阅读说明：本技术 上电极系统、等离子体腔室及等离子体产生方法 (Upper electrode system, plasma chamber and method of generating plasma ) 是由 刘春明 于 2018-06-07 设计创作，主要内容包括：本发明公开了一种上电极系统、等离子体腔室及等离子体产生方法。该上电极系统包括射频电源、线圈、连接在射频电源和线圈之间的匹配器,还包括在线圈和地之间并联设置的开关组件和分压电容。本发明通过开关组件切换的方式实现匹配网络的切换,结合对等离子体的起辉状态判断和对区配体的匹配状态监测,无需人工干预即可解决起辉异常问题,并且不增加起辉步骤,减小了对工艺结果的影响。(The invention discloses a kind of upper electrode system, plasma chamber and method of generating plasma.The upper electrode system includes radio-frequency power supply, coil, the adaptation being connected between radio-frequency power supply and coil, further includes the switch block and derided capacitors being arranged in parallel between coil and ground.The present invention realizes the switching of matching network in such a way that switch block switches, it is monitored in conjunction with the build-up of luminance state judgement of plasma and to the matching status of area's ligand, build-up of luminance abnormal problem can be solved without manual intervention, and do not increase build-up of luminance step, reduce the influence to process results.)

1. a kind of upper electrode system, including radio-frequency power supply, coil, the matching being connected between the radio-frequency power supply and the coil Device, which is characterized in that further include: the switch block and derided capacitors being arranged in parallel between the coil and ground.

2. upper electrode system according to claim 1, which is characterized in that the switch block is relay.

3. upper electrode system according to claim 2, which is characterized in that the relay is high pressure resistant vacuum radio frequency relay Device.

4. upper electrode system according to claim 3, which is characterized in that when the high pressure resistant vacuum radio frequency relay disconnects Electrode between junction capacity be less than 0.1pF.

5. upper electrode system according to claim 1-4, which is characterized in that the adaptation is capacitive element And/or L-type network, the T-type network, one of pin network of inductive element composition.

6. upper electrode system according to claim 5, which is characterized in that the capacitive element of the adaptation is adjustable electric Hold, inductive element is controllable impedance.

7. upper electrode system according to claim 1, which is characterized in that the derided capacitors are for fixed capacity or with solid Determine the variable capacitance that mode uses.

8. a kind of plasma chamber characterized by comprising

Upper electrode system as described in one in claim 1-7, the observation window being arranged on chamber outer wall and setting exist Spectrometer on the outside of the observation window.

9. a kind of method of generating plasma generates plasma using plasma chamber as claimed in claim 8, special Sign is, comprising:

1) switch block is disconnected, the radio-frequency power supply load radio-frequency power is opened；

2) judge whether the input impedance of the adaptation matches with the output impedance of the radio-frequency power supply, such as otherwise alarm and whole 3) only technique then enters step in this way；

3) judge plasma in the plasma cavity whether build-up of luminance, then continue technique in this way, such as otherwise enter step 4)；

4) radio-frequency power supply is closed, the switch block is set as being closed；

5) radio-frequency power supply is opened, radio-frequency power is loaded；

6) judge whether the input impedance of the adaptation matches with the output impedance of the radio-frequency power supply, such as otherwise alarm and whole 7) only technique then enters step in this way；

7) switch block is disconnected, technique is continued.

10. method of generating plasma according to claim 9, which is characterized in that judge in the plasma cavity Plasma whether build-up of luminance, specifically include:

The spectrum of the generation of the plasma in the plasma cavity is acquired, through the observation window using the spectrometer to sentence Disconnected plasma whether build-up of luminance.

Technical field

The present invention relates to semiconductor manufacturing equipments, and in particular to upper electrode system, plasma chamber and plasma Body production method.

Background technique

Plasma is widely used in the production process of semiconductor devices.In plasma etching or depositing system In, radio-frequency power supply is powered to plasma chamber to generate plasma.Contain a large amount of electronics, ion, excitation in plasma Atom, molecule and the free radical isoreactivity particle of state, these active particles and are placed in cavity and expose to the open air under plasma environment Wafer interaction, make wafer material surface that various physical and chemical reactions occur, so that material surface property be made to become Change, completes the etching or other technical process of wafer.

