Electronic component

Abstract

This electronic component includes: a base material which has a main surface; an insulating layer which is disposed on the main surface of the base material and has a level difference part; a conductive layer which is formed on the level difference part of the insulating layer; and a barrier layer which covers the conductive layer. A surface of the conductive layer, which corresponds to the level difference part, has an inclination.

Description

Electronic Components

[0001] The present disclosure relates to electronic components.

[0002] In the manufacturing process of semiconductors and electronic components, when covering a step formed in a substrate, a seam may occur near the sidewall of the step. There is a concern that etching solutions used in subsequent processes may penetrate through the seam, resulting in a decrease in the reliability of elements (e.g., wiring layers and gate electrodes) that make up the step. In response to this issue, Patent Document 1 discloses a technology in which an insulating layer covering a wiring layer has a multi-layer structure, thereby making the seam discontinuous. Furthermore, Patent Document 2 discloses an electronic component in which a barrier metal layer is formed on an electrode layer.

[0003] International Publication No. 2017 / 183390 Japanese Patent Application Laid-Open No. 2013-80978

[0004] However, Patent Document 1 does not prevent the occurrence of seams themselves, and defects such as film formation with voids (gaps) occurring in the interlayer areas where seams are discontinuous can occur. In this case, the seams may become connected, allowing chemicals, moisture, unwanted gases, etc. to penetrate, which can lead to a decrease in reliability. Therefore, there is a need to improve the reliability of electronic components by preventing the occurrence of seams and the penetration of etching solutions, etc.

[0005] An object of the present disclosure is to provide an electronic component that can improve reliability.

[0006] The electronic component according to the present disclosure includes a substrate having a main surface, an insulating layer disposed on the main surface of the substrate and having a stepped portion, a conductive layer formed on the insulating layer in the stepped portion, and a barrier layer covering the conductive layer, and the surface of the conductive layer corresponding to the stepped portion has an inclination.

[0007] The electronic component according to the present disclosure has a conductive layer formed in a step portion on an insulating layer. The film growth rate of the conductive layer is slower in the step portion than on the bottom surface of the step portion, making seams more likely to occur. In contrast, in the present disclosure, the surface of the conductive layer corresponding to the step portion is inclined. This promotes continuous growth of the conductive layer film in the step portion, thereby suppressing the occurrence of seams or reducing the seam size. By suppressing seams in the conductive layer, the formation of seams in the barrier layer can be suppressed. Furthermore, because the barrier layer covers the conductive layer, even if a seam occurs in the conductive layer, penetration of the etching solution into the seam can be suppressed. As a result, the reliability of the electronic component can be improved.

[0008] The side surface of the barrier layer may be inclined. For example, if the side surface of the barrier layer is not inclined, voids may be formed between the barrier layer and the conductive layer at the base of the electrode pad during the formation of the barrier layer. The barrier layer may then peel off from these voids, potentially allowing etching solutions and other substances to get into the conductive layer. In contrast, if the side surface of the barrier layer is inclined, the formation of voids is suppressed, the barrier layer is less likely to peel off, and the intrusion of etching solutions and other substances can be more reliably prevented.

[0009] The inclination angle of the surface corresponding to the step portion may be 110° or more and 140° or less. An inclination angle of 110° or more can effectively suppress the occurrence of seams. Furthermore, an inclination angle of 140° or less can prevent the width of the electrode pad from becoming too wide.

[0010] The conductive layer may contain elements other than Au. Although Au is stable against the etching solution, the presence of other elements in the conductive layer may cause the formed seam to corrode and expand due to the etching solution, increasing the risk of reduced reliability of the device. Therefore, the effect of the present disclosure in suppressing the seam becomes more pronounced.

[0011] The substrate may include GaN. ２ O ２ A chemical solution containing this H is often used. ２ O ２ oxidizes GaN and ２O ３ When GaN is used as the substrate, the conductive layer may be corroded and H ２ O ２ When the GaN layer penetrates into the substrate, Ga is formed between the GaN and the conductive layer. ２ O ３ Therefore, the present disclosure can be more effective when the substrate contains GaN.

[0012] The barrier layer may contain at least one of Ni, Ta, Ti, W, Mo, Cr, Zn, In, Nb, Sn, and C. In this case, the corrosion resistance of the barrier layer against the etching solution can be improved, and therefore, corrosion of the conductive layer due to damage caused by corrosion of the barrier layer can be suppressed.

