Substrate-on-chip package

Abstract

A base-on-chip package has, for example, a base, a cover layer disposed on the base and intersecting a first direction, a laser element having a light emitting portion at a middle portion in a second direction intersecting the first direction and outputting laser light in a third direction intersecting the first and second directions, and a bonding wire applying a pressing force including a component of a force in an opposite direction to the first direction to the laser element, a residual stress of central compression in the second direction occurring in the cover layer, a first moment of force around a central axis of the light emitting portion in the third direction due to the residual stress, and a second moment of force around the central axis of the light emitting portion due to the pressing force from the bonding wire applied to the laser element canceling each other out.

Description

Technical Field

[0001] This invention relates to chip-on-submount (COP) packages. Background Technology

[0002] Previously, it was known that there were chip-on-a-base packages in which a conductor was provided on a cover layer and a laser element was mounted on the cover layer using solder such as AuSn alloy (for example, Patent Documents 1 and 2).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 5075165

[0006] Patent Document 2: Japanese Patent No. 6928560 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In this type of chip-on-a-base package, the inventors discovered that the laser output from the laser element may be polarized and rotated (shifted) depending on the mounting position of the laser element relative to the base or the mounting position of the bonding line relative to the laser element, making it difficult to obtain the desired optical characteristics.

[0009] Therefore, one of the objectives of this invention is to obtain, for example, a novel and improved chip-on-a-base package that can suppress polarization wave rotation caused by the mounting of constituent components.

[0010] Solution for solving the problem

[0011] The chip-on-a-base package of the present invention includes, for example: a base having a first surface facing a first direction; a cover layer mounted on the first surface, extending in a manner intersecting the first direction, and having a second surface facing the first direction; a laser element mounted on the second surface, having a third surface facing the first direction, and a light-emitting portion located at the middle portion of a second direction intersecting the first direction and extending along a third direction intersecting both the first and second directions and emitting laser light along the third direction; and a bonding line mounted on the third surface, applying a pressing force to the laser element including a component force in the opposite direction to the first direction, generating residual stress of central compression in the second direction toward the cover layer, wherein a first torque about the central axis of the light-emitting portion along the third direction generated by the external force acting on the laser element from the cover layer due to the residual stress cancels out the second torque about the central axis of the light-emitting portion generated by the pressing force acting on the laser element from the bonding line.

[0012] Additionally, the chip package on the substrate of the present invention includes, for example: a substrate having a first surface facing a first direction; a cover layer mounted on the first surface, extending in a manner intersecting the first direction, and having a second surface facing the first direction; a laser element mounted on the second surface, having a third surface facing the first direction, and a light-emitting portion located at the middle portion of a second direction intersecting the first direction and extending along a third direction intersecting both the first and second directions and emitting laser light along that third direction; and a bonding line mounted on the third surface, applying a pressing force to the laser element that includes a component force in the opposite direction to the first direction, generating residual stress of central compression in the second direction toward the cover layer, such that the sum of a first torque about the central axis of the light-emitting portion along the third direction generated by the external force acting on the laser element from the cover layer due to the residual stress and a second torque about the central axis of the light-emitting portion generated by the pressing force acting on the laser element from the bonding line is approximately 0.

[0013] In the chip package on the base, the light-emitting part may be located at an end of the laser element that is closer to the center in the first direction than to the end in the opposite direction of the first direction, and the laser element has a protrusion that is aligned with the light-emitting part in the first direction and protrudes in the opposite direction of the first direction.

[0014] In the chip package on the base, the width of the cover layer in the second direction may be narrower than the width of the base in the second direction, but wider than the width of the laser element in the second direction.

[0015] In the chip package on the substrate, the thickness of the laser element in the first direction may be less than 1 / 3 of the thickness of the substrate in the first direction.

[0016] In the chip package on the base, the base may be made of aluminum nitride and the cover layer may be made of copper-based material.

[0017] In the chip package on the base, the light-emitting part may be located at a position offset from the center of the second direction relative to the cover layer towards one of the second direction and the opposite direction of the second direction, namely the fourth direction, and the pressing position of the bonding line on the third surface may be located at a position offset from the light-emitting part towards the opposite direction of the fourth direction.

