Chip structure and fabrication method
By using integrally molded metal or polymer materials to create the chip cavity structure, the problems of strict material selection and high cost in the existing technology are solved, thereby improving stability and yield, and reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WUHAN YUNLING OPTOELECTRONICS CO LTD
- Filing Date
- 2025-03-31
- Publication Date
- 2026-08-04
AI Technical Summary
Existing chip cavity structure materials are subject to strict selection, are costly, and are difficult to effectively protect the device from external environmental influences, affecting the device's stability and yield.
It adopts an integral cavity structure with the same substrate and cover plate materials, and uses metal, insulating or polymer materials to create the chip structure in combination with photolithography. The cavity can be filled with or not filled with insulating material, which simplifies the process and reduces costs.
This improved the stability and yield of the devices, reduced production costs, and simplified the manufacturing process.
Smart Images
Figure CN120432443B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optical communication technology, specifically to a chip structure and its fabrication method. Background Technology
[0002] In semiconductor devices, the active regions of some chips require a cavity environment to ensure normal operation. The cavity structure can reduce losses introduced by parasitic effects, provide better radio frequency performance and a lower dielectric constant. Furthermore, the cavity structure can protect the microstructure from external environmental influences, improving device stability, reliability, and yield. Existing chip cavity structures are shown below. Figure 1 The substrate and cover plate are each composed of two or more materials, and the properties of these two materials are subject to strict requirements. Material selection is highly limited and costly. Typically, two layers of photosensitive thin film material are used to form the substrate and the cavity cover plate, respectively, creating a cavity structure on the chip surface. The thin film used as the cavity cover plate must also match the properties of the thin film material used as the substrate. Its material properties, such as elastic modulus, coefficient of thermal expansion, and photosensitive characteristics, are all subject to strict requirements, resulting in significant material selection limitations and high material costs. Summary of the Invention
[0003] The purpose of this invention is to provide a chip structure and its manufacturing method, which can at least solve some of the defects in the prior art.
[0004] To achieve the above objectives, the present invention provides the following technical solution: a chip structure, including a cavity structure for protecting the area to be protected of the chip body, the cavity structure being a frame-shaped substrate and a cover plate disposed on the substrate, the substrate and the cover plate being integrally formed and made of the same material.
[0005] Furthermore, the chip body includes a ridge waveguide structure, the ridge waveguide structure having an active region, and the cavity structure located above the active layer.
[0006] Furthermore, the substrate and the cover plate are made of one or more of the following materials: metal, insulating material, or polymer material.
[0007] Furthermore, the cavity of the cavity structure is filled with insulating material or polymer material.
[0008] Furthermore, the insulating material includes Si, SiO2, or SiN. x The polymer material includes BCB or polyimide, and the insulating material filling the cavity in the cavity structure also includes photoresist.
[0009] This invention provides another technical solution: a method for fabricating a chip structure, comprising the following steps: The ridge waveguide is fabricated on the wafer surface using a combination of dry and wet photolithography processes. An electrical injection window is fabricated on the ridge waveguide; Fabricate metal electrodes on the wafer surface; A cavity structure is fabricated above the active region of the ridge waveguide; When manufacturing the cavity structure, the base and cover plate of the cavity structure are integrally formed and made of the same material.
[0010] Furthermore, the cavity structure has no filling material or no filling material.
[0011] Furthermore, when there is no filling material in the cavity structure, a photolithography process is used to retain the photoresist in the active layer area and sputter a metal seed layer without removing the photoresist; the photoresist is then homogenized again, and a photolithography process is used to remove the photoresist in the active layer area to expose the metal seed layer; the metal layer is thickened using electroplating or chemical plating; after removing the photoresist, the metal seed layer, the metal layer, and the metal electrode form the cavity structure.
[0012] Furthermore, when there is no filling material in the cavity structure, the photoresist in the active layer area is retained using photolithography; the photoresist is then homogenized again, using BCB or polyimide to wrap around the photoresist in the active layer area on both sides, exposing the photoresist on both sides of the light-emitting end and the backlight end; after removing the photoresist, the BCB and the metal electrode form the cavity structure.
