Air bridge manufacturing method and air bridge

Abstract

The invention relates to an air bridge processing method and an air bridge, and the method comprises the following steps: completing a first electrode and a second electrode on a semiconductor material, coating a first photoresist layer, carrying out the exposure / development, carrying out the baking, and depositing a dielectric layer on the whole upper surface after the baking; coating a second photoresist layer at a position corresponding to the first photoresist layer on the dielectric layer, etching the dielectric layer outside the second photoresist layer after exposure / development, and then removing the second photoresist layer; a third photoresist layer is coated on the semiconductor material around the first electrode and the second electrode and on the dielectric layer at the position where the bridge hole is to be formed, the photoresist is negative photoresist, and exposure / development is carried out; and evaporating a third electrode on the whole upper surface, and removing the third photoresist layer, the dielectric layer below the third photoresist layer at the position to be provided with the bridge hole and the first photoresist layer to complete the whole air bridge manufacturing process. According to the invention, the pressure resistance in a vertical space can be improved, and the high-pressure washing resistance of the bridge on the horizontal plane is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to an air bridge manufacturing method and an air bridge. Background Art

[0002] Air bridge is an innovative three-dimensional interconnect structure. It is built by suspending the bridge on the surface of the chip. As a key structure in semiconductors, air bridge has been maturely applied in compound semiconductor processes (such as GaAs and GaN) to connect two contacts and cross other lines. Common manufacturing processes include Figure 1 and Figure 2 As shown: first, a removable material (such as photoresist) is deposited to fill the reserved space under the bridge body, and then a metal bridge structure is formed by electroplating or deposition. Finally, the sacrificial layer is selectively etched to remove the overhead channel. However, the air bridge made by the conventional manufacturing process has poor compressive performance in the vertical direction and is easily collapsed, resulting in abnormal appearance. The air bridge has poor anti-washing ability in the horizontal direction, especially when the bridge deck is narrow, it is easy to be broken or cracked. Summary of the Invention

[0003] The object of the present invention is to provide an air bridge manufacturing method and an air bridge, which can improve the pressure resistance in the vertical space and improve the bridge's resistance to high-pressure flushing on the horizontal surface.

[0004] To achieve the above object, the present invention provides the following technical solution: an air bridge process method, comprising the following steps:

[0005] Step S1: forming a first electrode and a second electrode on a semiconductor material, coating a first photoresist layer, exposing / developing the material, and baking the material. After baking, a dielectric layer is deposited on the entire upper surface of the material.

[0006] Step S2: coating a second photoresist layer on the dielectric layer at a position corresponding to the first photoresist layer, and after exposure / development, etching the dielectric layer outside the second photoresist layer, and then removing the second photoresist layer;

[0007] Step S3, coating a third photoresist layer on the semiconductor material around the positions of the first electrode, the second electrode and the position of the bridge hole to be made on the dielectric layer, wherein the photoresist is a negative photoresist, and performing exposure / development;

[0008] Step S4: vapor-deposit the third electrode on the entire upper surface, remove the third photoresist layer, the dielectric layer under the third photoresist layer at the location where the bridge hole is to be made, and the first photoresist layer, and complete the entire air bridge process.

[0009] Furthermore, the dielectric layer is deposited using plasma-assisted atomic layer deposition technology, and the deposition temperature is below 80°C.

[0010] Furthermore, the material of the dielectric layer is Al2O3, TiO2, Ta2O5, ZrO2, HfO2, SnO2, ZnO, La2O3, V2O5 or SiO2, and the thickness of the dielectric layer is 10nm to 100nm.

[0011] Furthermore, the materials of the first photoresist layer, the second photoresist layer and the third photoresist layer are all composed of resin and photosensitizer, the thickness of the second photoresist layer is greater than 3 μm, and the thickness of the third photoresist layer is 4-6 μm.

[0012] Furthermore, the material of the third electrode is Ti, Pt or Au, and the thickness of the third electrode is 2um to 4um.

[0013] Furthermore, after exposure / development in step S3, the third photoresist layer at the positions of the first electrode and the second electrode forms a regular trapezoidal cross-section.

