A high frequency chip and its preparation method

Abstract

The invention discloses a high-frequency chip and a preparation method thereof, comprising a baseband chip, wherein a U-shaped hollow groove is provided on the baseband chip, an oscillator chip is integrated inside the baseband chip, and the oscillator chip is formed by performing a photolithography etching process on the positions corresponding to the hollow grooves above and below the baseband chip, so that the thickness of the oscillator chip in the area is thinned, and the thickness of the oscillator chip matches the target frequency; the hollow groove is opened by the photolithography etching process; the baseband chip and the oscillator chip are both rectangular; by opening the U-shaped hollow groove, three of the four side surfaces of the oscillator chip can be in an overhead state, so that only one side surface of the oscillator chip is connected to the baseband chip, thereby reducing the connection area between the oscillator chip and the baseband chip. This arrangement can not only reduce the edge effect of the oscillator chip, but also greatly reduce the oscillation impedance of the oscillator chip, and reduce the resistance of the high-frequency chip product to less than 20Ω.

Description

Technical Field

[0001] The invention belongs to the field of communication technology, and in particular relates to a high-frequency chip and a preparation method thereof. Background Art

[0002] High-frequency chips are the core components of quartz crystal oscillators and are chip components used in high-frequency circuits. High-frequency chips are widely used in electronic devices such as computer motherboards, monitors, hard drives, cameras, etc. They are mainly used to generate the clock frequency signals required for the CPU to execute commands.

[0003] In the current prior art, the connection method between the quartz wafer and the substrate is usually to use conductive glue to connect one side of the quartz wafer to the other side of the substrate. This method can improve the stability of the quartz wafer. However, the method of connecting the quartz wafer and the substrate with conductive glue will increase the starting impedance of the quartz wafer. At the same time, the large connection area between the quartz wafer and the substrate will increase the edge effect of the quartz wafer, resulting in uneven electric field distribution, mechanical stress concentration and reduced heat dissipation performance.

[0004] In the current existing technology, when using a quartz wafer, the quartz wafer needs to be thinned to a thickness that matches the target frequency. The common way to thin the quartz wafer is to grind the quartz wafer with a grinding sheet. Although this method can thin the quartz wafer, it will cause the surface roughness of the quartz wafer to be relatively high, and the use conditions of the grinding sheet are limited. When the frequency exceeds 200MHz (quartz wafer thickness <8um), it is difficult for the grinding sheet to grind the quartz wafer. Summary of the invention

[0005] One of the purposes of the present invention is to solve the problems of increased oscillation impedance of quartz wafers and increased edge effects of quartz wafers in the prior art.

[0006] The second purpose of the present invention is to solve the problem of high surface roughness of quartz wafers and limited use conditions of grinding sheets, and to provide a high-frequency wafer and a preparation method thereof.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A high-frequency chip and a preparation method thereof include a baseband chip, a U-shaped hollow groove is opened on the baseband chip, an oscillator chip is integrated inside the baseband chip, the oscillator chip is formed by performing a photolithography etching process on the positions corresponding to the hollow grooves above and below the baseband chip to reduce the thickness of the corresponding positions of the baseband chip, and the thickness of the oscillator chip matches the target frequency.

[0009] Preferably, the hollow groove is opened by a photolithography etching process.

[0010] Preferably, the baseband chip and the oscillator chip are both rectangular.

[0011] Preferably, the middle parts of the upper surface and the lower surface of the oscillator chip are connected to main electrodes.

[0012] Preferably, positions of the upper surface and the lower surface of the oscillating chip away from the hollow groove are respectively connected to symmetrically arranged secondary electrodes.

[0013] Preferably, a side of the oscillator chip close to the auxiliary electrode is connected to a symmetrically arranged side metal layer, and the corresponding auxiliary electrode is connected to the side metal layer.

[0014] Preferably, the upper and lower surfaces of the baseband chip and the oscillator chip are respectively connected to connection circuits at positions corresponding to the main electrode and the auxiliary electrode, and the connection circuits are connected to the main electrode and the auxiliary electrode.

[0015] Preferably, the main electrode, the auxiliary electrode, the side metal layer and the connecting circuit are integrated, and the circuit coated on the baseband chip is formed by an exposure and etching process.

[0016] Preferably, the two connecting circuits are centrally symmetrical when viewed from a cross-sectional view.

