A: First part of the metal layer 4401: Circular 4402: Extension (of the first part of the metal layer) 4403: (of the first part of the metal layer) (of the first part) extension 4404: (of the first part of the metal layer) extension C: axis C ₁ : center point of the recess C ₂ : center point of the first part P1: upper right part P2: upper left part P3: lower left part P4: Lower right part R1, R2: Diameter A1~A4: Arc E1~E4: External tangent line L: Long side of laser element W: Short side of laser element

To further understand the features and technical content of the present disclosure, please refer to the following detailed description of the embodiments of the present disclosure and the accompanying drawings. However, the detailed disclosure and accompanying drawings are provided for reference and illustration only and are not intended to limit the disclosure; among them:

Figures 1A to 1C are schematic structural diagrams of a laser element according to an embodiment of the present disclosure. Figure 1A is a schematic top view, Figure 1B is a schematic cross-sectional view along the line A-A’ in Figure 1A, and Figure 1C is a schematic cross-section along the line B-B’ in Figure 1A;

Figures 2A to 2C are schematic top views of laser components according to other embodiments of the present disclosure.

100:Laser components

110:Substrate

120: First surface of substrate

130: Epitaxial structure

140:Metal layer

140A: The first part of the metal layer

150: concave part

440:Metal layer

440A: The first part of the metal layer

4401: Circle (first part of metal layer)

4402: Extension (of the first part of the metal layer)

4403: Extension (of the first part of the metal layer)

4404: Extension (of the first part of the metal layer)

C: Axis

C ₁ : Center point of the concave part

C ₂ : Center point of the first part

E1~E4: outer tangent line

A1~A4: arc

R1, R2: diameter

Claims (10)

A laser component including: a substrate; An epitaxial structure is located on the substrate. The epitaxial structure includes: a first semiconductor structure, an active structure located on the first semiconductor structure, a second semiconductor structure located on the active structure, and a current confinement layer located between the active structure and the second semiconductor structure, the current confinement layer including a current confinement region and a current conduction region surrounded by the current confinement region; A metal layer having a recess extending therethrough, the location of the recess corresponding to the current conduction area; and A protective layer partially covers the metal layer, the epitaxial structure and the substrate, exposing a first part of the metal layer; Wherein, from the top view of the laser element, an axis passing through the center point of the recess and the center point of the first part forms an angle θ with the long side direction of the laser element, where 0°> θ>45°. For example, the laser element described in item 1 of the patent application, wherein the length of the long side of the laser element is in the range of 130 μm to 160 μm, and the length of the short side is in the range of 90 μm to 120 μm. The laser element as described in item 2 of the patent application, wherein, viewed from a top view of the laser element, the distance between the center point of the recess and the center point of the first part is between 10 μm and 30 μm. Scope. In the laser element described in Item 1 of the patent application, the concave portion is circular in shape when viewed from a top view of the laser element, and has a diameter in the range of 10 μm to 20 μm. As for the laser component described in item 1 of the patent application, wherein, viewed from a top view of the laser component, the area of the first part is 30-50% of the area of the laser component. A laser component including: a substrate; An epitaxial structure is located on the substrate, and the epitaxial structure includes: a first semiconductor structure, an active structure located on the first semiconductor structure, a second semiconductor structure located on the active structure, and a current confinement layer located between the active structure and the second semiconductor structure, the current confinement layer including a current confinement region and a current conduction region surrounded by the current confinement region; A metal layer having a recess extending therethrough, the location of the recess corresponding to the current conduction area; and A protective layer partially covers the metal layer, the epitaxial structure and the substrate, exposing a first part of the metal layer; Wherein, viewed from a top view of the laser element, the first part is defined by an arc and a plurality of outer tangents extending from the arc. For example, the laser element described in item 6 of the patent application, wherein the length of the long side of the laser element is in the range of 130 μm to 160 μm, and the length of the short side is in the range of 90 μm to 120 μm. For example, in the laser element described in item 7 of the patent application, the length of the outer tangent line of the first part is between 30 μm and 40 μm or between 60 μm and 80 μm. In the laser element described in Item 6 of the patent application, the concave portion is circular in shape when viewed from a top view of the laser element, and has a diameter in the range of 10 μm to 20 μm. The laser element as described in Item 6 of the patent application, wherein, viewed from a top view of the laser element, the distance between the center point of the recess and the center point of the first part is between 10 μm and 30 μm. Scope.

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