[0014] Furthermore, the area of ​​the second photoresist layer in the dielectric layer is larger than the upper surface area of ​​the air bridge.

[0015] An air bridge comprises an air bridge body and a semiconductor material, wherein a plurality of stacked first electrodes and a second electrode are provided on the semiconductor material, the air bridge body comprises a bridge body and bridge piers, the bridge piers are provided on the second electrodes, the middle of the bridge body is raised in a half-mouth shape, and the bridge piers are connected to both ends, a dielectric layer is provided below the bridge body and is in contact with the bridge body, and bridge holes are provided on the left and right sides of the bridge body and the dielectric layer.

[0016] Furthermore, both ends of the dielectric layer are arranged on the second electrode.

[0017] The beneficial effects of the present invention are as follows: the air bridge manufactured by the process method of the present invention has a strong compressive resistance in the vertical space and is not easily collapsed, broken or cracked. By adding a dense dielectric layer under the air bridge, the compressive resistance in the vertical space is improved, and the appearance yield of the finished product is improved; two bridge holes are left on the bridge, which not only improves the efficiency of photoresist removal but also improves the bridge's resistance to high-pressure flushing on the horizontal plane. Compared with leaving no holes on the bridge, a narrower bridge deck can be achieved while ensuring the yield; it is beneficial to reduce space and improve integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A cross-sectional view (left) and a top view (right) of a metal bridge structure formed using an existing manufacturing method;

[0019] Figure 2 Cross-sectional view (left) and top view (right) of an air bridge formed by etching using an existing manufacturing method;

[0020] Figure 3 The cross-sectional view (left) and top view (right) of the first electrode and the second electrode after coating and baking the first photoresist layer in the present invention are completed;

[0021] Figure 4 The cross-sectional view (left) and top view (right) of the dielectric layer after deposition in the present invention;

[0022] Figure 5 The cross-sectional view (left) and top view (right) of the second photoresist layer after exposure / development in the present invention are shown;

[0023] Figure 6 The cross-sectional view (left) and top view (right) of the present invention after coating the second photoresist layer and etching the dielectric layer;

[0024] Figure 7 The cross-sectional view (left) and top view (right) of the present invention after the second photoresist layer is removed;

[0025] Figure 8 The cross-sectional view (left) and top view (right) of the third photoresist layer after exposure / development in the present invention are shown;

[0026] Figure 9 The cross-sectional view (left) and top view (right) of the vapor-deposited third electrode of the present invention;

[0027] Figure 10 The cross-sectional view (left) and top view (right) of the present invention after the third photoresist layer is removed;

[0028] Figure 11 A top view of the dielectric layer etched and exposed outside the third electrode in the present invention;

[0029] Figure 12 It is a top view after removing the first electro-optical resist layer in the present invention;

[0030] Figure 13 For the present invention Figure 12 Cross-sectional view at aa in the middle;

[0031] Figure 14 For the present invention Figure 12 Cross-sectional view at bb in the middle.

[0032] Among them: 1. first electrode, 2. second electrode, 3. first photoresist layer, 4. dielectric layer, 5. second photoresist layer, 6. third photoresist layer, 7. bridge hole, 8. bridge body, 9. bridge pier. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the accompanying drawings.

[0034] See also Figures 1 to 14The present invention provides an embodiment: an air bridge process method, comprising the following steps:

[0035] Step S1: Complete the first electrode 1 and the second electrode 2 on the semiconductor material, and apply the first photoresist layer 3, as shown in FIG. Figure 3 As shown, after exposure / development, baking is performed, and after baking, a dielectric layer 4 is deposited on the entire upper surface; Figure 4 As shown,

[0036] Step S2: Coating a second photoresist layer 5 on the dielectric layer 4 at a position corresponding to the first photoresist layer 3, and after exposure / development, etching the dielectric layer 4 outside the second photoresist layer 5, and then removing the second photoresist layer 5; the cross-sectional view and top view of the second photoresist layer 5 after exposure / development are shown in FIG. Figure 5 The cross-sectional view and top view of the dielectric layer 4 after etching are shown as follows: Figure 6 As shown, the dielectric layer 4 is etched to remove the dielectric layer 4 at the second electrode 2, and the third electrode is subsequently connected to the second electrode 2; the cross-sectional view and top view after the second photoresist layer 5 is removed are shown in FIG. Figure 7 As shown;