[0013] The electronic component may further include a thin film formed on the barrier layer. In this case, even if a defect such as a hole exists in the barrier layer, the thin film can cover the defect. Therefore, corrosion of the conductive layer by the etching solution can be more reliably suppressed.

[0014] According to the present disclosure, it is possible to provide an electrode pad and an electronic component that can improve reliability.

[0015] FIG. 1 is a schematic cross-sectional view showing an electrode pad and an electronic component according to an embodiment of the present disclosure. FIG. 1 is a schematic cross-sectional view for explaining actions and effects. FIG. 2 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example. FIG. 3 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example. FIG. 4 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example. FIG. 5 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example. FIG. 6 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example.

[0016] The configurations of an electrode pad and an electronic component according to an embodiment will be described with reference to Fig. 1. The electronic component 1 according to the embodiment includes a substrate 10, an insulating layer 20, and an electrode pad 30. The electronic component 1 is, for example, a semiconductor element, such as an LED element or a semiconductor laser element.

[0017] The substrate 10 is a flat plate-shaped member. The substrate 10 has a flat main surface 10a. The substrate 10 may contain GaN. Alternatively, the substrate 10 may contain GaAs, GaP, AlGaInP, InGaN, Si, or the like.

[0018] The insulating layer 20 is disposed on the main surface 10a of the substrate 10 so as to cover the main surface 10a. The insulating layer 20 is a so-called passive film (passivation film). The insulating layer 20 has a flat main surface 20a. The insulating layer 20 is composed of an oxide or nitride containing at least one element selected from the group consisting of Si, Al, Zr, Mg, Ta, Ti, and Y, or a resin. For example, the insulating layer 20 may contain at least one of silicon oxide, silicon nitride, silicon oxynitride, epoxy resin, and polyimide. The thickness of the insulating layer 20 is not particularly limited, but may be 100 nm or more and 3000 nm or less.

[0019] An opening 21 is provided in the insulating layer 20. The opening 21 has any shape (e.g., circular, polygonal, etc.) when viewed from a direction perpendicular to the main surface 10a. The opening 21 in the insulating layer 20 has an inner circumferential surface 21a that extends in the up-down direction between the main surface 10a of the base material 10 and the main surface 20a of the insulating layer 20. In this embodiment, the inner circumferential surface 21a is inclined with respect to the main surface 10a. The configuration of the inner circumferential surface 21a will be described in detail later.

[0020] The electrode pad 30 is made of a metal material. The electrode pad 30 is an electrode provided near the opening 21 in the insulating layer 20 and extending in the normal direction to the main surface of the substrate 10. The electrode pad 30 includes a conductive layer 31 and a barrier layer 32. The conductive layer 31 is a portion located on the upper side of the insulating layer 20. The electrode pad 30 has any shape (e.g., circular, polygonal, etc.) when viewed from a direction perpendicular to the main surface 10a.

[0021] The conductive layer 31 is formed in the opening 21 of the insulating layer 20 so as to cover the opening 21. The conductive layer contains an element other than Au. The conductive layer 31 can be formed, for example, by sputtering or vacuum deposition of Cu. More specifically, the conductive layer 31 integrally covers the edge of the opening 21 on the main surface 20a of the insulating layer 20, the main surface 10a of the base material 10 exposed from the opening 21, and the inner circumferential surface 21a of the opening 21.

[0022] The barrier layer 32 is a layer that covers the conductive layer 31. The barrier layer 32 covers the entire outer surface 31a of the conductive layer 31. As described above, the conductive layer 31 covers the edge of the opening 21 in the insulating layer 20. Therefore, the barrier layer 32 also covers the edge of the opening 21 in the insulating layer 20. Therefore, the barrier layer 32 extends onto the insulating layer 20. The barrier layer 32 may contain any one or two of Ni, Ta, Ti, W, Mo, Cr, Zn, In, Nb, Sn, and C. The thickness of the barrier layer 32 may be 100 nm or more, or may be 300 nm or more. The thickness of the barrier layer 32 may be 3000 nm or less, or may be 1000 nm or less. The barrier layer 32 is not particularly limited, and may be formed by plating or the like.

