Adjustable impedance matcher applied to PVD (Physical Vapor Deposition) pre-cleaning process

Abstract

The utility model relates to an adjustable impedance matcher applied to a PVD (Physical Vapor Deposition) pre-cleaning process. The adjustable impedance matcher comprises a cavity shell, a coil inductor, a capacitor assembly and a radio frequency source connecting port, a coil inductor is installed on the inner side wall of the cavity shell, and a capacitor assembly is installed at the bottom in the cavity shell. The capacitor assembly comprises two capacitor installation bases distributed in the front-back direction, the chip capacitor C is installed on a chip capacitor installation base, and the front end and the rear end of the chip capacitor installation base are installed on the two chip capacitor installation bases respectively. According to the utility model, by adopting the matching network with a fixed structure, the design is more concise, the cost is lower, the adaptability is stronger, different capacitors are adopted for matching according to the frequency change, the operation is simple, the controllability is strong, and the troubleshooting is convenient.

Description

TECHNICAL FIELD

[0001] The utility model relates to the related technical field of radio frequency matching ware especially relates to a kind of adjustable impedance matching ware applied to PVD pre-cleaning process. BACKGROUND

[0002] Physical Vapor Deposition ((Physical Vapor Deposition, PVD) system is widely used in semiconductor manufacturing industry, both can be used for wafer factory front-end application, also can be used for equipment packaging plant back-end application. Etching (etch) and wet cleaning (wet clean) often leave a little residue at the bottom of via, copper at the bottom of via is exposed to air and can be oxidized, the existence of oxide can lead to the increase of resistivity and the decrease of binding force, so in PVD process, there is often a pre-cleaning (pre-clean) manufacturing process. Therefore, inductively coupled plasma (ICP) pre-cleaning module with stable plasma is developed, which can effectively remove organic residues and natural oxides on the surface of metal. The electrode of ICP is separated from the chamber, and the pollution is less, and ideal plasma density can be obtained under low pressure. Inductively coupled plasma system (ICPS) not only can produce high concentration plasma, make ion etching and deposition speed faster, but also can carry out reaction in low pressure environment, ensure good anisotropy and good selectivity of plasma. Relevant experiments show that the input power of the system directly affects the concentration and pressure of the plasma. In order to maximize the transmission of input power, the load impedance should be equal to the internal resistance of the radio frequency source, so it is necessary to design the corresponding matching structure in the process of using ICP technology.

[0003] In the actual working process of ICP, the working frequency of the radio frequency power source supporting the inductively coupled plasma system (ICPS) is not a single fixed value, but works within a certain frequency range, the center frequency is the theoretical working frequency and has a certain bandwidth, and the actual working frequency is within the overall bandwidth. Due to the change of working frequency, the corresponding reactance value of the capacitor and inductor constituting the matching network must change with the frequency, so that the corresponding impedance of the matching network will change, which causes the equivalent impedance and the internal resistance of the radio frequency source to be not equal, so that the matching purpose cannot be achieved, and the maximum transmission power cannot be achieved.

[0004] From the analysis, it can be seen that the working frequency of the system is not fixed, and the smaller the center frequency of the radio frequency power source is, the greater the bandwidth in the input frequency range is, and at this time, the matching state of the corresponding radio frequency power source matching ware will also change more compared with the center frequency position. In the manufacturing process of working frequency 400KHz, the influence caused by frequency change will be more obvious, so it is very important to design the corresponding adjustable matching ware for 400K working frequency.

[0005] In view of the above defects, the designer actively studies and innovates to create an adjustable impedance matching device applied to the PVD pre-cleaning process, so that it has more industrial application value. Content of the utility model

[0006] To solve any one of the above technical problems, the purpose of the utility model is to provide an adjustable impedance matching device applied to the PVD pre-cleaning process.

[0007] To achieve the above purpose, the utility model adopts the following technical scheme:

[0008] An adjustable impedance matching device applied to the PVD pre-cleaning process, comprising a chamber shell, a coil inductance, a capacitor assembly and a radio frequency source connection port.

[0009] The coil inductance is installed on the inner side wall of the chamber shell, the capacitor assembly is installed at the bottom in the chamber shell, and the radio frequency source connection port is arranged on one side of the capacitor assembly.

[0010] The capacitor assembly comprises two capacitor mounting bases distributed along the front-back direction, a patch capacitor C is installed on a patch capacitor mounting seat, and the front and rear ends of the patch capacitor mounting seat are respectively installed on the two patch capacitor mounting bases.

