Metal connection structure, semiconductor device with metal connection structure and wafer structure

Abstract

The utility model discloses a metal connection structure, which comprises a bottom metal layer, an insulating layer, a conductive layer, a metal wiring layer and a passivation layer which are arranged in sequence, the insulating layer is provided with an opening, the conductive layer is in contact with the bottom metal layer through the opening, and the metal wiring layer is arranged on the conductive layer; wherein the conductive layer covers the bottom and the side wall of the opening and extends outwards to the surface of the insulating layer on the periphery of the opening, the conductive layer sequentially comprises an adhesion layer and a seed layer, the length of the adhesion layer extending towards the surface of the insulating layer is larger than that of the seed layer extending towards the surface of the insulating layer, and the edge of the metal wiring layer is flush with the edge of the seed layer. And after the passivation layer is deposited, cracks are not easy to generate at the joint, so that the passivation effect of the passivation layer is ensured, and the product reliability is improved. The utility model also discloses a semiconductor device with the metal connection structure and a wafer structure.

Description

Technical Field

[0001] The utility model belongs to the technical field of semiconductor devices, and in particular relates to a metal connection structure, a semiconductor device having the metal connection structure, and a wafer structure. Background Art

[0002] In the semiconductor production process, the preparation methods of metal layers are divided into two methods: evaporation and electroplating. Among them, the cost of the electroplating process is lower than that of evaporation, and it has more advantages, so the electroplating preparation method has been introduced into the preparation of metal connection structures of compound semiconductor circuits. In the metal electroplating process, a sputtering process and other processes are first used to form a conductive layer on the entire surface, and a metal wiring layer is formed on the conductive layer in a specific area. After the electroplating is completed, the excess conductive layer on the surface needs to be etched away to disconnect the interconnection between the electroplated metals. The existing etching process will produce an etching condition in which the conductive layer penetrates deep into the metal wiring layer, which will etch a concave morphology at the bottom of the electroplated metal. This morphology will form tiny cracks in the subsequent deposition of the passivation layer. The cracks are one of the reasons for the failure of the product in the subsequent reliability test, affecting the production yield and performance of the product. Utility Model Content

[0003] The utility model aims at the deficiencies in the prior art and provides a metal connection structure, a semiconductor device having the metal connection structure and a wafer structure.

[0004] In order to achieve the above objectives, the technical solution of the utility model is:

[0005] A metal connection structure comprises a bottom metal layer, an insulating layer, a conductive layer, a metal wiring layer and a passivation layer arranged in sequence; the insulating layer has an opening on the bottom metal layer, the conductive layer contacts the bottom metal layer through the opening, and the metal wiring layer is arranged on the conductive layer; wherein the conductive layer covers the bottom and side walls of the opening and extends outward to the surface of the insulating layer at the periphery of the opening, the conductive layer comprises an adhesion layer and a seed layer in sequence, the attachment layer extends to the surface of the insulating layer by a length greater than the seed layer extends to the surface of the insulating layer, and the edge of the metal wiring layer is flush with the edge of the seed layer.

[0006] Optionally, the edge of the adhesion layer extends outward by 0.1-0.3 μm relative to the edge of the seed layer.

[0007] Optionally, the material of the adhesion layer is titanium-tungsten alloy, and the thickness is 40-80 nm.

[0008] Optionally, the material of the seed layer and the metal wiring layer is gold, wherein the thickness of the seed layer is 100-150 nm, and the thickness of the metal wiring layer is 2-6 μm.

[0009] Optionally, the thickness of the insulating layer is 100-500 nm.

[0010] Optionally, the side wall of the opening is inclined from the outside to the inside of the opening and the thickness gradually decreases, and the inclination angle relative to the surface of the bottom metal layer is 20° to 60°.

[0011] Optionally, the passivation layer is located in the outer layer, covering the metal wiring layer, the insulating layer and the exposed surface of the conductive layer, and the material of the passivation layer is silicon nitride or silicon oxide, and the deposition thickness is 80 to 150 nm.

[0012] A semiconductor device with a metal connection structure comprises a semiconductor substrate and the above-mentioned metal connection structure, wherein the bottom metal layer is arranged on the semiconductor substrate, the insulating layer covers the bottom metal layer and the semiconductor substrate and has an opening on the bottom metal layer.

[0013] Optionally, the semiconductor device includes a HBT device.

[0014] A wafer structure with a metal connection structure comprises a plurality of device units, each device unit having the above-mentioned metal connection structure on a semiconductor substrate wafer.