[0018] In the chip package on the base, the center of the laser element in the second direction may be located at a position offset from the center of the cover layer in the second direction to the side opposite to the pressing position.

[0019] In the chip package on the base, the light-emitting part may also be located in the center in the second direction relative to the laser element, on the side opposite to the pressing position.

[0020] In the chip package on the base, the bonding line pressing position on the third surface, the position of the light-emitting part, and the center of the cover layer in the second direction can also be arranged along the first direction.

[0021] In the chip package on the base, multiple bonding lines may be installed on the third surface as bonding lines, and the pressing positions of the multiple bonding lines on the third surface are arranged along the first direction at the center of gravity in the second direction, the position of the light-emitting part, and the center of the cover layer in the second direction.

[0022] Additionally, the chip package on the substrate of the present invention includes, for example: a substrate having a first surface facing a first direction; a cover layer mounted on the first surface, extending in a manner intersecting the first direction, and having a second surface facing the first direction; a laser element mounted on the second surface, having a third surface facing the first direction, and a light-emitting portion located at the middle portion of a second direction intersecting the first direction and extending along a third direction intersecting both the first and second directions and emitting laser light along that third direction; and a bonding line mounted on the third surface, applying a pressing force to the laser element including a component force in the opposite direction to the first direction, wherein the light-emitting portion is located at a position offset from the center of the second direction relative to the cover layer toward one of the second direction and the opposite direction of the second direction, i.e., a fourth direction, and the pressing position of the bonding line on the third surface is located at a position offset from the light-emitting portion toward the opposite direction of the fourth direction.

[0023] Additionally, the chip package on the base of the present invention includes, for example: a base having a first surface facing a first direction; a cover layer mounted on the first surface, extending in a manner intersecting the first direction, and having a second surface facing the first direction; a laser element mounted on the second surface, having a third surface facing the first direction, and a light-emitting portion located at the middle portion of a second direction intersecting the first direction and extending along a third direction intersecting both the first and second directions and emitting laser light along that third direction; and a bonding line mounted on the third surface, applying a pressing force to the laser element including a component force in the opposite direction to the first direction, wherein the pressing position of the bonding line on the third surface is at the center of gravity in the second direction, and the light-emitting portion and the center of the cover layer in the second direction are arranged along the first direction.

[0024] Invention Effects

[0025] According to the present invention, a novel improved chip-on-a-base package can be obtained, for example, which can suppress the rotation of polarized waves corresponding to the mounting position of the constituent components. Attached Figure Description

[0026] Figure 1 This is an exemplary and schematic front view of the chip package on the base according to the first embodiment.

[0027] Figure 2 This is an exemplary and schematic front view of the chip package on the base according to the second embodiment.

[0028] Figure 3 This is an exemplary and schematic front view of the chip package on the base according to the third embodiment.

[0029] Figure 4 This is an exemplary and schematic front view of the chip package on the base according to the fourth embodiment.

[0030] Figure 5 This is an exemplary and schematic front view of the chip package on the base according to the fifth embodiment. Detailed Implementation

[0031] Hereinafter, several exemplary embodiments of the present invention are disclosed. The structure of the embodiments shown below, as well as the functions and results (effects) that can be achieved according to the structure, are examples. The present invention can also be implemented with structures other than those disclosed in the following embodiments. In addition, according to the present invention, at least one of various effects (including derived effects) obtained by the structure can be obtained.

[0032] The various embodiments shown below have the same structure. Therefore, based on the structure of each embodiment, the same functions and effects can be obtained. Furthermore, in the following descriptions, these same structures are sometimes labeled with the same reference numerals, and repeated descriptions are omitted.

[0033] In addition, in each diagram, arrow X represents the X direction, arrow Y represents the Y direction, and arrow Z represents the Z direction. The X, Y, and Z directions intersect and are orthogonal. The X direction is the direction in which the laser light is emitted from the laser element, and it is also the direction of the long side of the laser element. The Y direction is the width direction of the laser element. Furthermore, the Z direction is the stacking direction of the base, cladding layer, and laser element, and is also known as the thickness direction.