[0011] The radio frequency source is connected to the radio frequency source connection port, the output end of the radio frequency source is connected to the matching network, the coil inductance comprises an inductance L1 and an inductance L2, the matching network comprises the inductance L1, the inductance L2 and the patch capacitor C, the inductance L1 is connected in series with the patch capacitor C, and the inductance L2 is connected in parallel on the series connection of the inductance L1 and the patch capacitor C.

[0012] As a further improvement of the utility model, the bottom of the rear end of the patch capacitor mounting base is installed in the chamber shell through a plurality of grounding mounting bases, and the bottom of the front end of the patch capacitor mounting base is installed in the chamber shell through a plurality of insulating mounting bases.

[0013] As a further improvement of the utility model, the two patch capacitor mounting bases are connected together through a plurality of insulating mounting columns.

[0014] As a further improvement of the utility model, a plurality of patch capacitor mounting holes are uniformly distributed on the patch capacitor mounting base along the left-right direction, and the front and rear ends of the patch capacitor mounting seat are respectively connected with the patch capacitor mounting holes.

[0015] As a further improvement of the utility model, at least one patch capacitor C is installed between the two patch capacitor mounting bases along the left-right direction.

[0016] Through the above scheme, the utility model at least has the following advantages:

[0017] The utility model discloses a convenient replacement structure is designed for capacitor component, uses the patch capacitor to replace traditional copper sheet capacitor structure, and the model and type of patch capacitor produced on the market are very extensive, and the cost and time of obtaining demand capacitor value are more convenient and faster than the design of demand inductance, so that the matching device has better adjustability and higher precision.

[0018] The utility model discloses a more simple, lower cost and stronger adaptability matching network design of fixed structure, different capacitors are used for matching for frequency change, and the operation is simple, controllability is strong, and problem troubleshooting is convenient.

[0019] The above description is only a summary of the technical scheme of the utility model, in order to more clearly understand the technical means of the utility model, and can be implemented according to the content of the specification, the following is the preferred embodiment of the utility model and is described in detail with the drawings. DRAWINGS

[0020] In order to more clearly illustrate the technical scheme of the embodiment of the utility model, the following will briefly introduce the drawings needed in the embodiment, and it should be understood that the following drawings only show some embodiments of the utility model, and should not be regarded as the limitation to the scope, and for ordinary skilled person in the art, other related drawings can be obtained according to these drawings without creative labor.

[0021] Figure 1 It is the structure schematic view of the adjustable impedance matching device for PVD pre-cleaning process of the utility model,

[0022] Figure 2 It is Figure 1 structure schematic view in,

[0023] Figure 3 It is the impedance matching principle schematic view of prior art,

[0024] Figure 4 It is the impedance matching principle schematic view of the utility model,

[0025] Figure 5 It is Figure 4 Equivalent principle schematic view of,

[0026] Among them, the meaning of each figure mark in the drawing is as follows.

[0027] Chamber shell 1, coil inductance 2, capacitor component 3, radio frequency source 4, matching network 5, radio frequency source connecting port 6,

[0028] Patch capacitor mounting base 31, ground mounting base 32, insulating mounting base 33, insulating mounting column 34, patch capacitor mounting seat 35, patch capacitor mounting hole 36, patch capacitor C 37. DETAILED DESCRIPTION

[0029] The specific embodiments of the present application will be further described in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but not to limit the scope of the present application.

[0030] In order for those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0031] EMBODIMENT

[0032] As shown in the drawings, Figures 1-5

[0033] An adjustable impedance matching device applied to PVD pre-cleaning process, comprising a chamber shell 1, a coil inductance 2, a capacitor assembly 3 and a radio frequency source connection port 6.

[0034] The coil inductance 2 is installed on the inner side wall of the chamber shell 1, and the capacitor assembly is installed at the bottom in the chamber shell 1. The radio frequency source connection port 6 is arranged on one side of the capacitor assembly 3.

[0035] The capacitor assembly 3 comprises two capacitor mounting bases 31 distributed along the front-rear direction. The patch capacitor C37 is installed on the patch capacitor mounting seat 35, and the front and rear ends of the patch capacitor mounting seat 35 are respectively installed on the two patch capacitor mounting bases 31.