[0015] The beneficial effects of the utility model are:

[0016] The adhesion layer is extended outward by a certain length relative to the seed layer and the metal connection layer, and a transition morphology of the electroplated metal-insulating layer surface is formed through the extended adhesion layer. After the passivation layer is deposited, cracks are not easy to form at the connection, which ensures the passivation effect of the passivation layer, prevents water vapor from invading the metal through the cracks in the passivation layer, and improves product reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of a metal connection structure of an embodiment;

[0018] Figure 2 A schematic diagram of a shielding layer structure for etching a conductive layer of a metal connection structure according to an embodiment;

[0019] Figure 3 A schematic diagram of a metal connection structure of a comparative example;

[0020] Figure 4 is a partial schematic diagram of a semiconductor device with a metal connection structure according to an embodiment;

[0021] Figure 5 FIG. 4 is a partial schematic diagram of a wafer structure with a metal connection structure according to an embodiment. DETAILED DESCRIPTION

[0022] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. The drawings of the present invention are only for illustration to make it easier to understand the present invention, and the specific proportions can be adjusted according to design requirements. The upper and lower relationships of the relative elements and the definitions of the front and back sides in the figures described in the text should be understood by those skilled in the art to refer to the relative positions of the components, so they can all be flipped to present the same components, which should all fall within the scope disclosed in this specification.

[0023] refer to Figure 1 The metal connection structure of the embodiment includes a bottom metal layer 1, an insulating layer 2, a conductive layer 3, a metal wiring layer 4 and a passivation layer 5 arranged in sequence. The insulating layer 2 has an opening 2a on the bottom metal layer 1, and the conductive layer 3 is in contact with the bottom metal layer 1 through the opening 2a to achieve electrical connection. The metal wiring layer 4 is arranged on the conductive layer 3, and the passivation layer 5 covers the surface of the above structure. The conductive layer 3 covers the bottom and side walls of the opening 2a and extends outward to the surface of the insulating layer 2 at the periphery of the opening. The conductive layer 3 includes an adhesion layer 31 and a seed layer 32 in sequence. The length of the adhesion layer 31 extending to the surface of the insulating layer 2 is greater than the length of the seed layer 32 extending to the surface of the insulating layer 2, that is, the edge of the adhesion layer 31 extends outward by a certain length relative to the edge of the seed layer 32, and the edge of the metal wiring layer 4 is flush with the edge of the seed layer 32. Therefore, when the passivation layer 5 covers the surface, the transition area between the metal wiring layer 4 and the insulating layer 2 is transitioned through the adhesion layer 31, avoiding the situation where cracks are prone to occur there.

[0024] Specifically, the material of the insulating layer 2 is, for example, polyimide, and its thickness on the bottom metal layer 1 is 100 to 500 nm, for example, 200 nm. The side wall of the opening 2a of the insulating layer 2 is inclined from the outside of the opening to the inside and the thickness gradually decreases, and the inclination angle relative to the surface of the bottom metal layer 1 is 20° to 60°, for example, 45°. The inclination angle mentioned here refers to the angle between the straight line connecting the inner and outer end points of the side wall and the relative bottom metal layer 1. When actually set, the side wall can be set as an arc surface to provide a smooth transition. The adhesion layer 31 is used to improve the adhesion between the metal wiring layer 4 and the insulating layer 2. The material is titanium-tungsten alloy and the thickness is 40 to 80 nm, for example, 60 nm. The edge of the adhesion layer 31 extends outward by 0.1 to 0.3 μm, for example, 0.2 μm, relative to the edge of the seed layer 32. The material of the seed layer 32 and the metal wiring layer 4 is, for example, gold, wherein the thickness of the seed layer 32 is 100 to 150 nm, for example, 120 nm; the thickness of the metal wiring layer 4 is 2 to 6 μm, for example, 4 μm. The conductive layer 3 is formed by sequentially sputtering the adhesion layer 31 and the seed layer 32, and the metal wiring layer 4 is formed by electroplating. When electroplating is performed on an electroplating machine, the metal grows on the seed layer 32. The seed layer 32 can improve the conductivity of the plated layer and improve the adhesion of the electroplated metal.

[0025] The material of the passivation layer 5 is silicon nitride or silicon oxide, and the deposition thickness is 80 to 150 nm. For example, 100 nm of Si is deposited. 3 N 4 as a passivation layer.

[0026] When the above metal connection structure is manufactured, after manufacturing the bottom metal layer 1, the insulating layer 2 and the opening 2a thereof, the conductive layer 3 is sputtered on the entire surface, and metal is electroplated in a preset area by a photolithography process to form a metal wiring layer 4, and then a photoresist is used as a shielding layer R, which covers the surface and side walls of the metal wiring layer 4, and a certain thickness is retained on the outside of the side wall to protect the electroplated metal and its surrounding areas, such as Figure 2 As shown, the seed layer 32 and the attachment layer 31 are then etched in sequence. Even if side etching occurs, the etching endpoints of the seed layer 32 and the attachment layer 31 can still be controlled to be located outside the metal wiring layer 4 below the shielding layer R. After removing the shielding layer R, the seed layer 32 is etched again until the edge is flush with the edge of the metal wiring layer 4, and the morphology of the attachment layer 31 extending outward relative to the seed layer 32 and the metal wiring layer 4 can be obtained. Then, a passivation layer 5 is formed on the entire surface by, for example, MOCVD (metal organic chemical vapor deposition).