[0017] Preferably, the method for preparing the high frequency chip comprises the following steps:

[0018] S1: A hollow groove is formed on the baseband chip through a photolithography and etching process.

[0019] S2: Form an oscillator chip through a photolithography and etching process.

[0020] S3: Thinning the oscillator chip to a thickness that matches the target frequency.

[0021] S4: Use a coating machine to fully coat the baseband chip and the oscillator chip.

[0022] S5: A main electrode and a secondary electrode are formed through a photolithography and etching process, as well as a connecting circuit and a side metal layer to form a complete circuit.

[0023] Beneficial effects of the present invention:

[0024] By opening a U-shaped hollow groove, the present invention can make three of the four sides of the oscillator chip in an overhead state, so that only one side of the oscillator chip is connected to the baseband chip, thereby reducing the connection area between the oscillator chip and the baseband chip. This setting method can not only reduce the edge effect of the oscillator chip, but also greatly reduce the oscillation impedance of the oscillator chip, thereby reducing the resistance of the high-frequency chip product to less than 20Ω.

[0025] The present invention can effectively avoid the problem of high surface roughness of traditional grinding sheets by thinning the oscillator chip through photolithography and etching process, and can also solve the problem that the quartz chip is difficult to grind when the frequency exceeds 200MHz (quartz chip thickness <8um). BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings.

[0027] Figure 1 is a stereogram of the present invention;

[0028] Figure 2 is a cross-sectional view of the present invention;

[0029] Figure 3 is a perspective view of the other side of the present invention;

[0030] Figure 4 It is an exploded view of the present invention.

[0031] In the figure: 1. Baseband chip; 2. Hollow groove; 3. Oscillator chip; 4. Main electrode; 5. Sub-electrode; 6. Side metal layer; 7. Connection circuit. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] See also Figure 1 - Figure 4 As shown, a high-frequency chip and a preparation method thereof include a baseband chip 1 for providing a chip basic structure and a chip angle.

[0034] A U-shaped hollow groove 2 is provided on the baseband chip 1, and an oscillating chip 3 is integrated inside the baseband chip 1. The oscillating chip 3 is formed by performing a photolithography etching process on the positions corresponding to the hollow groove 2 above and below the baseband chip 1, so that the thickness of the corresponding position of the baseband chip 1 is thinned, and the thickness of the oscillating chip 3 matches the target frequency; the hollow groove 2 is provided by the photolithography etching process; the baseband chip 1 and the oscillating chip 3 are both rectangular; the middle of the upper surface and the lower surface of the oscillating chip 3 are connected to the main electrode 4; the upper surface and the lower surface of the oscillating chip 3 are respectively connected to symmetrical A secondary electrode 5 is arranged; a symmetrically arranged side metal layer 6 is connected to the side of the oscillating chip 3 close to the secondary electrode 5, and the corresponding secondary electrode 5 is connected to the side metal layer 6; the upper and lower surfaces of the baseband chip 1 and the oscillating chip 3 corresponding to the positions of the main electrode 4 and the secondary electrode 5 are respectively connected with a connecting circuit 7, and the connecting circuit 7 is connected to the main electrode 4 and the secondary electrode 5; the main electrode 4, the secondary electrode 5, the side metal layer 6 and the connecting circuit 7 are arranged as a whole, and the circuit coated on the baseband chip 1 is formed by an exposure and etching process; the two connecting circuits 7 are centrally symmetrical when observed from the cross-sectional view.

[0035] The baseband chip 1 is rectangular. Setting the baseband chip 1 to be rectangular has the following advantages: 1. The structure is relatively simple and regular, and the shape and size are relatively fixed and easy to control, which can more easily achieve large-scale and efficient production, facilitate quality control during manufacturing and processing, reduce production costs, and improve product quality and consistency;

[0036] Second, it can be more easily matched with packaging materials, thereby simplifying the packaging process and reducing packaging costs;

[0037] 3. It can use space more effectively within the same packaging area, improve packaging density, and reduce the volume and weight of the entire electronic system;

[0038] Fourth, it is conducive to heat dissipation and can effectively transfer heat to the surrounding environment, preventing the baseband chip 1 from overheating and extending the service life.