[0034] In addition, the figures are schematic illustrations, and there may be cases where the dimensions in the figures differ from the actual dimensions of the objects.

[0035] [First Implementation Method]

[0036] Figure 1 This is a front view of the chip package 100A (100) on the base of the first embodiment, viewed in the opposite direction to the X direction. (Example) Figure 1 As shown, the chip package 100A on the substrate includes a substrate 10, a cover layer 20, a semiconductor laser chip 30, and bonding lines 50. The semiconductor laser chip 30 is an example of a laser element.

[0037] The base 10 extends with a substantially constant thickness in the Z direction in a manner intersecting and orthogonal to the Z direction. The base 10 has a surface 10a and a surface 10b opposite to surface 10a. Surface 10a faces the opposite direction to the Z direction and intersects and orthogonal to the Z direction. Surface 10b faces the Z direction and intersects and orthogonal to the Z direction. Surface 10a is also referred to as the back surface, and surface 10b is also referred to as the front surface. Surface 10b is an example of a first surface. The Z direction is an example of a first direction.

[0038] The thickness of the base 10 is, for example, about 0.3 to 1.0 mm. Furthermore, the material of the base 10 may contain at least one of, for example, aluminum nitride (AlN), aluminum oxide (Al2O3), beryllium oxide (BeO), boron nitride (BN), diamond, silicon nitride (Si3N4), silicon carbide (SiC), silicon dioxide (SiO2), and zirconium oxide (ZrO2). The coefficients of thermal expansion of aluminum nitride, silicon nitride, and silicon carbide are 4.5 × 10⁻⁶. -6 [1 / K], 2.8 × 10 -6 [1 / K], 3.7 × 10 -6 [1 / K].

[0039] A cover layer 20 is mounted on surface 10b of base 10. Cover layer 20 extends with a substantially constant thickness in the Z direction in a manner intersecting and orthogonal to the Z direction. Cover layer 20 has a surface 20a and a surface 20b opposite to surface 20a. Surface 20a faces the opposite direction to the Z direction and intersects and is orthogonal to the Z direction. Surface 20b faces the Z direction and intersects and is orthogonal to the Z direction. Surface 20a is also referred to as the back surface, and surface 20b is also referred to as the front surface. Surface 20b is an example of a second surface.

[0040] The thickness of the capping layer 20 is, for example, about 20 to 200 μm. The capping layer 20 is made of, for example, a copper-based material. Furthermore, copper has a coefficient of thermal expansion of 17 × 10⁻⁶. -6 [1 / K]. The coefficient of thermal expansion of the cover layer 20 is greater than that of the base 10. The cover layer 20 may also be referred to as the intermediate layer or cover component, intermediate component.

[0041] Additionally, another cover layer (not shown), different from the cover layer 20, is also provided on surface 10b of the base 10. Both the cover layer 20 and this other cover layer are conductors made of the aforementioned material. The cover layer 20 and the other cover layer are separated by grooves (spacers) and are electrically insulated. The cover layer 20 and the other cover layer have a multilayer film made of the aforementioned copper-based material. It should be noted that there are also cases where the base 10 in this embodiment is referred to as a substrate, and the substrate containing the cover layer (the base 10 in this embodiment) is referred to as a base.

[0042] A semiconductor laser chip 30 is mounted on surface 20b of the cover layer 20 via a conductive bonding material 40. The bonding material 40 is, for example, AuSn solder. The bonding material 40 is heated to a temperature above its melting point during a reflow soldering process and then cured by being cooled to room temperature, thereby bonding the cover layer 20 to the semiconductor laser chip 30.

[0043] The semiconductor laser chip 30 extends with a substantially constant thickness in the Z direction in a manner that intersects and orthogonally to the Z direction. The semiconductor laser chip 30 has a surface 30a and a surface 30b opposite to the surface 30a. Surface 30a faces the opposite direction to the Z direction and intersects and orthogonally to the Z direction. Surface 30b faces the Z direction and intersects and orthogonally to the Z direction.