With the development of super large-scale integration, since plasma process is to the especially tight of the damage problem of device Weight, may influence the performance and reliability of device, also cause the permanent mistake of device, reduce yield rate.Usually because etc. The radiation of ion generation, the caused damage of electronics acceleration effect, can be resolved by reducing power.But it is risen in low-power False build-up of luminance state is frequently present of when brightness, i.e. adaptation only matches chamber and other stray capacitances, and no plasma produces It is raw.The phenomenon is in plasma enhanced chemical vapor deposition method (Plasma Enhanced Chemical Vapor Deposition, PECVD), chips in etching (IC ETCH) and physical vapour deposition (PVD) (Physical Vapor Deposition, PVD) in occur.Optical emission spectra (Optical Emission can usually be passed through Spectroscopy, OES), it is made to determine whether build-up of luminance, however not can solve the problem of build-up of luminance exception, it usually needs is artificial Intervention is walked as build-up of luminance by the build-ups of luminance such as hyperbar means, then is transitioned into normal process process.But the change based on the free radical It learns in etching process, especially etching precision, pattern control in demanding technique, when the process conditions and technique of build-up of luminance step It is long to have tremendous influence to etching result, increase debugging difficulty, while reducing board production capacity.

Summary of the invention

In order to solve the above problem in the prior art, the present invention propose a kind of upper electrode system, plasma chamber and Method of generating plasma.

According to the first aspect of the invention, propose a kind of upper electrode system, including radio-frequency power supply, coil, be connected to it is described Adaptation between radio-frequency power supply and the coil, further includes: the switch block that is arranged in parallel between the coil and ground and Derided capacitors.

Preferably, the switch block is relay.

Preferably, the relay is high pressure resistant vacuum radio frequency relay.

Preferably, junction capacity is less than 0.1pF between electrode when the high pressure resistant vacuum radio frequency relay disconnects.

Preferably, the adaptation is L-type network, the T-type network, pin network that capacitive element and/or inductive element form One of.

Preferably, the capacitive element of the adaptation is tunable capacitor, and inductive element is controllable impedance.

Preferably, the derided capacitors are fixed capacity or the variable capacitance used in a position-stable manner.

According to the second aspect of the invention, propose a kind of plasma chamber, including above-mentioned upper electrode system, setting in chamber Observation window on chamber outer wall and the spectrometer being arranged on the outside of the observation window.

According to the third aspect of the invention we, it proposes a kind of method of generating plasma, is produced using above-mentioned plasma chamber Raw plasma, comprising:

1) switch block is disconnected, the radio-frequency power supply load radio-frequency power is opened；

2) judge whether the input impedance of the adaptation matches with the output impedance of the radio-frequency power supply, such as otherwise alarm And technique is terminated, it then enters step in this way 3)；

3) judge plasma in the plasma cavity whether build-up of luminance, then continue technique in this way, such as otherwise enter step It is rapid 4)；

4) radio-frequency power supply is closed, the switch block is set as being closed；

5) radio-frequency power supply is opened, radio-frequency power is loaded；

6) judge whether the input impedance of the adaptation matches with the output impedance of the radio-frequency power supply, such as otherwise alarm And technique is terminated, it then enters step in this way 7)；

7) switch block is disconnected, technique is continued.

Preferably, the plasma in the plasma cavity is acquired through the observation window using the spectrometer to generate Spectrum, with judge plasma whether build-up of luminance.

The present invention between coil and ground by being arranged in parallel switch block and derided capacitors, when under capacitive coupling mode When appearance matches the not false matching status of build-up of luminance, realizes that coil is directly grounded by switching switch block, provided for coil raised Brightness voltage, to guarantee the build-up of luminance ability of plasma system.And in conjunction with the judgement of the build-up of luminance state of plasma and to area The monitoring of the matching status of ligand can be solved build-up of luminance abnormal problem without manual intervention, and not increase build-up of luminance step, reduce Influence to process results.

Detailed description of the invention

Exemplary embodiment of the invention is described in more detail in conjunction with the accompanying drawings, it is of the invention above-mentioned and its Its purpose, feature and advantage will be apparent, wherein in exemplary embodiment of the invention, identical reference label Typically represent same parts.

Fig. 1 shows the schematic diagram of upper electrode system in accordance with an exemplary embodiment of the invention；

Fig. 2 shows the schematic diagrames of the plasma chamber comprising upper electrode system shown in FIG. 1；

Fig. 3 shows the flow chart that the method for plasma is generated using plasma chamber shown in Fig. 2.