[0023] Next, the cross-sectional shape of the electronic component 1 will be described. The inner peripheral surface 21a of the opening 21 forms a step portion 60 between the main surface 10a of the substrate 10 and the main surface 20a of the insulating layer 20. The inner peripheral surface 21a of the opening 21, i.e., the step portion 60, is inclined with respect to the main surface 10a of the substrate 10. The step portion 60 is inclined toward the outer periphery as it moves from the main surface 10a of the substrate 10 toward the main surface 20a of the insulating layer 20. The cross-sectional shape of the step portion 60 is inclined to form a straight line. However, the shape of the step portion 60 does not have to be a straight line and may be a curved line. The inclination angle θ1 of the step portion 60 may be 40° or more, or 50° or more. Furthermore, the inclination angle θ1 may be 70° or less, or 60° or less. The inclination angle θ1 is the angle with respect to the main surface 10a.

[0024] The conductive layer 31 covers the exposed main surface 10a, the inclined step portion 60, and the main surface 20a of the insulating layer 20 in the opening 21. Therefore, the surface 31b of the conductive layer 31 corresponding to the step portion 60 in the opening 21 is inclined. The inclination angle θ2 of the outer surface 31a may be 110° or more, or 120° or more. The inclination angle θ2 may be 140° or less, or 130° or less. The inclination angle θ2 is an angle with respect to the main surface 10a.

[0025] The electrode pad 30 has a shape that rises upward from the substrate 10. The electrode pad 30 has edge portions 40A and 40B, rising portions 41A and 41B, and a main body portion 42. The rising portions 41 are portions that rise upward from the insulating layer 20. The main body portion 42 is a portion that is formed thick at the center of the electrode pad 30. The thickness T of the conductive layer 31 in the main body portion 42 may be 100 nm or more and may be 5000 nm or less.

[0026] In this embodiment, the outer surface 31 a of the conductive layer 31 and the outer surface 32 a of the barrier layer 32 have the same shape and are substantially parallel to each other. The outer surface of the electrode pad 30 corresponds to the outer surface 32 a of the barrier layer 32, which is the outermost layer.

[0027] In a cross-sectional view, the main body 42 has a pair of edge portions 40A, 40B and a pair of raised portions 41A, 41B on the left and right sides. The edge portions 40A, 40B are provided on the main surface 20a of the insulating layer 20. The edge portions 40A, 40B are formed by the barrier layer 32 extending further outward from the outer peripheral end of the conductive layer 31. This allows the outer peripheral end of the conductive layer 31 to be completely covered by the barrier layer 32. Note that the barrier layer 32 must be long enough to avoid contact with adjacent electrode pads 30. If the width of the barrier layer 32 is "d1" and the width of the conductive layer 31 is "d2," the relationship "d2 / d1 ≦ 0.98" may hold. Furthermore, if "d2 / d1 ≦ 0.96," the intrusion of the etching solution is more effectively prevented, and if "d2 / d1 ≦ 0.90," the intrusion of the etching solution is even more reliably prevented.

[0028] The rising portions 41A, 41B are inclined with respect to the main surface 20a of the insulating layer 20. Therefore, the side surfaces 41Aa, 41Ba of the barrier layer 32 corresponding to the rising portions 41A, 41B are inclined. These side surfaces 41Aa, 41Ba become the side surfaces of the electrode pad 30. The cross-sectional shapes of the side surfaces 41Aa, 41Ba are inclined to form a straight line. However, the shape of the side surfaces 41Aa, 41Ba does not have to be a straight line and may be a curved line. The inclination angle θ3 of the side surfaces 41Aa, 41Ba may be 45° or more and 80° or less.

[0029] The outer surfaces 31a, 32a of the main body 42 extend in the direction of the main surface 10a between the upper ends of the rising portions 41A and 41B. A recess 50 is formed in the center of the outer surfaces 31a, 32a of the main body 42. The recess 50 has a bottom surface 52 that is positioned lower than the top surface 51 of the main body 42, and a pair of side surfaces 53A, 53B that extend from the bottom surface 52 to the top surface 51.

[0030] As described above, a method for providing a slope to the step portion 60 will be described. For example, as in Japanese Patent No. 4361415, a resist with an opening formed therein is heat-treated (post-baked) to make the resist sloped. In addition, the step portion 60 formed in the insulating layer 20 can be sloped by performing an anisotropic etching process such as reactive ion etching (RIE). Furthermore, the process gas used in reactive ion etching (for example, CHF when etching thermally oxidized silicon) is ３ and O ２ By changing the mixture ratio of the gases (a mixed gas of the above gases is used), the selectivity to the resist can be controlled, and the inclination angle of the step portion 60 can be finely adjusted.

[0031] The functions and effects of the electronic component 1 according to this embodiment will be described.