[0044] Furthermore, the semiconductor laser chip 30 has a light-emitting portion 31 that outputs laser light in the X direction. The light-emitting portion 31 is located in the middle portion of the semiconductor laser chip 30 in the Y direction, specifically at the center Cc in the Y direction in this embodiment, and extends in the X direction. Additionally, the light-emitting portion 31 is located closer to surface 30a than the center of the semiconductor laser chip 30 in the Z direction; specifically, the light-emitting portion 31 is located near surface 30a. Surface 30a is also referred to as the surface, and surface 30b is also referred to as the back surface. Surface 30b is an example of a third surface. The light-emitting portion 31 is also referred to as the active layer. Furthermore, in this embodiment, the semiconductor laser chip 30 is mounted with the junction facing downwards. It should be noted that the middle portion in the Y direction of the semiconductor laser chip 30 refers to the portion between the end in the Y direction and the end in the opposite direction of the Y direction in the semiconductor laser chip 30. The Y direction is an example of a second direction, and the X direction is an example of a third direction.

[0045] The capping layer 20 is electrically connected to an electrode (e.g., a p-type electrode, not shown) disposed on surface 30a of the semiconductor laser chip 30 via a bonding material 40. Additionally, another layer on surface 10b is electrically connected to an electrode (e.g., an n-type electrode, not shown) disposed on surface 30b of the semiconductor laser chip 30 via a bonding line 50. The bonding line 50 is bonded and electrically connected to the electrode disposed on surface 30b via a bonding material such as AuSn solder.

[0046] The semiconductor laser chip 30 outputs laser light of a wavelength corresponding to its structure or material. The thickness of the semiconductor laser chip 30 is, for example, approximately 0.1 mm. Furthermore, the main components of the semiconductor laser chip 30 are, for example, gallium arsenide (GaAs) or indium phosphide (InP). The coefficient of thermal expansion of gallium arsenide and indium phosphide is 5.9 × 10⁻⁶. -6 [1 / K], 4.5×10 -6 [1 / K].

[0047] In the chip package 100A (100) on the substrate of the above structure, the coefficient of thermal expansion of the cover layer 20 is greater than that of the substrate 10. During the cooling process of the reflow soldering of the bonding material 40, the cover layer 20 shrinks significantly compared to the substrate 10. Therefore, in Figure 1 From the perspective of the main view when observing the chip package 100 on the base in the opposite direction of the X direction, a residual stress Sc is generated in the cover layer 20, which compresses the center Cm in the Y direction.

[0048] The residual stress Sc acts as an external force on surface 30a of the semiconductor laser chip 30 via surface 20b and bonding material 40. Due to this external force, a torque M1 acts on the light-emitting portion 31, extending in the X direction around its central axis Ax. Figure 1 In the example, the position P1 of the light-emitting part 31 is located offset in the opposite direction from the center Cm in the Y direction of the cover layer 20. Here, in the cover layer 20, it is located further back in the Y direction than the center Cm (in Figure 1 In the region (left side of the center), residual stress is generated towards the center Cm and compresses in the Y direction. Therefore, in the surface 30a of the semiconductor laser chip 30, in the region near the light-emitting portion 31 and relative to it in the Z direction (in the left side of the center), residual stress is generated, compressing in the Y direction. Figure 1 The part located in the middle (below) acts in the Y direction (in) Figure 1 The external force (from the right) acts on the light-emitting part 31 due to this external force. Figure 1 The torque M1 is in the counterclockwise direction. Torque M1 is an example of the first torque. Additionally, in... Figure 1 In the example, the opposite direction of the Y direction is an example of the fourth direction. It should be noted that in the overlay layer 20, the direction forward in the Y direction from the center Cm (in...) Figure 1 The part (right side) generates residual stress that compresses in the opposite direction to the center Cm and the Y direction.