[0039] A U-shaped hollow groove 2 is provided on the baseband chip 1. By providing the U-shaped hollow groove 2, three of the four sides of the oscillator chip 3 can be in an overhead state, so that only one side of the oscillator chip 3 is connected to the baseband chip 1, thereby reducing the connection area between the oscillator chip 3 and the baseband chip 1. This setting method can not only reduce the edge effect of the oscillator chip 3, but also greatly reduce the oscillation impedance of the oscillator chip 3, thereby reducing the resistance of the high-frequency chip product to less than 20Ω.

[0040] The hollow groove 2 is opened by a photolithography and etching process.

[0041] An oscillator chip 3 is integrated inside the baseband chip 1 , and the oscillator chip 3 is used to provide an original oscillator frequency.

[0042] The oscillating chip 3 is formed by performing photolithography etching on the positions corresponding to the hollow grooves 2 above and below the baseband chip 1 to reduce the thickness of the corresponding positions of the baseband chip 1. The thickness of the oscillating chip 3 matches the target frequency.

[0043] It is worth noting here that: in the prior art, the method for thinning the oscillator chip 3 is to grind it through a grinding sheet. Now, the method for thinning the oscillator chip 3 is changed, and the oscillator chip 3 is thinned by a photolithography etching process. Comparing the two methods, thinning the oscillator chip 3 through a photolithography etching process can effectively avoid the problem of high surface roughness of traditional grinding sheets, and at the same time solve the problem that the quartz wafer is difficult to grind when the frequency exceeds 200MHz (quartz wafer thickness <8um).

[0044] The oscillating chip 3 is rectangular. Setting the oscillating chip 3 to be rectangular has the following advantages: 1. It can vibrate in a more stable manner, thereby reducing unnecessary vibration modes and improving the frequency stability of the output signal;

[0045] Second, it can more easily achieve the required vibration amplitude and frequency, thereby improving the starting efficiency;

[0046] 3. It can minimize friction and damping during vibration, thereby reducing energy loss, helping to reduce energy loss during vibration and improve efficiency.

[0047] The middle of the upper surface and the lower surface of the oscillating chip 3 are both connected with main electrodes 4, and the main electrodes 4 are used to receive the oscillating frequency.

[0048] The upper and lower surfaces of the oscillating chip 3 are connected to symmetrically arranged auxiliary electrodes 5 at positions away from the hollow grooves 2. The auxiliary electrodes 5 are used to provide a conductive adhesive bonding site and can be connected to an external circuit through a base to form a passage.

[0049] A symmetrically arranged side metal layer 6 is connected to one side of the oscillating chip 3 close to the auxiliary electrode 5 , and the corresponding auxiliary electrode 5 is connected to the side metal layer 6 . The side metal layer 6 is used to connect the auxiliary electrodes 5 on the upper and lower surfaces of the oscillating chip 3 .

[0050] The upper and lower surfaces of the baseband chip 1 and the oscillator chip 3 are respectively connected to the positions of the main electrode 4 and the auxiliary electrode 5, and the connecting circuit 7 is connected to the main electrode 4 and the auxiliary electrode 5. The connecting circuit 7 is used to connect the main electrode 4, the auxiliary electrode 5 and the side metal layer 6 to form a passage.

[0051] The main electrode 4, the secondary electrode 5, the side metal layer 6 and the connecting circuit 7 are integrally arranged, and the circuit coated on the baseband chip 1 is formed by an exposure and etching process. This arrangement can obtain the following advantages: First, there is no need to perform coating treatment multiple times in order to prepare different patterns, which simplifies the production process and improves production efficiency;

[0052] Second, during multiple coating processes, there will be a tiny error in each coating. Multiple coatings will cause the error to accumulate, resulting in inaccurate patterns. One-time full coating and exposure etching can reduce the cumulative error and improve accuracy and consistency.

[0053] 3. It ensures the uniformity and integrity of the pattern, helps optimize the performance of the circuit, and can increase transmission speed, reduce loss and enhance anti-interference capabilities.

[0054] The two connecting circuits 7 are centrally symmetrical when observed from the cross-sectional view. This arrangement can make the heat in the circuit evenly distributed, reduce the generation of hot spots, improve the thermal stability of the baseband chip 1 and the oscillator chip 3, and extend the service life of the baseband chip 1 and the oscillator chip 3.