Specific embodiment

The preferred embodiment that the present invention will be described in more detail below with reference to accompanying drawings.Although showing the present invention in attached drawing Preferred embodiment, however, it is to be appreciated that can realize the present invention without should be by embodiments set forth herein in a variety of manners It is limited.On the contrary, thesing embodiments are provided so that the present invention is more thorough and complete, and can be by model of the invention It encloses and is completely communicated to those skilled in the art.

Fig. 1 shows the schematic diagram of upper electrode system in accordance with an exemplary embodiment of the invention.As shown in Figure 1, on this Electrode system includes radio-frequency power supply 11, adaptation 12, coil 13, and is arranged in parallel switch block between coil 13 and ground 124 and derided capacitors 123.When switch block 124 disconnects, coil 13 is grounded by derided capacitors 123；When switch block 124 When closure, coil 13 is directly grounded.In normal state, switch block 124 disconnects.

In the plasma chamber of the upper electrode system of application in accordance with an exemplary embodiment of the invention, polar system is powered on Can simplify between coil 13 in system and the medium window in plasma chamber and lower electrode for three capacitors it is concatenated equivalent Circuit model: the air capacitor C between coil 13 and medium window_a, medium window itself equivalent capacity C_d, medium window and lower electrode it Between equivalent capacity C_b.After being determined with upper-part mechanical dimension, the equivalent capacity of each self-forming is determined；It is applied when on coil 13 Making alive U₀When medium window under the voltage drop U that obtains_d=(X_Ca+X_Cd)*U₀/(X_Ca+X_Cd+X_Cb).Therefore, it is determined in mechanical structure In the case where, the build-up of luminance ability of the voltage decision systems on coil 13.

When coil 13 is grounded by derided capacitors 123, derided capacitors 123 are the partial pressure of coil 123, under some process conditions The capacitive coupling of coil 13 and medium window lower chamber is insufficient, cause gas to be difficult to puncture, build-up of luminance it is difficult, adaptation is by coil 13 And other distribution parameters form false matching as load.When coil 13 is directly grounded, it is equivalent to capacitor infinity, at this time line Maximum voltage can be obtained on circle 13, guarantees the build-up of luminance ability of plasma system, therefore this mode is not in that can not match The false matching status of brightness.

Inductively coupled plasma body build-up of luminance process is broadly divided into three parts: one, when gas does not puncture, load impedance is big, High voltage, low current are formed on coil 13；Two, it is coupled power by the equivalent capacity between coil 13 and medium window into true Gas breakdown is discharged by high pressure, is now in capacitive coupling mode by plenum chamber；Three, as plasma density increases, line Voltage drop is low on circle, electric current increases, into inductive coupled mode.Build-up of luminance is occurred mainly in extremely under capacitive coupling mode.

The present invention is arranged in parallel switch block 124 and derided capacitors 123 between coil 13 and ground, passes through switch block 124 switching, realize to coil 13 by derided capacitors 123 carry out partial pressure and coil 13 be directly grounded between switching.When When occurring matching the not false matching status of build-up of luminance under capacitive coupling mode, realize that coil 13 is direct by switching switch block 124 Ground connection provides high starting voltage for coil 13, to guarantee the build-up of luminance ability of plasma system.

In one example, switch block 124 is relay, to realize that coil 13 is connect and direct with derided capacitors 123 Automatic switchover between ground connection.

The preferably high pressure resistant vacuum radio frequency relay of the relay, contact resistance is small and stablizes, and is suitable for radio frequency occasion. High-impedance state is formed to the frequency of the radio-frequency power supply when relay disconnects.For example, for the radio-frequency power supply 11 of 13.56MHz, It is required that junction capacity < 0.1pF between relay electrode when disconnecting, forms 117K ohm of high-impedance state to the frequency of 13.56MHz at this time, Guarantee ground branch is off state.Upper electrode system according to the present invention can also be used for 2MHz, 27.12MHz and higher frequency, It needs to be used in combination frequency and type selecting is carried out to relay.

In one example, adaptation 12 is L-type network, the T-type network, π type that capacitive element and/or inductive element form One of network realizes the conjugate impedance match between singal source resistance and load impedance, makes to load to adjust backend load impedance Obtain peak power output.

Capacitive element in adaptation 12 is preferably tunable capacitor, and inductive element is preferably controllable impedance, in order to realize The adjusting of backend load impedance.