[0049] On the other hand, in the chip package 100A (100) on the base of the above-described structure, a pressing force Fw acts from the bonding line 50 toward the cover layer 20 and the base 10, pressing the semiconductor laser chip 30. The pressing force Fw includes the opposite direction toward the Z direction (in Figure 1 The force component is located in the middle (below).

[0050] Due to the pressing force Fw, a torque M2 exists on the light-emitting part 31 about its central axis Ax. Figure 1In the example, the pressing position of the bonding line 50 relative to the surface 30b of the semiconductor laser chip 30, that is, the connection position Pw between the bonding line 50 and the surface 30b, is located at position P1 (in this embodiment, the same position as the center Cc in the Y direction of the semiconductor laser chip 30) in the Y direction from the light-emitting part 31 (central axis Ax) towards the Y direction (in Figure 1 The position is offset by an offset amount dw (to the right). In this case, due to the pressing force Fw, the light-emitting part 31 is affected. Figure 1 The torque M2 in the clockwise direction. Torque M2 is an example of the second torque. Additionally, in Figure 1 In the example, the Y direction is the opposite direction of the fourth direction.

[0051] The inventors discovered that the polarization angle of the laser output from the semiconductor laser chip 30 varies depending on the connection position Pw of the bonding line 50 in the Y direction. Specifically, the inventors fabricated multiple semiconductor laser chips 30 with different connection positions Pw in the Y direction and investigated the relationship between the offset dw of the connection position Pw relative to the center Cc of the semiconductor laser chip 30 in the Y direction and the polarization rotation angle (rotation offset from the desired state) of the laser output from the semiconductor laser chip 30. It should be noted that the offset dw is a manufacturing target value, including tolerance range. Furthermore, for the reference numerals of the offset dw, a positive (+) sign indicates that the connection position Pw is offset in the Y direction relative to the center Cc, and a negative (-) sign indicates that it is offset in the opposite direction to the Y direction. Figure 1 In the example, the central Cc in the Y direction of the semiconductor laser chip 30 is the position P1 in the Y direction of the light-emitting part 31 (central axis Ax). The experimental results are shown below.

[0052] (Experimental Results)

[0053] With dw = +30 μm, the polarization rotation angle is 0–15 degrees (evaluation: optimal).

[0054] With dw = +15 μm, the polarization rotation angle is -10 to 0 degrees (evaluation: optimal).

[0055] With dw = 0 [μm], the polarization wave rotation angle is -20 to -5 [deg] (evaluation: good).

[0056] With dw = -15 μm, the polarization rotation angle is -30 to -10 degrees (Grade: Pass).

[0057] With dw = -30 μm, the polarization rotation angle is -50 to -35 degrees (evaluation: failing).

[0058] According to the experimental results, the larger the offset dw, the larger the polarization wave rotation angle. Furthermore, it was found that the polarization wave rotation angle is not minimum when dw = 0, but minimum when dw = +15 to +30. According to the inventors' analysis, this is because the position Pl of the light-emitting part 31 in the Y direction is offset in the opposite direction to the center Cm of the covering layer 20 in the Y direction (the offset relative to the center Cm of position Pl: dc, see reference...). Figure 1 ).

[0059] The above presumptions are as follows: Figure 1 As shown in the example, by constructing the chip package 100A on the base in such a way that the torque M1 generated by the residual stress Sc and the torque M2 generated by the pressing force Fw cancel each other out, a semiconductor laser chip 30 with small polarization wave rotation and good optical characteristics with respect to the desired characteristics can be obtained.

[0060] Furthermore, in this embodiment, as described above, the position Pl of the light-emitting part 31 is located at a position offset in the opposite direction (fourth direction) of the center Cm in the Y direction relative to the cover layer 20, while the connection position Pw of the bonding line 50 is located at a position offset in the Y direction (opposite direction) relative to the position Pl of the light-emitting part 31, thereby suppressing the polarization wave rotation relative to the desired characteristics.