[0032] The electrode pad 30 is formed in a step portion 60 in the insulating layer 20 on the substrate 10. For example, as a comparative example, consider a structure in which the step portion 60 is perpendicular to the main surface 10a. In this case, as shown in FIGS. 2( a) and 2(b), the growth rate of the conductive layer 31 is slower in the step portion 60 than on the main surface 10a below the step portion 60, making seams more likely to occur. As shown in FIG. 2(a), when the film TL for forming the conductive layer 31 is stacked, if the growth of the film TL on the step portion 60 is slow, an overhang OH (eaves) is formed on the top of the step portion 60 where the growth is fast. If the film TL is stacked in this state, the growth of the film TL in the step portion 60 will be further slowed due to the shadow of the overhang OH. As a result, a seam SM is generated, as shown in FIG. 2(b).

[0033] In contrast, in this embodiment, the surface 31b of the conductive layer 31 corresponding to the step portion 60 is inclined. This promotes continuous growth of the conductive layer 31 in the step portion 60, thereby suppressing the occurrence of seams or reducing the seam size. For example, as shown in FIG. 2(c), the inclination of the step portion 60 can improve the growth rate of the film TL. As a result, as shown in FIG. 2(d), even if there is an overhang OH, the influence on the growth of the film TL in the step portion 60 can be reduced. By suppressing seams in the conductive layer 31, the formation of seams in the barrier layer 32 can be suppressed. Furthermore, since the barrier layer 32 covers the conductive layer 31, even if a seam occurs in the conductive layer 31, penetration of the etching solution into the seam can be suppressed. Note that if a thin film 33 is further formed as shown in FIG. 3(b), penetration of the etching solution can be suppressed. As a result, the reliability of the electronic component 1 can be improved.

[0034] The side surfaces 41Aa, 41Ba of the barrier layer 32 may be inclined. For example, if the side surfaces 41Aa, 41Ba of the barrier layer 32 are not inclined, voids may be formed between the barrier layer 32 and the conductive layer 31 at the base of the electrode pad 30 during the formation of the barrier layer 32. The barrier layer 32 may then peel off from the voids, potentially allowing an etching solution or the like to enter the conductive layer 31. In contrast, if the side surfaces 41Aa, 41Ba of the barrier layer 32 are inclined, the formation of voids is suppressed, the barrier layer 32 is less likely to peel off, and the intrusion of an etching solution or the like can be more reliably prevented.

[0035] The inclination angle θ2 of the surface 31b corresponding to the step portion 60 may be 110° or more and 140° or less. When the inclination angle θ2 is 110° or more, the occurrence of seams can be suppressed. Furthermore, when the inclination angle θ2 is 140° or less, the width of the electrode pad 30 can be prevented from becoming too wide.

[0036] The conductive layer 31 may contain elements other than Au. Although Au is stable against the etching solution, the presence of other elements in the conductive layer 31 may cause the formed seam to corrode and expand due to the etching solution, increasing the risk of reduced reliability of the element. Therefore, the effect of the present disclosure in suppressing the seam becomes more pronounced.

[0037] The substrate 10 may contain GaN. ２ O ２ A chemical solution containing this H is often used. ２ O ２ oxidizes GaN and ２ O ３ When GaN is used as the substrate, the conductive layer may be corroded and H ２ O ２ When the GaN layer penetrates into the substrate, Ga is formed between the GaN and the conductive layer. ２ O ３ Therefore, the present disclosure can be more effective when the substrate contains GaN.

[0038] The barrier layer 32 may contain at least one of Ni, Ta, Ti, W, Mo, Cr, Zn, In, Nb, Sn, and C. In this case, the corrosion resistance of the barrier layer 32 against the etching solution can be improved. Therefore, corrosion of the conductive layer 31 due to damage caused by corrosion of the barrier layer 32 can be suppressed.

[0039] The present disclosure is not limited to the above-described embodiments.

[0040] For example, as shown in Fig. 3A, the width of the electrode pad 30 may be smaller overall compared to the structure in Fig. 1. In this case, the width of the recess 50 may be smaller. Also, the conductive layer 31 may not extend onto the main surface 20a of the insulating layer 20. Such a structure can be achieved by narrowing the opening in the resist during manufacturing.

[0041] 3(b), the electronic component 1 may further include a thin film 33 formed on the barrier layer 32. The thin film 33 covers the entire barrier layer 32. The material of the thin film 33 is not particularly limited, but may be, for example, Au, Sn, or Pd. The thickness of the thin film 33 is not particularly limited, but may be 10 nm or more and 300 nm or less. In this case, even if a defect such as a hole exists in the barrier layer 32, the thin film 33 can cover the defect. Therefore, corrosion of the conductive layer 31 by the etching solution can be more reliably suppressed. The thin film 33 may also be applied to electronic components 1 shown in other figures.

