JP2002503031A - Plasma-assisted processing chamber for individually controlling seed density - Google Patents

Abstract

(57) SUMMARY The present invention provides a plasma assisted processing apparatus and method for a workpiece that separately controls a seed density in a processing plasma. The present invention has a processing chamber (102) and at least one auxiliary chamber (104). The auxiliary chamber is capable of generating an auxiliary plasma and transferring it to the processing chamber. To control the density of the particle species in the processing chamber, the present invention provides a filter (108) interposed between the auxiliary chamber and the processing chamber, a power supply for the main chamber, and a number of separate inputs to the processing chamber. Such auxiliary chambers, or a combination thereof. The auxiliary plasma may be filtered, combined with the plasma generated in the main chamber, combined with another auxiliary plasma, or a combination thereof to separate the density of the species of the processing plasma. May be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

(Cross Reference) The present invention was filed on February 9, 1998, and described in "Plasma Assisted Processing Chamber (Plasma Assisted) for Individually Controlling Charged Particle Density and Neutral Density.
Processing Chamber with Separate Co
control of Charged Particle Density an
d Neutral Density " United States Patent No. No. 09 / 020,960, which is a continuation-in-part application of US patent application Ser.

[0002] The present invention relates to a plasma reactor used to etch and / or deposit a film on a workpiece, and more particularly to independently controlling certain densities within a main processing chamber of the reactor. For a possible reactor.

[0003]

[Prior art]

While manufacturing microelectronic devices on a workpiece, a plasma reactor may be used to perform various processes on the workpiece, such as a semiconductor wafer. The wafer is placed in a vacuum chamber of the reactor and a processing gas is introduced. The process gas is irradiated with electromagnetic energy to ignite and maintain the plasma. Depending on the composition of the gas from which the plasma is formed, the plasma may be used to etch certain materials from the workpiece, or may be used to deposit a thin layer of material on the workpiece. Good.

[0004] Examples of typical process gases used as etchants when plasma reactors are used for etching include, among others, Cl ₂ , BCl ₃ , CF ₄ , SF ₆ , NF ₃ , HBr and various C _x. including H _y F _z gas. However, these gases do not undergo a chemical reaction under these conditions to sufficiently etch the material to be removed from the workpiece being processed in the reactor. Here the plasma is active.

[0005] A process gas is irradiated with electromagnetic energy to ignite and maintain the plasma. Neutral and charged particles, as well as other particles and material species, are generated from the process gas into the plasma. For example, if Cl ₂ is used as the process gas, the following species of neutral and charged particles may be present in the chamber.

[0006]

(Equation 1)

[0007] Neutral particles formed from etchant gases, such as Cl, F and Br, are extremely unstable and susceptible to reacting and chemically reacting with the material on the workpiece to generate gaseous substances. , Which can be effectively used to effectively remove or etch material from a workpiece. For example, if it is desired to etch silicon from the surface of a semiconductor wafer, Cl ₂ is symmetrically dissociated to form Cl neutrals in the plasma. These Cl neutral particles react with the silicon of the wafer according to the following equation.

[0008]

(Equation 2)

[0009] The product SiCl _x is the gas that is ultimately exhausted from the processing chamber.

[0010] However, the above-described reaction may not occur unless sufficient energy is applied. This energy can be in the form of heat, but in plasma-assisted etching processes, much of this energy is typically from physical impact on the wafer surface. This physical impact is the work performed by charged particles formed in the plasma from the process gas. Typically, the charged particles are attracted in the direction of the wafer by the bias power applied to the wafer support, increasing the impact and having the desired directivity to the wafer, typically perpendicular to the top surface of the wafer. . These charged particles not only supply energy to the chemical etching process associated with the neutral particles of the etchant gas, but also physically remove material from the wafer surface by impacting the particles on the wafer.

The charged particles need not be formed only from the etchant gas. Regardless of whether or not it chemically reacts with the material to be etched, any charged particle can be used as long as it can impact the wafer and achieve the desired effect.
For example, if a particular etching process requires more charged particles than can be obtained from the etchant gas alone, a non-reactive gas such as argon may be introduced. Argon forms charged particles in the plasma. The introduced argon is
It does not chemically react with the wafer material, but increases the overall availability of charged particles used to bombard the wafer to a desirable state.

[0012] The concentration or density in the plasma of both neutral particles formed from the etchant gas and charged particles formed from all of the process gases may be characteristic during the etching process, and even the properties exhibited by the etched workpiece. Plays a very important role in making decisions. For example, both act to etch material from a workpiece. Thus, increasing all densities has the effect of increasing the overall etch rate, which is a desirable effect in most cases.