[0061] Furthermore, in this embodiment, the light-emitting part 31 (central axis Ax) is located at the center Cc in the Y direction of the semiconductor laser chip 30. Therefore, the center Cc is offset to the side opposite to the connection position Pw relative to the center Cm in the Y direction of the cover layer 20, thereby suppressing the polarization wave rotation relative to the desired characteristics.

[0062] Furthermore, according to the inventors' research, it has been found that the reduction in polarization wave rotation angle brought about by such a structure can be achieved when the width Wm of the cover layer 20 in the Y direction is narrower than the width Ws of the base 10 in the Y direction and wider than the width Wc of the semiconductor laser chip 30. This is particularly preferable when the difference between width Wm and width Ws (Ws-Wm) is less than or equal to half the width Ws, and more preferably when the difference is less than or equal to one-third of the width Ws. Additionally, it has been found that the thickness Tc of the semiconductor laser chip 30 in the Z direction is preferably less than or equal to one-third of the thickness Ts of the base 10 in the Z direction.

[0063] [Second Implementation]

[0064] Figure 2 This is a front view of the chip package 100B (100) on the base of the second embodiment, viewed in the opposite direction to the X direction.

[0065] The chip package 100B on the base in this embodiment has the same structure as in the first embodiment described above. However, in this embodiment, the position P1 of the light-emitting portion 31 in the Y direction within the semiconductor laser chip 30B differs from that in the first embodiment. That is, in this embodiment, the light-emitting portion 31 (central axis Ax) in the semiconductor laser chip 30B is located at a position offset from the center Cc in the Y direction of the semiconductor laser chip 30B to the side opposite to the connection position Pw. In this case, by configuring the center Cc in the Y direction of the semiconductor laser chip 30B to overlap with the center Cm in the Y direction of the cover layer 20, the same layout as in the first embodiment can be obtained. That is, according to this embodiment, it is easier to obtain a state in which the position P1 of the light-emitting portion 31 is offset from the center Cm in the Y direction of the cover layer 20 in the opposite direction (fourth direction) and the connection position Pw of the bonding line 50 is offset from the position P1 of the light-emitting portion 31 in the Y direction (opposite direction of the fourth direction), i.e., a state in which the torque M1 and the torque M2 cancel each other out. According to this embodiment, similar to the first embodiment described above, it is also possible to suppress polarization wave rotation relative to the desired characteristics.

[0066] [Third Implementation Method]

[0067] Figure 3 This is a front view of the chip package 100C(100) on the base of the third embodiment, viewed in the opposite direction to the X direction.

[0068] The chip package 100C on the base in this embodiment has the same structure as in the first embodiment described above. However, in this embodiment, the position P1 of the light-emitting portion 31 (central axis Ax), the connection position Pw between the bonding line 50 and the surface 30b, and the position of the center Cm in the Y direction of the cover layer 20 are arranged along the Z direction. In other words, the position P1, the connection position Pw, and the center Cm are located at the same position in the Y direction. In this case, no torque M1 is generated around the central axis Ax due to the external force based on the residual stress Sc, and since the length of the torque arm is approximately 0, no torque M2 is generated around the central axis Ax due to the pressing force Fw acting from the connection position Pw, so the sum of torque M1 and torque M2 is approximately 0. Therefore, according to this embodiment, as in the other embodiments described above, polarization wave rotation relative to the desired characteristics can also be suppressed. It should be noted that in this embodiment, the connection position Pw can also be referred to as the center of gravity position where the pressing force Fw acts.

[0069] [Fourth Implementation Method]

[0070] Figure 4This is a front view of the chip package 100D(100) on the base of the fourth embodiment, viewed in the opposite direction to the X direction.