[0027] The edge of the adhesion layer 31 extends outward relative to the edge of the seed layer 32 and the metal wiring layer 4. On the one hand, the passivation layer 5 is formed on the surface of the adhesion layer 31 extending outward at the turning point between the electroplated metal bottom and the insulating layer. The extended adhesion layer 31 provides a transition. Figure 3 The inwardly concave morphology of the adhesion layer 33 in the comparative example shown avoids the problem of cracks in the passivation layer at that location, so that water vapor cannot penetrate the metal through the cracks, thereby improving the reliability of the product. At the same time, the outwardly extending portion of the adhesion layer 31 also ensures the adhesion performance of the electroplated metal edge, avoids local peeling of the edge, and disperses the deposition stress of the passivation layer, further improving the reliability. The above effect can be achieved when the outward extension length is 0.1 to 0.3 μm. If it exceeds this range, it will occupy a large area, which is not conducive to the miniaturization of the device.

[0028] refer to Figure 4, the semiconductor device with a metal connection structure of the embodiment includes a semiconductor substrate 6 and the above-mentioned metal connection structure. The semiconductor device is, for example, an HBT device, wherein the bottom metal layer 1 is, for example, a metal electrode disposed on the surface of the semiconductor substrate 6, specifically, a titanium / platinum / gold stack, with thicknesses of 1μm / 2μm / 4μm, respectively. The insulating layer 2 covers the bottom metal layer 1 and the surface of the semiconductor substrate 6 to provide insulation and high filling effects. The conductive layer 3 and the metal wiring layer 4 are used to make an external structure of the metal electrode, and the insulating layer 2 forms an opening 2a to give way to the external structure. It should be noted that the figure only shows a partial structure of the device. In fact, there may be multiple metal electrodes and their external structures that are synchronously made on different functional layers of the semiconductor substrate 6. The conductive layer 3 is sputtered on the entire surface during sputtering, and the conductive layer is etched to disconnect the connection after the electroplating metal is made.

[0029] refer to Figure 5 , the wafer structure with a metal connection structure of the embodiment is formed on a semiconductor substrate wafer 7 to form a plurality of device units 71, each device unit 71 having the above-mentioned metal connection structure. The conductive layer 3 is sputtered on the entire surface, and the conductive layer on the surface is etched off after the electroplated metal is made to disconnect the interconnection between the electroplated metals. After the entire surface is made, a semiconductor device is obtained by a cutting process. It should be noted that the figure only shows a partial structure of the device.

[0030] The above embodiments are only used to further illustrate a metal connection structure of the utility model, a semiconductor device and a wafer structure having the metal connection structure, but the utility model is not limited to the embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the utility model shall fall within the protection scope of the technical solution of the utility model.

Claims

1. A metal connection structure, characterized in that: It includes a bottom metal layer, an insulating layer, a conductive layer, a metal wiring layer and a passivation layer; the insulating layer has an opening on the bottom metal layer, the conductive layer contacts the bottom metal layer through the opening, and the metal wiring layer is arranged on the conductive layer; The conductive layer covers the bottom and side walls of the opening and extends outward to the surface of the insulating layer at the periphery of the opening. The conductive layer includes an adhesion layer and a seed layer in sequence. The length of the adhesion layer extending to the surface of the insulating layer is greater than the length of the seed layer extending to the surface of the insulating layer. The edge of the metal wiring layer is flush with the edge of the seed layer.

2. The metal connection structure according to claim 1, characterized in that: The edge of the adhesion layer extends outward by 0.1 to 0.3 μm relative to the edge of the seed layer.

3. The metal connection structure according to claim 1, characterized in that: The material of the adhesion layer is titanium-tungsten alloy, and the thickness is 40-80nm.

4. The metal connection structure according to claim 1, characterized in that: The material of the seed layer and the metal wiring layer is gold, wherein the thickness of the seed layer is 100-150 nm, and the thickness of the metal wiring layer is 2-6 μm.

5. The metal connection structure according to claim 1, characterized in that: The thickness of the insulating layer is 100-500 nm.

6. The metal connection structure according to claim 1, characterized in that: The side wall of the opening is inclined from the outside to the inside of the opening and the thickness gradually decreases. The inclination angle relative to the surface of the bottom metal layer is 20° to 60°.

7. The metal connection structure according to claim 1, characterized in that: The passivation layer covers the metal wiring layer, the insulating layer and the exposed surface of the conductive layer. The material of the passivation layer is silicon nitride or silicon oxide, and the thickness is 80-150nm.

8. A semiconductor device having a metal connection structure, characterized in that: It comprises a semiconductor substrate and the metal connection structure according to any one of claims 1 to 7, wherein the bottom metal layer is arranged on the semiconductor substrate, and the insulating layer covers the bottom metal layer and the semiconductor substrate and has an opening on the bottom metal layer.

9. The semiconductor device according to claim 8, characterized in that: The semiconductor device includes a HBT device.

10. A wafer structure having a metal connection structure, characterized in that: The wafer structure comprises a plurality of device units, each of which is provided with a metal connection structure as claimed in any one of claims 1 to 7 on a semiconductor substrate wafer.

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