Three-dimensional inductor and manufacturing method thereof

Abstract

The invention discloses a three-dimensional inductor and a manufacturing method thereof, and belongs to the field of inductor manufacturing. The three-dimensional inductor comprises: a composite carrier composed of silicon and glass; the cavity is positioned in the glass; the suspended three-dimensional through hole structure penetrates through the glass; metal circuits are arranged on the upper surface and the lower surface of the composite carrier and form a three-dimensional spiral inductance coil through the suspended three-dimensional through hole structure. According to the three-dimensional inductor, the glass cavity is formed in the inductor area, the silicon and glass composite carrier and the suspended three-dimensional through hole structure are adopted, the low-roughness through holes are formed in combination with silicon dry etching, and metallization wiring is conducted, so that the problem that the quality factor (Q value) of a traditional three-dimensional inductor is low due to substrate loss and conductor loss is solved; and the Q value of the three-dimensional inductor is effectively improved.

Description

Technical Field

[0001] This invention relates to a three-dimensional inductor and its manufacturing method, belonging to the field of inductor manufacturing. Background Technology

[0002] Inductors are essential components in integrated circuits, playing a crucial role in switching power supplies and radio frequency circuits. As the integration density of integrated circuits increases, the feature size of semiconductor devices is reaching its physical limits. To further improve performance and integration density, researchers have begun integrating chips in three dimensions. Three-dimensional inductors occupy a smaller area than planar inductors, significantly increasing packaging density and inductance density per unit area. However, inductors typically require a substrate, and conductor and substrate losses make it difficult to achieve a high quality factor for three-dimensional inductors.

[0003] To address the aforementioned issues, several solutions have been proposed in the industry. Patent CN120183846A discloses a three-dimensional inductor and its manufacturing method. This solution utilizes a three-dimensional inductor, but the low Q-value remains a problem. Patent CN119401966A discloses an integrated passive device filter based on TGV technology. This solution uses a glass substrate to realize the three-dimensional inductor; however, due to dielectric losses in the glass substrate and the high surface roughness of TGV, the low Q-value still persists. Summary of the Invention

[0004] To address the problem of relatively low Q-values ​​in existing three-dimensional inductors, this invention provides a three-dimensional inductor and its manufacturing method, the technical solution of which is as follows:

[0005] This invention provides a three-dimensional inductor, comprising:

[0006] A composite carrier composed of silicon and glass;

[0007] The cavity located within the glass;

[0008] A suspended three-dimensional through-hole structure penetrating the glass;

[0009] The metal lines disposed on the upper and lower surfaces of the composite carrier form a three-dimensional spiral inductor coil through the suspended three-dimensional through-hole structure.

[0010] Optionally, the cavity height ranges from 150μm to 600μm.

[0011] Optionally, the material of the metal circuit is copper or gold.

[0012] Optionally, in the three-dimensional through-hole structure, each through-hole is a trapezoidal through-hole.

[0013] Optionally, the suspended three-dimensional through-hole structure is formed by silicon dry etching.

[0014] Optionally, the glass is quartz glass.

[0015] Optionally, the three-dimensional spiral inductor has a Q value ≥ 80 in the range of 3.11 GHz to 7.93 GHz.

[0016] The present invention also provides a method for manufacturing a three-dimensional inductor, comprising:

[0017] (1) A "U" shaped groove is etched on the silicon substrate;

[0018] (2) The groove is filled using a glass reflow process;

[0019] (3) Dry etching is performed on the silicon wafer located in the middle of the groove to form blind holes, and the blind holes are metallized.

[0020] (4) Fabricate metal lines on the front side of the silicon carrier;

[0021] (5) Grind the back side of the silicon carrier so that the back side is flush with the bottom of the glass medium;

[0022] (6) A metal circuit is fabricated on the back side of the silicon carrier, forming a three-dimensional spiral inductor coil with the metal circuit on the front side and the metallized through-hole.

[0023] (7) The silicon carrier of the inductor region is removed by dry etching to form a glass cavity, and the three-dimensional spiral inductor coil is located in the glass cavity.

[0024] Optionally, step (1) involves forming a groove on the silicon carrier by dry etching.

[0025] Optionally, step (2) may also include treating the surface by chemical mechanical polishing.

[0026] The beneficial effects of this invention are:

[0027] This invention solves the problem of low quality factor (Q value) caused by substrate and conductor losses in traditional three-dimensional inductors by setting a glass cavity in the inductor region, using a silicon and glass composite carrier and a suspended three-dimensional through-hole structure. Air has the lowest dielectric loss. Combined with silicon dry etching to form low-roughness through-holes and metallized wiring, this invention effectively improves the Q value of three-dimensional inductors. Experiments show that when using trapezoidal through-holes and a glass thickness of 230μm, the Q value of the quartz glass three-dimensional spiral inductor can reach above 80 in the range of 3.11GHz-7.93GHz, and the inductance of the 3-turn inductor is 3.91nH@5GHz. Further introducing an air cavity structure on the glass substrate can further improve the inductor Q value, increasing the peak Q value from 92 to 96.7, and further expanding the frequency range of Q value above 80 to 2.61-9.27GHz. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a cross-sectional view of the structure of the three-dimensional inductor of the present invention.

