Electronic component

Abstract

To provide an electronic component capable of improving the reliability thereof.SOLUTION: A surface 31b, of a conductive layer 31, corresponding to a step part 60 has a slant. Thus, by promoting a continuous growth of a film of the conductive layer 31 at the step part 60, occurrence of seams can be suppressed or a seam size can be reduced. For example, as shown in Figure 2(c), by providing a slant to the step part 60, the growth rate of a film TL can be improved. As a result, as shown in Figure 2(d), even if there is an overhang OH, effects on the growth of the film TL at the step part 60 can be reduced. In addition, the conductive layer 31 covers a barrier layer 32, so that, even if seams occur, permeation of an etching solution into the seams can be suppressed. Thus, the improvement of an electronic component 1 can be improved.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to electronic components. [Background technology]

[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 an etching solution used in a later process may penetrate through the seam, resulting in a decrease in reliability of elements (e.g., wiring layers and gate electrodes) that constitute the step. In response to this, Patent Document 1 discloses a technology in which an insulating layer that covers a wiring layer has a multi-layer structure to make the seam discontinuous. Patent Document 2 discloses an electronic component in which a barrier metal layer is formed on an electrode layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 183390 [Patent Document 2] JP 2013-80978 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, Patent Document 1 does not prevent the occurrence of seams themselves, and if a defect occurs such as film formation with voids (air gaps) occurring in the interlayer areas where the seams are discontinuous, the seams may join and allow chemicals, moisture, undesired gases, etc. to penetrate, resulting in reduced 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 invention is to provide an electronic component that can improve reliability. [Means for solving the problem]

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

[0007] The electronic component according to the present invention has a conductive layer formed in a step portion on an insulating layer. The step portion has a slower film growth rate of the conductive layer than the bottom surface of the step portion, so that seams are more likely to occur. In contrast, in the present invention, the surface of the conductive layer corresponding to the step portion has an inclination. This promotes continuous growth of the conductive layer film in the step portion, and can suppress the occurrence of seams or reduce the seam size. By suppressing seams in the conductive layer, it is possible to suppress the occurrence of seams in the barrier layer. Furthermore, since the barrier layer covers the conductive layer, even if a seam occurs in the conductive layer, it is possible to suppress the intrusion of an etching solution into the seam. As a result, the reliability of the electronic component can be improved.

[0008] The side surface of the barrier layer may have a slope. For example, if the side surface of the barrier layer does not have a slope, a void may be formed between the barrier layer and the conductive layer at the base of the electrode pad when the barrier layer is formed. The barrier layer may then peel off from the void, which may lead to the intrusion of an etching solution or the like into the conductive layer. In contrast, if the side surface of the barrier layer has a slope, the formation of a void is suppressed, the barrier layer is less likely to peel off, and the intrusion of an etching solution or the like 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 suppress the occurrence of seams. Also, by setting the inclination angle to 140° or less, the width of the electrode pad can be prevented 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 increases the risk of the formed seam being corroded and expanded by the etching solution, which may result in a decrease in the reliability of the element. Therefore, the effect of the present invention in suppressing the seam becomes more pronounced.

[0011] The substrate may contain GaN. A chemical solution containing H2O2 is often used as an etching solution. This H2O2 may oxidize GaN and form Ga2O3. Therefore, when GaN is used as the substrate, if the conductive layer is corroded and H2O2 penetrates into the substrate, Ga2O3 may be formed between the GaN and the conductive layer, and the substrate may no longer function as a semiconductor. Therefore, the effect of the present invention can be more pronounced when the substrate contains GaN.

[0012] The barrier layer may be made of a material containing 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. Therefore, the conductive layer can be prevented from being corroded due to damage caused by the corrosion of the barrier layer.