[0071] The chip package 100D on the base in this embodiment has the same structure as in the first embodiment described above. However, in this embodiment, multiple bonding lines 50 are symmetrically mounted on the surface 30b of the semiconductor laser chip 30 with the center Cc in the Y direction as the center. The centroid position of the multiple connection positions Pw in the Y direction is set as Pwc. Furthermore, in this embodiment, the position P1 of the light-emitting part 31 (central axis Ax), the centroid position Pwc, and the position of the center Cm of the cover layer 20 in the Y direction are arranged along the Z direction. In other words, the position P1, the centroid position Pwc, and the center Cm are located at the same position in the Y direction. In this case, no torque M1 is generated around the central axis Ax due to the external force based on the residual stress Sc, and since the length of the torque arm is approximately 0, no torque M2 is generated around the central axis Ax due to the pressing force Fw (resultant force) acting from the centroid position Pwc, so the sum of torque M1 and torque M2 is approximately 0. Therefore, according to this embodiment, similar to the other embodiments described above, it is also possible to suppress polarization wave rotation relative to the desired characteristics.

[0072] [Fifth Implementation Method]

[0073] Figure 5 This is a front view of the chip package 100E(100) on the base of the fifth embodiment, viewed in the opposite direction to the X direction.

[0074] The chip package 100E on the base in this embodiment has the same structure as in the first embodiment described above. However, in this embodiment, the semiconductor laser chip 30E is a so-called ridge-type chip with a protrusion 30c protruding from the surface 30a near the light-emitting portion 31. In this case, the light-emitting portion 31 is located at the end of the semiconductor laser chip 30E in the opposite direction to the Z-direction, i.e., the surface 30a, closer to the center Cz in the Z-direction, and the protrusion 30c and the light-emitting portion 31 are arranged along the Z-direction. According to the inventors' research, it has been found that the same effect can be obtained in such a ridge-type semiconductor laser chip 30E by having the same structure as in the other embodiments described above.

[0075] The above embodiments of the present invention have been illustrated, but these embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other ways, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of various structures, shapes, etc. (construction, type, orientation, model, size, length, width, thickness, height, quantity, configuration, position, material, etc.) can be appropriately modified for implementation.

[0076] For example, the direction of the central offset of each component or part relative to the cover layer in the second direction is not limited to the above embodiment, and may be the opposite of the above embodiment.

[0077] Industrial applicability

[0078] This invention can be used in chip packages on a substrate.

[0079] Explanation of reference numerals in the attached figures

[0080] 100, 100A~100E…Chip package on substrate; 10…Substrate; 10a…Surface; 10b…Surface (first surface); 20…Cover layer; 20a…Surface; 20b…Surface (second surface); 30, 30B, 30E…Semiconductor laser chip (laser element); 30a…Surface; 30b…Surface (third surface); 30c…Protrusion; 31…Light-emitting part; 40…Bonding material; 50…Bonding line; Ax…Central axis; Cc…Center; Cm…Center; Cz…Center; dc…Offset; dw…Offset; Fw…Pressing force; M1…Torque (first torque); M2…Torque (second torque); Pl…Position; Pw…Connection position (pressing position); Pwc…Center of gravity position; Sc…Residual stress; Tc…Thickness; Ts…Thickness; Wc…Width; Wm…Width; Ws…Width; X…Direction (third direction); Y…Direction (opposite to the second and fourth directions); Z…Direction (first direction).

Claims

1. A chip-on-a-base package, comprising: A base having a first face facing a first direction; A cover layer is mounted on the first surface, extends in a manner intersecting the first direction, and has a second surface facing the first direction; A laser element is mounted on the second surface and has a third surface facing the first direction, and a light-emitting portion located in the middle of a second direction intersecting the first direction and extending along a third direction intersecting the first and second directions and emitting laser light along the third direction. as well as A bonding line, mounted on the third surface, applies a pressing force to the laser element, comprising a force component in the opposite direction to the first direction. Residual compressive stress is generated in the cover layer in the second direction toward the cover layer. The first torque about the central axis of the light-emitting portion along the third direction, generated by the external force acting on the laser element from the cover layer due to the residual stress, cancels out the second torque about the central axis of the light-emitting portion generated by the pressing force acting on the laser element from the bonding line.