[0013] Furthermore, when the cavity structure contains a filling material, the BCB photoresist in the active layer region is retained using a photolithography process; after curing, SiO2 is deposited on the BCB photoresist, and the SiO2 and the metal electrode form the cavity structure, with BCB as the filling material. Alternatively, when the cavity structure contains a filling material, the insulating layer in the active layer region is retained; metal is deposited on the surface of the insulating material Si, and the metal deposited on the insulating layer and the metal electrode form the cavity structure, with Si as the filling material.
[0014] Compared with the prior art, the beneficial effects of the present invention are: the base and cover plate of the cavity are made of the same material and are integrally formed, which can protect the functional structure of the device from the influence of the external environment, improve the stability, reliability and yield of the device, and at the same time, the process of the present application is simple and the production cost is low. Attached Figure Description
[0015] Figure 1 It uses a traditional chip structure; Figure 2 This is a schematic diagram of the structure after the metal electrode is fabricated, according to a method for fabricating a chip structure provided in Embodiment 1 of the present invention. Figure 3 for Figure 2 A cross-sectional view along the AA direction; Figure 4This is a schematic diagram of the photoresist structure in the active layer region of a chip structure fabrication method provided in Embodiment 1 of the present invention. Figure 5 for Figure 4 A cross-sectional view along the AA direction; Figure 6 This is a schematic diagram of the metal seed layer fabrication method with adhesive provided in Embodiment 1 of the present invention. Figure 7 for Figure 6 A cross-sectional view along the AA direction; Figure 8 This is a schematic diagram of the photoresist structure outside the active layer region in a chip structure fabrication method provided in Embodiment 1 of the present invention. Figure 9 for Figure 8 A cross-sectional view along the AA direction; Figure 10 This is a schematic diagram of a metal-thickened, adhesive-coated structure provided in Embodiment 1 of the present invention for a chip structure fabrication method. Figure 11 for Figure 10 A cross-sectional view along the AA direction; Figure 12 This is a schematic diagram of the cavity formation during the removal of adhesive in a chip structure fabrication method according to Embodiment 1 of the present invention. Figure 13 for Figure 12 A cross-sectional view along the AA direction; Figure 14 This is a schematic diagram of the BCB or PI homogenized structure of a chip structure fabrication method provided in Embodiment 2 of the present invention. Figure 15 for Figure 4 A cross-sectional view along the AA direction; Figure 16 This is a schematic diagram of the cavity formed after removing the adhesive in a chip structure fabrication method according to Embodiment 2 of the present invention; Figure 17 for Figure 16 A cross-sectional view along the AA direction; Figure 18 This is a schematic diagram of the BCB or PI structure after curing, according to a chip structure fabrication method provided in Embodiment 3 of the present invention. Figure 19 for Figure 18 A cross-sectional view along the AA direction; Figure 20 This is a schematic diagram of a cavity-filled BCB or PI structure for a chip structure fabrication method provided in Embodiment 3 of the present invention; Figure 21 for Figure 20A cross-sectional view along the AA direction; In the attached diagram, the following labels are used: 1-ridge waveguide; 2-metal electrode; 3-photoresist; 4-metal seed layer; 5-metal thickening; 6-BCB or PI; 7-substrate; 8-cavity cover plate; 9-SiO2. Detailed Implementation
[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0017] Please see Figures 2 to 21 This invention provides a chip structure including a cavity structure for protecting a protected area of the chip body. The cavity structure is a frame-shaped substrate and a cover plate disposed on the substrate. The substrate and the cover plate are integrally formed and made of the same material. Preferably, the chip body includes a ridge waveguide 1 structure, the ridge waveguide 1 structure has an active region, and the cavity structure is located above the active layer. In this embodiment, the substrate and cover plate of the cavity structure are made of the same material and are integrally formed, which can protect the functional structure of the device from the influence of the external environment, improve the stability, reliability and yield of the device, and at the same time, the process of this application is simple and the production cost is low. Specifically, the cavity structure is located above the active region or in the protected area of the chip surface.