[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. Effect of the Invention

[0014] According to the present invention, it is possible to provide an electrode pad and an electronic component that can improve reliability. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic cross-sectional view showing an electrode pad and an electronic component according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view for explaining the action and effect. [Diagram 3]13 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example. [Figure 4] 13 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example. [Diagram 5] 13 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example. [Figure 6] 13 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example. [Figure 7] 13 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example. [Figure 8] 13 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example. [Figure 9] 13 is a schematic cross-sectional view showing an electrode pad and an electronic component according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The configurations of an electrode pad and an electronic component according to the 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, as an 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 include GaN. Alternatively, the substrate 10 may include 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 made of an oxide or nitride containing at least one of the elements 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 extending 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 of the insulating layer 20 and extending in the normal direction of the main surface of the base material 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 of the insulating layer 20. Therefore, the barrier layer 32 also covers the edge of the opening 21 of 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 becomes 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 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 draw 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, and may be 50° or more. The inclination angle θ1 may be 70° or less, and may be 60° or less. The inclination angle θ1 is an 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 of the opening 21 has an inclination. 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, 40B, rising portions 41A, 41B, and a main body portion 42. The rising portion 41 is a portion that rises upward from the insulating layer 20. The main body portion 42 is a portion that is formed thick at the center position 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 31a of the conductive layer 31 and the outer surface 32a of the barrier layer 32 have the same shape and are in a substantially parallel relationship. The outer surface of the electrode pad 30 corresponds to the outer surface 32a 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 rising 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 from the outer peripheral end of the conductive layer 31 toward the outer peripheral side. As a result, the vicinity of the outer peripheral end of the conductive layer 31 is completely covered with the barrier layer 32. The barrier layer 32 needs to be long enough not to contact other adjacent electrode pads 30. If the width dimension of the barrier layer 32 is "d1" and the width dimension of the conductive layer 31 is "d2", the relationship "d2 / d1 ≦ 0.98" may be established. Furthermore, if "d2 / d1 ≦ 0.96", the intrusion of the etching solution can be more effectively prevented, and if "d2 / d1 ≦ 0.90", the intrusion of the etching solution can be 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 have an inclination. These side surfaces 41Aa, 41Ba become the side surfaces of the electrode pad 30. The cross-sectional shape of the side surfaces 41Aa, 41Ba is inclined so as to draw 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 in which the main surface 10a extends 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 located 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 of providing a slope to the step portion 60 will be described. For example, as in Patent No. 4361415, a resist having an opening formed therein is heat-treated (post-baked) to slope the resist, and anisotropic etching such as reactive ion etching (RIE) is then performed on the resist to slope the step portion 60 formed in the insulating layer 20. Furthermore, by changing the mixture ratio of the process gas used in the reactive ion etching (for example, a mixture of CHF3 and O2 gas is used when etching thermally oxidized silicon), the selectivity to the resist can be controlled, and the slope angle of the step portion 60 can be finely adjusted.

[0031] The operation and effect 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, a structure in which the step portion 60 is perpendicular to the main surface 10a is given. In this case, as shown in FIG. 2(a)(b), the growth rate of the conductive layer 31 is slower in the step portion 60 than in the main surface 10a on the bottom side of the step portion 60, so that a seam is more likely to occur. As shown in FIG. 2(a), when the film TL for constituting the conductive layer 31 is laminated, if the growth of the film TL on the step portion 60 is slow, an overhang OH (eaves) is formed on the upper part of the step portion 60 where the film TL grows quickly. If the film TL is laminated in this state, the growth of the film TL in the step portion 60 will be further slowed down due to being in 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 has an inclination. This promotes continuous growth of the film of the conductive layer 31 in the step portion 60, and can suppress the occurrence of seams or reduce the seam size. For example, as shown in FIG. 2(c), the step portion 60 has an inclination, so that the growth rate of the film TL can be improved. 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 the seam of the conductive layer 31, it is possible to suppress the occurrence of a seam in the barrier layer 32. In addition, since the barrier layer 32 covers the conductive layer 31, even if a seam occurs in the conductive layer 31, it is possible to suppress the intrusion of the etching solution into the seam. Note that when a thin film 33 as shown in FIG. 3(b) is further formed, the intrusion 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 have an incline. For example, if the side surfaces 41Aa, 41Ba of the barrier layer 32 are not inclined, there is a possibility that a void will be formed between the barrier layer 32 and the conductive layer 31 at the base of the electrode pad 30 when the barrier layer 32 is formed. The barrier layer 32 may then peel off from the void, which may cause an etching solution or the like to mix with the conductive layer 31. In contrast, by forming the side surfaces 41Aa, 41Ba of the barrier layer 32 with an incline, the formation of a void is suppressed, the barrier layer 32 becomes less likely to peel off, and the effect of preventing the mixing with an etching solution or the like can be more reliably obtained.