Such as it is shown in FIG. 1 power on a grade system, wherein adaptation 12 be made of tunable capacitor 121 and tunable capacitor 122 L-type network.

In one example, derided capacitors 123 are fixed capacity or the variable capacitance used in a position-stable manner.Partial pressure electricity Hold 123 to be mainly used for dividing for coil 13, and adjustable matching range.It is capacitor that 123 value of derided capacitors, which generally follows principle, Capacitive reactance be approximately equal to the half of coil induction reactance, i.e.,To distribute voltage appropriate on coil 13, but can be according to reality Border use demand is adjusted.

Based on the same inventive concept, the invention also provides a kind of plasma chambers, as shown in Figure 2 comprising above-mentioned Electrode system 10, the observation window 16 being arranged on chamber outer wall and the spectrometer 17 being arranged on the outside of observation window.The plasma Fluid chamber further comprises vacuum cavity 18, lower electrode 15, medium window 19.

When passing through radio-frequency power supply 11 and the load radio-frequency power of adaptation 12 on the coil 13 in chamber, by vacuum chamber 18 In the excitation of hypobaric reaction gas be plasma 14, and plasma 14 can occur glow discharge and generate spectrum, through peace Observation window 16 on 18 outer wall of vacuum chamber enters spectrometer 17.Machine is controlled by the way that spectrometer 17 is connected to PC, and is borrowed It helps corresponding control algolithm to handle related data in real time, can be realized the monitoring of plasma, complete the standard to build-up of luminance state Really grasp.

Based on the same inventive concept, the invention proposes a kind of method of generating plasma, utilize with plasma Chamber generates plasma.As shown in figure 3, method includes the following steps:

Step 1: disconnecting switch block, open radio-frequency power supply and load radio-frequency power.

System initialization is usually carried out first, upon initialization, switch block 124 of having no progeny, such as relay, it beats later It opens radio-frequency power supply 11 and loads radio-frequency power.

In the case where switch block 124 disconnects, the logical end access derided capacitors 123 of coil 13 are divided.

Step 2: judging whether the input impedance of adaptation matches with the output impedance of radio-frequency power supply, such as otherwise alarm and whole Only technique then enters step 3 in this way.

When the load impedance (cascaded structure of coil 13 and capacitor 123) of 12 rear end of adaptation passes through the transformation of adaptation 12 Afterwards, with the output impedance conjugate impedance match of radio-frequency power supply 11, then the output power of radio-frequency power supply 11 is all applied to plasma chamber Room, otherwise will lead on radio-frequency transmission line that there are biggish reflection powers.

Step 3: judge plasma in plasma cavity whether build-up of luminance, then continue technique in this way, such as otherwise enter step Rapid 4.

Since the end access capacitor 123 of coil 13 is divided, easy capacitive coupling is insufficient under certain processing conditions, from And cause build-up of luminance difficult, it is therefore desirable to which whether build-up of luminance is judged plasma.

In one example, the plasma 14 in plasma cavity is acquired through observation window 16 using spectrometer 17 to generate Spectrum, with judge plasma whether build-up of luminance.

Step 4: closing radio-frequency power supply, switch block is set as being closed.

In the case where plasma 14 does not have build-up of luminance, radio-frequency power supply, closure switch component 124 are closed.

Step 5: opening radio-frequency power supply, load radio-frequency power.

In the case where closure switch component 124, the end of coil 13 is directly grounded, and is equivalent to capacitor infinity, at this time Maximum voltage can be obtained on coil 13, guarantee the build-up of luminance ability of plasma.

Step 6: judging whether the input impedance of adaptation matches with the output impedance of radio-frequency power supply, such as otherwise alarm and whole Only technique then enters step 7 in this way.

Step 7: disconnecting switch block, continue technique.

In the case where ensure that 14 normal build-up of luminance of plasma, derided capacitors are accessed in the end of hold-in winding 13 Continue technique in the case where 123, avoiding 13 ground state time of coil length causes medium window 19 to be etched, between upper and lower radio frequency The problem of coupling influence etch topography.

The embodiment of the present invention is described above, above description is exemplary, and non-exclusive, and also not Example is respectively applied disclosed by being limited to.Without departing from the scope and spirit of embodiment described, for the art Those of ordinary skill for many modifications and changes are obvious.The selection of term used herein, it is intended to best The principle and practical application of embodiment is explained on ground, or so that other those of ordinary skill of the art is understood and disclosed herein Embodiment.