[0036] The bottom of the rear end of the patch capacitor mounting base 31 is installed in the chamber shell 1 through a plurality of grounding mounting bases 32, and the bottom of the front end of the patch capacitor mounting base 31 is installed in the chamber shell 1 through a plurality of insulating mounting bases 33. The two patch capacitor mounting bases 31 are connected together through a plurality of insulating mounting columns 34. A plurality of patch capacitor mounting holes 36 are uniformly distributed on the patch capacitor mounting base 31 along the left-right direction, and the front and rear ends of the patch capacitor mounting seat 35 are respectively connected with the patch capacitor mounting holes 36.

[0037] ​Furthermore, at least one patch capacitor C37 is installed between the two patch capacitor mounting bases 31 along the left-right direction.

[0038] The radio frequency source 4 is connected to the radio frequency source connection port 6, and the output end of the radio frequency source 4 is connected to the matching network 5; the coil inductor 2 includes an inductor L1 and an inductor L2; the matching network 5 includes the inductor L1, the inductor L2 and the patch capacitor C37; the inductor L1 is connected in series with the patch capacitor C37; and the inductor L2 is connected in parallel to the series connection of the inductor L1 and the patch capacitor C37.

[0039] The first embodiment of the utility model:

[0040] Referring to Figure 1 and Figure 2 , the chamber shell 1 includes a radio frequency source input end, a coil inductor 2 fixed inside the overall device structure and a capacitor assembly 3. The capacitor assembly 3 is composed of a patch capacitor mounting base 31, a ground mounting base 32, an insulating mounting base 33, an insulating mounting column 34, a patch capacitor mounting seat 35, a patch capacitor mounting hole 36 and a patch capacitor C37. A plurality of patch capacitor mounting holes 36 are reserved on the patch capacitor mounting base 31, and all are patch capacitor parallel structures, which facilitates subsequent accurate adjustment by selecting more capacitors with different capacitance values according to the on-site measurement results, so that the matching device reaches a matching state and the maximum power transmission is realized.

[0041] The working process and principle of the embodiment:

[0042] In operation, the radio frequency source 4 is connected to the input end of the chamber shell 1 to provide input power for the overall structure. The coil inductor 2 inside the matching device forms an inductively coupled plasma (ICP) pre-cleaning mode with the chamber to have stable plasma. The corresponding patch capacitor C37 is connected to the matching device capacitor connection. The impedance value after connecting the matching device is measured by using a connected network analyzer. If the measured impedance value and the load impedance are in a conjugate state, it is determined that the matching device structure is in a matching state. When it is not matched, the patch capacitor needs to be replaced and adjusted according to the measured impedance value. The patch capacitor can achieve more accurate adjustment to reach a matching state and realize maximum power transmission.

[0043] The second embodiment of the utility model:

[0044] As shown in Figure 3 , the function of the existing impedance matching mode is to obtain an equivalent impedance equal to the conjugate of the internal resistance of the radio frequency source by adjusting the matching device. The equivalent impedance includes a load impedance Z load and the impedance of the matching network. When the equivalent impedance Z in is completely equal to the internal resistance Z0 of the radio frequency source, it is called matching completion, which can avoid reflection and optimize the working efficiency of the radio frequency source, and ensure the stability of the entire system.

[0045] A structure that can assist in adjusting the operating frequency of the common 400K impedance matcher needs to be added. The pre-clean in the physical vapor deposition (PVD) system on the market only defaults to a fixed impedance value at the ideal frequency. This results in the matcher only being able to achieve a matching state at a single frequency point. During the impedance point matching process, there may be incomplete matching, which cannot maximize the transmission power and, to a certain extent, affects the subsequent use of the machine. In order to solve the problem of different operating frequency points for different models of machines, a frequency-adjustable impedance matcher structure is designed. This allows the circuit load to be fully matched even when the operating frequency of the RF source changes, maintaining the stability of the equipment.

[0046] The matching network of the present invention is as follows Figure 4 As shown, inductors and capacitors are used for impedance matching. An inductor is divided into two parallel structures. Assuming the total inductance value is L and the ratio of the two inductances is n1:n2, the equivalent inductance values ​​of the two branches are:

[0047]

[0048] The equivalent matching network diagram is as follows Figure 5 As shown, one parallel branch is formed by inductor L2, and the other parallel branch is formed by inductor L1 and chip capacitor C37 in series. By adjusting the size of chip capacitor C37, the equivalent impedance value of the branch changes. When the impedance value of chip capacitor C37 is greater than the impedance value of inductor L1, the branch is capacitive, and the impedance of the two parallel branches is equivalent to a parallel structure of capacitor and inductor. When the impedance value of chip capacitor C37 is smaller than the impedance value of inductor L1, the branch is inductive, and the impedance of the two parallel branches is equivalent to a parallel structure of inductor and inductor.