[0018] Please see Figures 2 to 21 The cavity substrate and cover plate are made of metallic materials, or Si (silicon), SiO2 (silicon dioxide), SiN. x Insulating materials, or polymer materials such as BCB (benzocyclobutene resin) and Polyimide (PI), can also be composed of combinations of the above materials.
[0019] Please see Figures 2 to 21 The cavity structure may or may not be filled. Preferably, it is filled with photoresist or Si (silicon), SiO2 (silicon dioxide), or SiN. x After depositing cavity material on the insulating material, remove the photoresist or Si (silicon), SiO2 (silicon dioxide), or SiN under the cavity. x Insulating materials such as photoresist, Si (silicon), SiO2 (silicon dioxide), and SiN are used to form unfilled cavities. Preferably, these cavities are formed using photoresist, Si (silicon), SiO2 (silicon dioxide), or SiN. x After depositing cavity material on insulating materials or polymer materials such as BCB (benzocyclobutene resin) and Polyimide (PI), the material inside the cavity is retained to form a cavity filled with material.
[0020] This invention also provides a method for fabricating a chip structure, comprising the following steps: fabricating the ridge waveguide 1 on the wafer surface using a combination of dry and wet photolithography; fabricating an electrical injection window on the ridge waveguide 1; fabricating a metal electrode 2 on the wafer surface; fabricating a cavity structure above the active region of the ridge waveguide 1; and fabricating the cavity structure such that the substrate and cover plate of the cavity structure are integrally formed and made of the same material.
[0021] Preferably, the cavity structure has no filling material or has a filling material. When the cavity structure has no filling material, photolithography is used to retain the photoresist in the active layer area, and a metal seed layer is sputtered without removing the photoresist; then, photolithography is used again to remove the photoresist in the active layer area, exposing the metal seed layer; the metal layer is thickened using electroplating or chemical plating; after removing the photoresist, the metal seed layer, the metal layer, and the metal electrode 2 form the cavity structure. When the cavity structure has no filling material, photolithography is used to retain the photoresist in the active layer area; then, photolithography is used again, using BCB or Polyimide to wrap around the photoresist in the active layer area on both sides, exposing the photoresist on both sides of the light-emitting end and the backlight end; after removing the photoresist, BCB and the metal electrode 2 form the cavity structure. When the cavity structure has a filling material, photolithography is used to retain the BCB photoresist in the active layer area; after curing, SiO2 is deposited on the BCB photoresist, and the SiO2 and the metal electrode 2 form the cavity structure, with BCB as the filling material. When the cavity structure contains a filling material, the insulating layer material Si of the active layer region is retained; metal is deposited on the insulating layer material Si, and the metal deposited on the insulating layer Si and the metal electrode 2 form the cavity structure, with Si as the filling material.
[0022] The following are the specific implementation methods: Example 1:
[0023] Ridge waveguides are fabricated on the wafer surface using a combination of photolithography processes, both dry and wet methods. Next, an electrical injection window is fabricated on the ridge waveguide; Metal electrode 2 is fabricated on the wafer surface, and after peeling, it is seen... Figure 2 and Figure 3 ; Using photolithography, the photoresist 3 in the active layer region is retained, see... Figure 4 and Figure 5 Sputtered metal seed layer 4, without removing adhesive. Figure 6 and Figure 7 ; After re-coating, the photoresist in the active layer area is removed using photolithography, exposing the metal seed layer 4. (See...) Figure 8 and Figure 9 ; The metal layer 5 is thickened using electroplating or chemical plating processes, see... Figure 10 and Figure 11 (Electroplating and electroless plating processes do not deposit metal on photoresist). After degumming, the metal seed layer 4, together with the metal layer 5 and the metal electrode 2, forms a cavity structure, as shown in the figure. Figure 12 Figure 13; Finally, the chip is thinned, sputtered, and alloyed to complete the chip fabrication process. Example 2:
[0024] Ridge waveguides are fabricated on the wafer surface using a combination of photolithography processes, both dry and wet methods. Next, an electrical injection window is fabricated on the ridge waveguide; Metal electrodes are fabricated on the wafer surface, and after peeling, the following is observed: Figure 2 and Figure 3 ; Using photolithography, the photoresist 3 in the active layer region is retained, see... Figure 4 and Figure 5 ; For the second photoresist coating, use photosensitive BCB (benzocyclobutene resin) or PI (polyimide) 6 to wrap around the active layer area on both sides, exposing the photoresist 3 on both sides of the light end and the backlight end, see [reference]. Figure 14 and Figure 15 ; After the adhesive is removed, BCB 6 forms a cavity structure with the metal electrode 2, see... Figure 16 and Figure 17 ; After the BCB adhesive is cured, it is thinned, sputtered, and alloyed to complete the chip fabrication. Example 3:
[0025] Ridge waveguides are fabricated on the wafer surface using a combination of photolithography processes, both dry and wet methods. Next, an electrical injection window is fabricated on the ridge waveguide; Metal electrode 2 is fabricated on the wafer surface, and after peeling, it is seen... Figure 2 and Figure 3 ; Using photolithography, photosensitive BCB (benzocyclobutene resin) photoresist 6 was used to retain the active layer region. After curing, the results are shown below. Figure 18 and Figure 19 SiO2 9 was deposited on BCB photoresist. SiO2 9 and metal electrode 2 formed a cavity structure, filled with BCB. (See...) Figure 20 and Figure 21 ; Finally, the chip is thinned, sputtered, and alloyed to complete the chip fabrication process.
[0026] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for fabricating a chip structure, characterized in that, Includes the following steps: Ridge waveguides are fabricated on the wafer surface using a combination of photolithography processes, both dry and wet methods. An electrical injection window is fabricated on the ridge waveguide; Fabricate metal electrodes on the wafer surface; A cavity structure is fabricated above the active region of the ridge waveguide; When fabricating the cavity structure, the base and cover plate of the cavity structure are integrally formed and made of the same material to protect the functional structure of the device. The cavity structure has no filling material or is filled with a filling material. When there is no filling material in the cavity structure, the photoresist in the active layer area is retained by photolithography, and a metal seed layer is sputtered without removing the photoresist. The photoresist is then homogenized again, and a photolithography process is used to remove the photoresist in the active layer area, exposing the metal seed layer. Thickening of the metal layer is achieved using electroplating or chemical plating processes; After the adhesive is removed, the metal seed layer, along with the metal layer and the metal electrode, forms the cavity structure. When there is no filling material in the cavity structure, the photoresist in the active layer area is retained by photolithography; the photoresist is then homogenized again, using BCB or polyimide to wrap the photoresist in the active layer area on both sides, exposing the photoresist on both sides of the light-emitting end and the backlight end. After the adhesive is removed, BCB and the metal electrode form the cavity structure described above. When the cavity structure contains a polymer material as the filling material, a photolithography process is used to retain the BCB photoresist in the active layer region. After curing, SiO2 is deposited on the BCB photoresist, and the SiO2 and the metal electrode form the cavity structure, with BCB as the filling material. Alternatively, when the cavity structure contains an insulating material as the filling material, the insulating material Si in the active layer region is retained, and metal is deposited on the surface of the insulating material Si. The metal deposited on the insulating layer and the metal electrode form the cavity structure, with Si as the filling material.
2. A chip structure, characterized in that: The chip structure is fabricated using the method described in claim 1, including a cavity structure for protecting the area to be protected of the chip body, the cavity structure being a frame-shaped substrate and a cover plate disposed on the substrate, the substrate and the cover plate being integrally formed and made of the same material.
3. The chip structure as described in claim 2, characterized in that: The chip body includes a ridge waveguide structure, the ridge waveguide structure has an active region, and the cavity structure is located above the active layer.
4. The chip structure as described in claim 2, characterized in that: The substrate and the cover plate are made of one or more of the following materials: metal, insulating material, or polymer material.
5. The chip structure as described in claim 2, characterized in that: The cavity of the cavity structure is filled with insulating material or polymer material.
6. The chip structure as described in claim 4 or 5, characterized in that: The insulating material includes Si, SiO2, or SiN. x The polymer material includes BCB or polyimide, and the insulating material filling the cavity in the cavity structure also includes photoresist.