[0042] For example, as shown in Fig. 4, the width of the recess 50 may be larger than that of the structure shown in Fig. 1. Also, the side surfaces 41Aa, 41Ba of the electrode pad 30 may be inclined at an angle close to vertical. Such a structure can be obtained by reducing the pressure of the gas atmosphere during film formation by sputtering or the like to increase the linearity of the particles.

[0043] 5, the outer peripheral end of the conductive layer 31 may be disposed in the step portion 60. In this case, the barrier layer 32 is configured to sink into the gap between the conductive layer 31 and the step portion 60. Note that since the amount by which the electrode pad 30 extends over the step portion 60 is small, the depth of the recess 50 is also shallow. Such a structure can be formed by narrowing the opening in the resist during manufacturing.

[0044] 6, a structure may be employed in which the recess 50 is filled with the barrier layer 32. Such a structure can be formed by using resists with different diameters multiple times and forming the barrier layer 32 in multiple steps.

[0045] 7, the upper surface of the electrode pad 30 may be flattened so as to prevent the formation of the recess 50. Such a structure can be achieved by using resists with different diameters multiple times and forming the conductive layer 31 in multiple steps.

[0046] For example, as shown in Fig. 8, the recess 50 may be configured to be shallower than that shown in Fig. 1. Such a structure can be achieved by reducing the inclination of the step portion 60.

[0047] For example, as shown in Fig. 9A, the end of the barrier layer 32 may be configured to become gradually thinner as it goes upward. This configuration reduces the steps formed in the barrier layer 32 itself. Therefore, stress can be suppressed from being applied to the steps in the barrier layer 32, making the barrier layer 32 less likely to peel off. This more reliably prevents the intrusion of the etching solution.

[0048] 9B, the end of the conductive layer 31 may also have a gradually gentler slope going upward. This shape makes the angle change at the boundary between the terminal of the conductive layer 31 and the insulating layer 20 gentler, making it difficult for the barrier layer 32 present on the boundary to peel off. This makes it possible to more reliably prevent the intrusion of the etching solution.

[0049] [Mode 1] An electronic component comprising: a substrate having a main surface; an insulating layer disposed on the main surface of the substrate and having a stepped portion; a conductive layer formed on the insulating layer in the stepped portion; and a barrier layer covering the conductive layer, wherein a surface of the conductive layer corresponding to the stepped portion is inclined. [Mode 2] The electronic component according to Mode 1, wherein a side surface of the barrier layer is inclined. [Mode 3] The electronic component according to Mode 1 or 2, wherein the inclination angle of the surface corresponding to the stepped portion is 110° or more and 140° or less. [Mode 4] The electronic component according to any one of Modes 1 to 3, wherein the conductive layer contains an element other than Au. [Mode 5] The electronic component according to any one of Modes 1 to 4, wherein the substrate contains GaN. [Mode 6] The electronic component according to any one of Modes 1 to 5, wherein the barrier layer contains at least one of Ni, Ta, Ti, W, Mo, Cr, Zn, In, Nb, Sn, and C. [Mode 7] The electronic component according to any one of Modes 1 to 6, further comprising a thin film formed on the barrier layer.

[0050] 1...electronic component, 10...substrate, 20...insulating layer, 30...electrode pad, 31...conductive layer, 32...barrier layer, 41Aa, 41Ba...side surface, 60...step portion

Claims

1. An electronic component comprising: a substrate having a main surface; an insulating layer disposed on the main surface of the substrate, the insulating layer having a stepped portion; a conductive layer formed on the insulating layer in the stepped portion; and a barrier layer covering the conductive layer, wherein a surface of the conductive layer corresponding to the stepped portion has an inclination.

2. The electronic component according to claim 1, wherein the side surface of the barrier layer has a slope.

3. The electronic component according to claim 1, wherein the inclination angle of the surface corresponding to the step portion is not less than 110° and not more than 140°.

4. The electronic component according to claim 1, wherein the conductive layer contains an element other than Au.

5. The electronic component of claim 1, wherein the substrate comprises GaN.

6. The electronic component according to claim 1, wherein the barrier layer contains at least one of Ni, Ta, Ti, W, Mo, Cr, Zn, In, Nb, Sn, and C.

7. The electronic component according to claim 1, further comprising a thin film formed on said barrier layer.

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