[0049] During the design process, the load impedance value is first measured using an instrument. The default value is the load impedance under ideal conditions, that is, at a frequency of 400KHz. A matching network is designed based on the impedance. When the matching network is connected in parallel with the RF source internal resistance Z0, the matching effect is achieved when the value is equal to the conjugate value of the load impedance. The impedance calculation formula for capacitors and inductors is as follows:

[0050]

[0051] X L =jωL

[0052] ω=2πf, where f is the frequency. As the frequency increases, the capacitive reactance decreases and the inductive reactance increases.

[0053] Equivalent impedance Z after loading the matching network in , calculated as:

[0054]

[0055] Substitute the impedance calculation formula of the capacitance and the inductance:

[0056]

[0057] When the working frequency of the circuit changes, the corresponding equivalent impedance changes, which can be matched by adjusting the size of the capacitance or inductance. In the actual process, the design of the inductance and the parasitic of the induced electromagnetic field generated by the inductance are more complex, and there are more uncontrollable factors. Therefore, by changing the capacitance C to adjust the impedance value, it is more easy to control and load in the actual production and installation process. The types and types of patch capacitors on the market cover a wide range, and the cost and time of obtaining the required capacitance value are more convenient and faster than the design of the required inductance. Therefore, in the overall structure design, the capacitance connection part can be designed as a structure convenient to replace, and the size of the capacitance value at different frequencies is prepared in advance through theoretical calculation, and timely processing and installation are carried out according to the on-site measurement and working conditions. The impedance matching device and the chamber are designed as an integrated structure, which greatly reduces the complexity of the design and improves the integrity of the working structure.

[0058] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Therefore, the features limited by "first", "second" and the like can be explicitly or implicitly included one or more features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0059] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected, it can be mechanically connected, or it can be electrically connected, it can be directly connected, or it can be indirectly connected through an intermediate medium, it can be the communication between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0060] The above merely is preferred implementation manner of the present application, and is not used for limiting the present application, it should be pointed out, for ordinary skilled person in the technical field, on the premise of not departing from the technical principle of the present application, can also make several improvements and variations, these improvements and variations also should be considered as the protection scope of the present application.

Claims

1. An adjustable impedance matcher for use in a PVD pre-cleaning process, comprising a chamber housing (1), a coil inductor (2), a capacitor assembly (3), and a radio frequency source connection port (6); Its characteristics are: A coil inductor (2) is installed on the inner side wall of the chamber housing (1), a capacitor component (3) is installed on the bottom of the chamber housing (1), and a radio frequency source connection port (6) is provided on one side of the capacitor component (3); The capacitor assembly (3) includes two capacitor mounting bases (31) distributed along the front-to-back direction, the chip capacitor C (37) is mounted on the chip capacitor mounting base (35), and the front and rear ends of the chip capacitor mounting base (35) are respectively mounted on the two chip capacitor mounting bases (31); A radio frequency source (4) is connected to the radio frequency source connection port (6), an output end of the radio frequency source (4) is connected to a matching network (5), the coil inductor (2) includes an inductor L1 and an inductor L2, the matching network (5) includes an inductor L1, an inductor L2 and a chip capacitor C (37), the inductor L1 and the chip capacitor C (37) are connected in series, and the inductor L2 is connected in parallel to the series-connected inductor L1 and the chip capacitor C (37).

2. The adjustable impedance matcher for PVD pre-cleaning process according to claim 1, characterized in that: The bottom of the rear end of the chip capacitor mounting base (31) is mounted in the chamber housing (1) via a plurality of grounding mounting bases (32), and the bottom of the front end of the chip capacitor mounting base (31) is mounted in the chamber housing (1) via a plurality of insulating mounting bases (33).

3. The adjustable impedance matcher for PVD pre-cleaning process according to claim 1, wherein: The two chip capacitor mounting bases (31) are connected together via a plurality of insulating mounting columns (34).

4. The adjustable impedance matcher for PVD pre-cleaning process according to claim 1, wherein: A plurality of chip capacitor mounting holes (36) are evenly distributed along the left and right directions on the chip capacitor mounting base (31), and the front and rear ends of the chip capacitor mounting seat (35) are respectively connected to the chip capacitor mounting holes (36).

5. The adjustable impedance matcher used in a PVD pre-cleaning process according to claim 1, wherein: At least one chip capacitor C (37) is installed between the two chip capacitor mounting bases (31) along the left-right direction.

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