[0055] The performance of the MESA sheet products in the prior art was tested by selecting different frequency points, and the results are shown in Table 1:

[0056] Table 1

[0057] Frequency 100MHz 125MHz 180MHz Serial number MESA sheet / Ω MESA sheet / Ω MESA sheet / Ω 1 20.8 19.8 12.7 2 23.0 17.4 12.6 3 23.7 20.5 10.1 4 21.5 19.2 13.6 5 22.7 17.2 10.5

[0058] The performance of the high frequency chip product of the present invention was tested by selecting different frequency points, and the results are shown in Table 2:

[0059] Table 2

[0060] Frequency 100MHz 125MHz 180MHz Serial number High frequency chip / Ω High frequency chip / Ω High frequency chip / Ω 1 18.9 12.0 8.5 2 16.4 12.8 8.4 3 15.7 15.5 7.9 4 18.4 13.2 8.6 5 18.3 14.6 8.2

[0061] By comparing Table 1 with Table 2, it can be seen that under different frequency point tests, the resistance of the high-frequency chip product in the present invention is lower than the resistance of the MESA chip product in the prior art.

[0062] The method for preparing a high frequency chip comprises the following steps:

[0063] S1: Opening a hollow groove 2 on the baseband wafer 1 by photolithography and etching process;

[0064] S2: forming an oscillator chip 3 by photolithography and etching process;

[0065] S3: thinning the oscillator chip 3 to a thickness matching the target frequency;

[0066] S4: Use a coating machine to fully coat the baseband chip 1 and the oscillator chip 3;

[0067] S5: A main electrode 4 and a secondary electrode 5 are formed through a photolithography and etching process, as well as a connecting circuit 7 and a side metal layer 6 to form a complete circuit.

[0068] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0069] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high frequency chip, comprising a baseband chip (1), characterized in that: The baseband chip (1) is provided with a U-shaped hollow groove (2), and an oscillating chip (3) is integrated inside the baseband chip (1). The oscillating chip (3) is formed by performing a photolithography etching process on the positions above and below the baseband chip (1) corresponding to the hollow groove (2), so as to reduce the thickness of the corresponding positions of the baseband chip (1), and the thickness of the oscillating chip (3) matches the target frequency.

2. A high frequency chip according to claim 1, characterized in that: The hollow groove (2) is opened by a photolithography and etching process.

3. A high frequency chip according to claim 2, characterized in that: The baseband chip (1) and the oscillator chip (3) are both rectangular.

4. A high frequency chip according to claim 3, characterized in that: The middle parts of the upper surface and the lower surface of the oscillating chip (3) are both connected to main electrodes (4).

5. A high frequency chip according to claim 4, characterized in that: The upper surface and the lower surface of the oscillating chip (3) are respectively connected to symmetrically arranged secondary electrodes (5) at positions away from the hollow grooves (2).

6. A high frequency chip according to claim 5, characterized in that: A side metal layer (6) arranged symmetrically is connected to a side of the oscillating chip (3) close to the auxiliary electrode (5), and a corresponding auxiliary electrode (5) is connected to the side metal layer (6).

7. A high frequency chip according to claim 6, characterized in that: The upper and lower surfaces of the baseband chip (1) and the oscillating chip (3) are respectively connected to connection circuits (7) at positions corresponding to the main electrode (4) and the auxiliary electrode (5), and the connection circuits (7) are connected to the main electrode (4) and the auxiliary electrode (5).

8. A high frequency chip according to claim 7, characterized in that: The main electrode (4), the auxiliary electrode (5), the side metal layer (6) and the connecting circuit (7) are arranged as a whole, and are formed by coating the circuit on the baseband chip (1) through an exposure and etching process.

9. A high frequency chip according to claim 8, characterized in that: The two connecting circuits (7) are centrally symmetrical when viewed from a cross-sectional view.

10. A method for preparing a high-frequency chip, applicable to a high-frequency chip as claimed in any one of claims 1 to 9, characterized in that: The method for preparing a high frequency chip comprises the following steps: S1: Opening a hollow groove (2) on a baseband chip (1) by a photolithography and etching process; S2: forming an oscillator chip (3) by photolithography and etching process; S3: thinning the oscillator chip (3) to a thickness matching the target frequency; S4: using a coating machine to coat the baseband chip (1) and the oscillator chip (3) in their entirety; S5: A main electrode (4) and a secondary electrode (5) are formed through a photolithography and etching process, as well as a connecting circuit (7) and a side metal layer (6) to form a complete circuit.

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