[0030] Figure 2 This is a perspective view of the three-dimensional inductor of the present invention.

[0031] Figure 3 This is a schematic diagram of the through-hole shape of the three-dimensional inductor of the present invention.

[0032] Figure 4 This is a simulation diagram of the inductance value of the three-dimensional inductor in Embodiment 1 of the present invention.

[0033] Figure 5 This is a simulation diagram of the quality factor of the three-dimensional inductor in Embodiment 1 of the present invention.

[0034] Figure 6 This is a flowchart of the manufacturing process of the three-dimensional structure inductor of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0036] Example 1:

[0037] This embodiment provides a three-dimensional inductor, such as Figure 1 As shown, it includes: a composite carrier made of silicon and glass materials, a glass cavity, a suspended three-dimensional through-hole structure, and metal circuitry.

[0038] The glass material is located in the middle of the silicon material, and there is a cavity in the middle of the glass material. A suspended three-dimensional through-hole structure is located inside the glass cavity. Metal lines are distributed on the upper and lower surfaces of the composite carrier. These metal lines and the suspended three-dimensional through-hole structure form a three-dimensional spiral inductor coil, such as... Figure 2 As shown.

[0039] The material of the metal circuit can be copper or gold.

[0040] The height of the glass cavity ranges from 150μm to 600μm, preferably 230μm.

[0041] like Figure 3 As shown, in the suspended three-dimensional through-hole structure of this embodiment, each through-hole adopts a trapezoidal through-hole. Experiments have shown that when trapezoidal through-holes are used and the glass thickness is 230μm, the Q value of the quartz glass three-dimensional spiral inductor can reach more than 80 in the range of 3.11GHz-7.93GHz, and the inductance of the 3-turn inductor is 3.91nH@5GHz.

[0042] Further introducing an air cavity structure on the glass substrate can improve the Q value of the inductor, increasing the peak Q value from 92 to 96.7, and further expanding the frequency range with a Q value above 80 to 2.61-9.27 GHz.

[0043] Example 2:

[0044] This embodiment provides a method for manufacturing a three-dimensional inductor, such as Figure 6 As shown, the process includes the following steps:

[0045] (1) A "U-shaped" groove is formed on a silicon substrate by dry etching;

[0046] (2) The grooves are filled using a glass reflow process and the surface is chemically and mechanically ground.

[0047] (3) Dry etching is performed on the silicon wafer located in the middle of the groove to form blind holes, and the blind holes are metallized.

[0048] (4) Fabricate metal circuits on the front side of the silicon substrate;

[0049] (5) Grind the back side of the silicon carrier so that the back side is flush with the bottom of the glass medium;

[0050] (6) A metal circuit is fabricated on the back side of the silicon carrier, and a three-dimensional spiral inductor coil is formed together with the metal circuit on the front side and the metallized via (blind vias are obtained by grinding the back side of the silicon carrier).

[0051] (7) The silicon carrier of the inductor region is removed by dry etching to form a glass cavity, and the three-dimensional spiral inductor coil is located in the glass cavity.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-dimensional inductor, characterized in that, The three-dimensional inductor includes: A composite carrier composed of silicon and glass; The cavity located within the glass; A suspended three-dimensional through-hole structure penetrating the glass; The metal lines disposed on the upper and lower surfaces of the composite carrier form a three-dimensional spiral inductor coil through the suspended three-dimensional through-hole structure.

2. The three-dimensional inductor according to claim 1, characterized in that, The cavity height ranges from 150μm to 600μm.

3. The three-dimensional inductor according to claim 1, characterized in that, The material of the metal circuit is copper or gold.

4. The three-dimensional inductor according to claim 1, characterized in that, In the three-dimensional through-hole structure, each through-hole is a trapezoidal through-hole.

5. The three-dimensional inductor according to claim 1, characterized in that, The suspended three-dimensional through-hole structure is formed by silicon dry etching.

6. The three-dimensional inductor according to claim 1, characterized in that, The glass is quartz glass.

7. The three-dimensional inductor according to claim 1, characterized in that, The three-dimensional spiral inductor has a Q value ≥ 80 in the range of 3.11 GHz to 7.93 GHz.

8. A method for manufacturing a three-dimensional inductor, characterized in that, The method includes: (1) A "U" shaped groove is etched on the silicon substrate; (2) The groove is filled using a glass reflow process; (3) Dry etching is performed on the silicon wafer located in the middle of the groove to form blind holes, and the blind holes are metallized. (4) Fabricate metal lines on the front side of the silicon carrier; (5) Grind the back side of the silicon carrier so that the back side is flush with the bottom of the glass medium; (6) A metal circuit is fabricated on the back side of the silicon carrier, forming a three-dimensional spiral inductor coil with the metal circuit on the front side and the metallized through-hole. (7) The silicon carrier of the inductor region is removed by dry etching to form a glass cavity, and the three-dimensional spiral inductor coil is located in the glass cavity.

9. The method for manufacturing a three-dimensional inductor according to claim 8, characterized in that, Step (1) A groove is formed on the silicon substrate by dry etching.

10. The method for manufacturing a three-dimensional inductor according to claim 8, characterized in that, Step (2) also includes treating the surface by chemical mechanical polishing.

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