[0037] Step S3: Coat a third photoresist layer 6 on the semiconductor material around the positions of the first electrode 1, the second electrode 2 and the position of the bridge hole 7 to be made on the dielectric layer 4. The photoresist is a negative photoresist and is exposed / developed. The cross-sectional view and top view of the exposure / development are shown in FIG. Figure 8 As shown;

[0038] Step S4: Vapor-deposit the third electrode on the entire upper surface, remove the third photoresist layer 6, the dielectric layer 4 under the third photoresist layer 6 where the bridge hole 7 is to be made, and the first photoresist layer 3, and complete the entire air bridge process. Figure 9 The cross-sectional view and top view of the photoresist and the position of the bridge hole 7 to be made after the dielectric layer 4 under the third photoresist layer 6 is removed are shown in FIG. Figure 10 ;at this time Figure 10 The red area in the top view of z is the dielectric layer 4. The subsequent purpose is to remove the dielectric layer 4 in the exposed red area, and then remove the photoresist under the dielectric layer 4; the entire wafer is not coated with photoresist and the entire surface is etched; the etching material is generally SF4 / O2; the photoresist under the dielectric layer 4 is exposed, such as Figure 11 As shown; remove the photoresist, as shown Figure 12 As shown; the entire air bridge process is completed;

[0039] Please continue reading Figures 1 to 14As shown in FIG. 1 , in one embodiment of the present invention, the dielectric layer 4 is deposited using plasma-assisted atomic layer deposition technology, with a deposition temperature below 80°C. Photoresist is not resistant to high temperatures, and the conventional deposition environment temperature is 290°C. In this application, plasma-assisted atomic layer deposition technology is used, which can complete deposition at 80°C. The cross-sectional view and top view of the dielectric layer 4 after deposition are shown in FIG. Figure 4 .

[0040] Please continue reading Figures 1 to 14 As shown, in one embodiment of the present invention, the material used for the dielectric layer 4 is Al2O3, TiO2, Ta2O5, ZrO2, HfO2, SnO2, ZnO, La2O3, V2O5 or SiO2, and the thickness of the dielectric layer 4 is 10nm to 100nm.

[0041] Please continue reading Figures 1 to 14 As shown, in one embodiment of the present invention, the first photoresist layer 3, the second photoresist layer 5, and the third photoresist layer 6 are all made of resin and photosensitizer. The second photoresist layer 5 is thicker than 100 μm, and the third photoresist layer 6 is 4 to 6 μm thick. The typical air bridge thickness is greater than 2.5 μm. In the present invention, the second photoresist layer 5 is set to a thickness of greater than 3 μm to protect the air bridge. This thickness protects the dielectric layer 4, preventing the dielectric layer 4 beneath the third photoresist layer from being etched. The dielectric layer 4 in other areas needs to be etched away.

[0042] Please continue reading Figures 1 to 14 As shown, in one embodiment of the present invention, the material of the third electrode is Ti, Pt or Au, and the thickness of the third electrode is 2um to 4um.

[0043] Please continue reading Figure 8 As shown in one embodiment of the present invention, after exposure / development in step S3, the third photoresist layer 6 at the position of the first electrode 1 and the second electrode 2 forms a regular trapezoidal cross-section. Figure 8 .

[0044] Please continue reading Figure 5 、 Figure 6 、 Figure 13 As shown, in one embodiment of the present invention, the area of ​​the second photoresist layer 5 at the dielectric layer 4 is larger than the area of ​​the upper surface of the air bridge. This is to protect the photoresist under the air bridge and prevent it from being removed when the second photoresist layer 5 is subsequently removed.