2. A chip-on-a-base package, comprising: A base having a first face facing a first direction; A cover layer is mounted on the first surface, extends in a manner intersecting the first direction, and has a second surface facing the first direction; A laser element is mounted on the second surface and has a third surface facing the first direction, and a light-emitting portion located in the middle of a second direction intersecting the first direction and extending along a third direction intersecting the first and second directions and emitting laser light along the third direction. as well as A bonding line, mounted on the third surface, applies a pressing force to the laser element, comprising a force component in the opposite direction to the first direction. Residual compressive stress is generated in the cover layer in the second direction toward the cover layer. The sum of the first torque about the central axis of the light-emitting portion along the third direction, generated by the external force acting on the laser element from the cover layer due to the residual stress, and the second torque about the central axis of the light-emitting portion, generated by the pressing force acting on the laser element from the bonding line, is approximately 0.

3. The chip-on-a-base package according to claim 1 or 2, wherein, The light-emitting part is located at a position on the laser element that is closer to the end in the opposite direction to the first direction than the center in the first direction. The laser element has a protrusion that is aligned with the light-emitting portion along the first direction and protrudes in the opposite direction to the first direction.

4. The chip-on-a-base package according to claim 1 or 2, wherein, The width of the cover layer in the second direction is narrower than the width of the base in the second direction, but wider than the width of the laser element in the second direction.

5. The chip-on-a-base package according to claim 1 or 2, wherein, The thickness of the laser element in the first direction is less than 1 / 3 of the thickness of the base in the first direction.

6. The chip-on-a-base package according to claim 1 or 2, wherein, The base is made of aluminum nitride. The covering layer is made of copper-based materials.

7. The chip-on-a-base package according to claim 1 or 2, wherein, The light-emitting part is located at a position offset from the center of the second direction relative to the cover layer, towards one of the second direction and the opposite direction of the second direction, namely the fourth direction. The pressing position of the bonding line on the third surface is located at a position offset in the opposite direction to the fourth direction relative to the light-emitting part.

8. The chip package on the base according to claim 7, wherein, The center of the laser element in the second direction is located at a position offset from the center of the cover layer in the second direction to the side opposite to the pressing position.

9. The chip package on the base according to claim 7, wherein, The light-emitting part is located in the center in the second direction relative to the laser element, on the side opposite to the pressing position.

10. The chip-on-a-base package according to claim 1 or 2, wherein, The bonding line is positioned at the pressing point of the third surface, the position of the light-emitting part is such that the center of the cover layer in the second direction is arranged along the first direction.

11. The chip-on-a-base package according to claim 1 or 2, wherein, Multiple bonding lines are installed on the third surface to serve as bonding lines. The multiple bonding lines are arranged along the first direction at the center of gravity of the pressing position of the third surface in the second direction, the position of the light-emitting part, and the center of the cover layer in the second direction.

12. A chip-on-a-base package, comprising: A base having a first face facing a first direction; A cover layer is mounted on the first surface, extends in a manner intersecting the first direction, and has a second surface facing the first direction; A laser element is mounted on the second surface and has a third surface facing the first direction, and a light-emitting portion located in the middle of a second direction intersecting the first direction and extending along a third direction intersecting the first and second directions and emitting laser light along the third direction. as well as A bonding line, mounted on the third surface, applies a pressing force to the laser element, comprising a force component in the opposite direction to the first direction. The light-emitting part is located at a position offset from the center of the second direction relative to the cover layer, towards one of the second direction and the opposite direction of the second direction, namely the fourth direction. The pressing position of the bonding line on the third surface is located at a position offset in the opposite direction to the fourth direction relative to the light-emitting part.

13. A chip-on-a-base package, comprising: A base having a first face facing a first direction; A cover layer is mounted on the first surface, extends in a manner intersecting the first direction, and has a second surface facing the first direction; A laser element is mounted on the second surface and has a third surface facing the first direction, and a light-emitting portion located in the middle of a second direction intersecting the first direction and extending along a third direction intersecting the first and second directions and emitting laser light along the third direction. as well as A bonding line, mounted on the third surface, applies a pressing force to the laser element, comprising a force component in the opposite direction to the first direction. The center of gravity of the pressing position of the bonding line on the third surface in the second direction, the light-emitting part, and the center of the cover layer in the second direction are arranged along the first direction.

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