However, it must also be mentioned that the physical impact of the charged particles on the workpiece may result in etching of the material that one does not want to remove. Thus, increasing the density of charged particles may increase the etch rate of the material to be etched, but may also damage devices formed on the workpiece. As a result, it is more preferable to increase only the density of neutral particles of the etchant gas by the plasma to increase the overall etching rate.

Also, the relative densities of neutral and charged particle species of the etching gas formed by the plasma can be significantly affected by etching process characteristics such as, for example, etch selectivity, etch feature profile, and microloading of etch rates. Bring effect.

Here, the term etch selectivity refers to the ratio of the etch rates of two different materials on a workpiece being etched in a plasma reactor. In order to form features and patterns in the various layers of the workpiece, there must be a selectivity that separates the material to be etched from the material to be etched.
In a typical flow, the silicon layer on the workpiece is etched much faster than the photoresist or oxygen-containing layer on the workpiece, and the pattern is etched into the silicon. These are referred to as high silicon to photoresist selectivity and high silicon to oxide selectivity, respectively.

The following example of etching a hole from a silicon layer on a semiconductor wafer to an underlying gate oxide layer is an example showing the importance of a high selectivity. Prior to performing the etching, a layer of photoresist material is formed on the surface of the silicon layer on the unetched areas. Therefore, no photoresist is formed in the region where the hole is etched. The desired result obtained in the etching process is that the silicon layer intended to form the hole is etched quickly but does not significantly etch the surrounding photoresist or underlying gate oxide layer. Therefore, it is desired that the etching selectivity of silicon to photoresist and silicon to oxide be high. If a moderate level of selectivity is not maintained, so-called "punch-through"
Conditions can arise that can etch the photoresist and oxide layers and damage devices formed on the workpiece.

The density of the plasma species has a significant effect on the selectivity exhibited during the etching process. For example, if the process chemistry reacts chemically with a material (eg, silicon) in which the neutral particles of the etchant gas are etched more than other materials (eg, photoresist and oxide), neutral species By increasing the density of the material, it becomes easier to achieve a desired selectivity by increasing the etching rate of the material to be etched as compared with other materials. Conversely, charged particles tend to etch all of the various materials of the workpiece, as they utilize physical impact to remove material from the workpiece surface. Therefore, increasing the density of charged particle species in the plasma will increase the overall etch rate of the workpiece material.

Therefore, when the neutral species of the etchant gas is increased under certain conditions, the selectivity increases, and when the neutral species is decreased, the selectivity decreases. On the other hand, increasing the density of charged particle species under certain conditions lowers the selectivity, and decreasing the charged particles under certain conditions increases the selectivity. Thus, one method of optimizing the desired selectivity of the etching process is to use an amount of charged particles sufficient to facilitate the reaction between the material to be etched and the neutral particles of the etchant gas, rather than the material to be etched. Is to increase the ratio between the neutral particle species and the charged particle species of the etchant gas in the plasma.

The etching feature profile shown on an etched workpiece often depends on the relative densities of the neutral and charged particle species of the etchant gas in the plasma. Here, the term etched feature profile refers to the sidewall angle of a feature etched into a layer of material on a workpiece relative to a surface plane of the workpiece. This angle can range from an over-undercut condition in which the sidewall is at an acute angle to the surface plane of the workpiece to a significantly outwardly tapered sidewall having an obtuse angle to the surface plane. In general, an upright profile where the feature sidewalls have a 90 degree angle to the surface plane of the workpiece is desired.

The undercut profile is such that neutral particles of an etching gas that chemically react with the material whose features are being etched penetrate into the material beneath the overlying photoresist layer and form an underlayer (eg, as described above). (E.g., a gate oxide layer in a silicon etching process). The higher the neutral species density of the etchant gas, the greater the degree of undercut. A passivation material is often deposited on the material to be etched to reduce the possibility of undercuts due to neutral particles of the etchant gas. Basically, the passivation material, usually formed by a plasma, deposits on the surface of the workpiece,
This has the effect of making etching difficult by neutral particles of the etchant gas. For example, in the above-described flow of silicon etching, oxygen or nitrogen is often introduced as a part of the processing gas. Oxygen or nitrogen reacts (or is introduced into the plasma by other means) with silicon etched from the semiconductor wafer to form various silicon-oxygen-containing materials and silicon-nitrogen-containing materials. These materials accumulate to varying degrees on the wafer surface and interfere with the etching effect of neutral particles of the etchant gas. Due to the effects of charged chemical species that bombard normal chemistry, the passivation material tends to be more easily formed by the sidewalls of features formed in the etched material than by the bottom of the features. This will reduce the etch rate of the feature sidewalls and also reduce the tendency for undercut profiles to form. However, if the neutral density of the etchant is high, this passivation process may not be sufficient to prevent undercut etching profiles.