[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 effect of suppressing the occurrence of seams can be obtained. Moreover, 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 to the etching solution, the presence of other elements in the conductive layer 31 increases the risk of the formed seam being corroded and expanded by the etching solution, which may result in a decrease in the reliability of the element. Therefore, the effect of the present invention in suppressing the seam becomes more pronounced.

[0037] The substrate 10 may contain GaN. A chemical solution containing H2O2 is often used as an etching solution. This H2O2 can oxidize GaN and form Ga2O3, so when GaN is used as the substrate, if the conductive layer is corroded and H2O2 penetrates into the substrate, Ga2O3 is formed between the GaN and the conductive layer, and the substrate may no longer function as a semiconductor. Therefore, the present invention can be more effective when the substrate contains GaN.

[0038] The barrier layer 32 may be made of a material containing 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, the conductive layer 31 can be prevented from being corroded due to damage caused by the corrosion of the barrier layer 32.

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

[0040] For example, as shown in Fig. 3(a), the width of the electrode pad 30 may be smaller overall as 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 formed by narrowing the opening of the resist during manufacturing.

[0041] Also, as in the electronic component 1 shown in FIG. 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, Pd, or the like. 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 be applied to the electronic component 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 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 lowering the pressure of the gas atmosphere and increasing the linearity of the particles when forming a film by sputtering or the like.

[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 structured to be embedded in the gap between the conductive layer 31 and the step portion 60. Since the amount of the electrode pad 30 that rides on 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 of the resist during manufacturing.

[0044] 6, a structure may be adopted in which the recess 50 is filled with the barrier layer 32. Such a structure can be formed by using resists having 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 having 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 in Fig. 1. Such a structure can be achieved by making the inclination of the step portion 60 smaller.

[0047] For example, as shown in Fig. 9(a), a configuration may be adopted in which the end of the barrier layer 32 becomes gradually thinner toward the top. With such a shape, the step formed in the barrier layer 32 itself becomes smaller. Therefore, it is possible to suppress the application of stress to the step of the barrier layer 32, and the barrier layer 32 becomes more difficult to peel off. This makes it possible to more reliably prevent the intrusion of the etching solution.

[0048] 9(b), the end of the conductive layer 31 may also have a gradually gentler inclination toward the top. With this shape, the angle change at the boundary between the terminal of the conductive layer 31 and the insulating layer 20 becomes gentle, and the barrier layer 32 existing on the boundary becomes less likely to peel off. This makes it possible to more reliably prevent the intrusion of the etching solution.

[0049] [Form 1] A substrate having a main surface; an insulating layer disposed on the main surface of the base material and having a step portion; a conductive layer formed on the step portion on the insulating layer; a barrier layer covering the conductive layer; a surface of the conductive layer corresponding to the step portion has an inclination. [Form 2] 2. The electronic component of claim 1, wherein the side surface of the barrier layer has a slope. [Form 3] 3. The electronic component according to claim 1, wherein an inclination angle of the surface corresponding to the step portion is 110° or more and 140° or less. [Form 4] 4. The electronic device according to claim 1, wherein the conductive layer contains an element other than Au. [Form 5] 5. The electronic device according to claim 1, wherein the substrate comprises GaN. [Form 6] 6. The electronic device according to any one of aspects 1 to 5, wherein the barrier layer is made of a material containing at least one of Ni, Ta, Ti, W, Mo, Cr, Zn, In, Nb, Sn, and C. [Form 7] 7. The electronic device according to any one of embodiments 1 to 6, further comprising a thin film formed on the barrier layer. [Explanation of symbols]

[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. A substrate having a main surface; an insulating layer disposed on the main surface of the base material and having a step portion; a conductive layer formed on the step portion on the insulating layer; a barrier layer covering the conductive layer; a surface of the conductive layer corresponding to the step portion has an inclination.

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

3. The electronic component according to claim 1 , wherein an 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. 2. The electronic component according to claim 1, wherein the barrier layer is made of a material containing 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 the barrier layer.

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