[0045] See also Figures 12 to 14The present invention provides another embodiment: an air bridge, comprising an air bridge body and a semiconductor material, wherein a plurality of stacked first electrodes 1 and second electrodes 2 are arranged on the semiconductor material, the air bridge body comprising a bridge body 8 and a bridge pier 9, the bridge pier 9 being arranged on the second electrode 2, the bridge body 8 having a half-mouth-shaped protrusion in the middle, and the bridge pier 9 being connected to both ends, a dielectric layer 4 being in contact with the bridge body 8 being arranged below the bridge body 8, and bridge holes 7 being opened on the left and right sides of the bridge body 8 and the dielectric layer 4.

[0046] Please continue to see Figures 12 to 14 The present invention provides another embodiment: In one embodiment of the present invention, both ends of the dielectric layer 4 are arranged on the second electrode 2 .

[0047] The present invention has the following working principle: the air bridge manufactured by the process method of the present invention has strong pressure resistance in the vertical space and is not easily collapsed, broken or cracked. By adding a dense dielectric layer 4 under the air bridge, the pressure resistance in the vertical space is improved, and the appearance yield of the finished product is improved; two bridge holes 7 are left on the bridge, which not only improves the efficiency of photoresist removal but also improves the bridge's resistance to high-pressure flushing on the horizontal plane. Compared with leaving no holes on the bridge, a narrower bridge deck can be achieved while ensuring the yield; it is beneficial to reduce space and improve integration.

[0048] The above description is only a preferred embodiment of the present invention and should not be understood as limiting the present application. All equivalent changes and modifications made within the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. An air bridge process method, characterized in that: The steps include: Step S1: forming a first electrode and a second electrode on a semiconductor material, coating a first photoresist layer, exposing / developing the material, and baking the material. After baking, a dielectric layer is deposited on the entire upper surface of the material. Step S2: coating a second photoresist layer on the dielectric layer at a position corresponding to the first photoresist layer, and after exposure / development, etching the dielectric layer outside the second photoresist layer, and then removing the second photoresist layer; Step S3, coating a third photoresist layer on the semiconductor material around the positions of the first electrode, the second electrode and the position of the bridge hole to be made on the dielectric layer, wherein the photoresist is a negative photoresist, and performing exposure / development; Step S4: vapor-deposit the third electrode on the entire upper surface, remove the third photoresist layer, the dielectric layer under the third photoresist layer at the location where the bridge hole is to be made, and the first photoresist layer, and complete the entire air bridge process.

2. The air bridge manufacturing method according to claim 1, wherein: The dielectric layer is deposited using plasma-assisted atomic layer deposition technology at a temperature below 80°C.

3. The air bridge manufacturing method according to claim 1, wherein: The material used for the dielectric layer is Al2O3, TiO2, Ta2O5, ZrO2, HfO2, SnO2, ZnO, La2O3, V2O5 or SiO2, and the thickness of the dielectric layer is 10nm to 100nm.

4. The air bridge manufacturing method according to claim 1, wherein: The materials of the first photoresist layer, the second photoresist layer and the third photoresist layer are all composed of resin and photosensitizer. The thickness of the second photoresist layer is greater than 3um, and the thickness of the third photoresist layer is 4-6um.

5. The air bridge manufacturing method according to claim 1, wherein: The material of the third electrode is Ti, Pt or Au, and the thickness of the third electrode is 2um to 4um.

6. The air bridge manufacturing method according to claim 1, wherein: In the step S3 , after exposure / development, the third photoresist layer at the positions of the first electrode and the second electrode forms a regular trapezoidal cross-section.

7. The air bridge manufacturing method according to claim 1, wherein: The area of ​​the second photoresist layer located in the dielectric layer is larger than the upper surface area of ​​the air bridge.

8. An air bridge manufactured by the manufacturing method of claim 1, characterized in that: It includes an air bridge body and a semiconductor material, and a plurality of stacked first electrodes and second electrodes are arranged on the semiconductor material. The characteristic is that the air bridge body includes a bridge body and bridge piers, and the bridge piers are arranged on the second electrode. The middle of the bridge body is raised in a half-mouth shape, and the bridge piers are connected to both ends. A dielectric layer is provided under the bridge body and is in contact with the bridge body. Bridge holes are opened on the left and right sides of the bridge body and the dielectric layer.

9. The air bridge according to claim 8, characterized in that: Both ends of the dielectric layer are arranged on the second electrode.

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