The charged particle species has a very different effect on the feature profile of the etch. When the density of the charged particle species in the plasma increases, the above-described profile tapered outward may be formed. This occurs when charged particles impacting the bottom of the etched feature remove material that may subsequently redeposit on the feature sidewalls. In this way, a tapered profile results.

Thus, one way to create the desired etch profile angle is to balance the relative densities of the neutral and charged particle species of the etchant gas in the plasma. In other words, the concentrations of the neutral particle species and the charged particle species of the etchant gas are set so that a desired etching profile is formed on the assumption that each has an adverse effect on the profile.

The relative density of neutral particle species and charged particle species of the etching gas in the plasma is
It also affects the microloading of the etch rate exhibited by the etched workpiece. Here, microloading of the etch rate refers to the phenomenon that the etch rate tends to be different in areas of densely spaced etch features that are narrower than in areas of widely spaced etch features on the workpiece. When this occurs, the depth of the etched features formed in the layer of material being etched will be non-uniform, which will have undesirable consequences. Microloading of etch rates is a complex phenomenon. However, by changing the ratio between the neutral particle species and the charged particle species of the etchant gas in the plasma, the adverse effect of the microloading of the etching rate can be changed.

Therefore, by using the method of changing the density of the neutral particle species and the charged particle species in the etchant gas in the plasma, there is obtained an advantage that the microloading effect of the etching rate can be reduced.

As can be inferred from the background of the invention described above, a very desirable state can be obtained if the density of the neutral particle species and the charged particle species in the etchant gas existing in the plasma can be controlled. Obtaining a specific neutral to charged particle ratio allows optimization of processing characteristics such as, for example, etch rate, selectivity, etch feature profile and microloading of etch rate. Further, depending on the specific charged particle species ratio and neutral species ratio, the above-described processing characteristics and other characteristics may be enhanced.

However, to date, among all limitations, both the dissociation rate (ie, the rate at which neutral particles are collected in the plasma) and the ionization rate (ie, the rate at which charged particles are collected in the plasma) are both processing chambers. Because of the dependence on the power level coupled into the plasma, the coupling of the relative densities of the particle species formed in the plasma could not be changed. The density of neutral particles of the etchant gas is increased by increasing the power input in the reactor. Unfortunately, increasing the power input also increases the density of charged particles in the plasma. Similarly,
Different neutral particle densities or different ionized particle densities are relevant. As mentioned above, many of the advantages of etching properties are that the specificity between the density of neutral and charged particle species in the etchant gas, including the ratio between different neutral particle species and the ratio between different charged particle species, Is affected by changing the ratio of This is often not achieved with current plasma reactors and etching processes when increasing the density of one species often reduces the density of another.

In current reactors, the density of charged and neutral particle species may be controlled by adjusting reactor parameters such as power supply, chamber pressure and temperature. However, adjusting these parameters affects the plasma density and plasma ion energy. Thus, plasma density and plasma ion energy are related to seed density. In a reactor that uses only a capacitive power supply to generate and maintain a plasma, three properties are correlated: plasma density, ion energy, and species density. For example, if the power supply power is increased to increase the plasma density, the ion energy and the charge-to-neutral density ratio increase accordingly. Thus, adjusting the power supply or pressure to change one of several characteristics will also affect the other two.

If another reactor, such as an inductively coupled plasma reactor, that uses two power supplies to control the characteristics of the plasma is used, the plasma characteristics can be controlled well. Using a second power supply, such as an inductively coupled power supply, with a capacitive power supply can decouple the relationship between plasma density and plasma ion energy. That is, the plasma density and the plasma ion energy can be controlled separately. However, in these reactors, seed density is still related to plasma density and ion energy.

Furthermore, neither type of reactor can control the density of certain species of charged or neutral particles in the plasma, such as the ratio of Cl ⁺ to Cl ₂ ⁺ . Controlling the density of specific species of charged or neutral particles allows for much better control of the etching or deposition results and increases the processing accuracy of the workpiece.

Thus, by separately controlling the density of the plasma species, the ratio of these densities can be manipulated and a plasma reactor that optimizes process characteristics such as etch rate, selectivity, etch feature profile, etch rate microloading, etc. There is a strong need for a design and etching process.

[0031]

[Means for Solving the Problems]

The present invention provides an apparatus and method for plasma assisting a workpiece in a plasma reactor. The present invention is for separately controlling the main density of the processing plasma.

In a preferred embodiment of the present invention, the plasma reactor of the present invention has a main processing chamber and at least one auxiliary source chamber. The auxiliary source chamber generates an auxiliary plasma and is coupled to the main chamber. The auxiliary plasma is transported through a connection with a main processing chamber for processing the workpiece.
The density of neutral and charged particle species in the main processing chamber plasma may be controlled in several ways.

A filter may be used to filter the auxiliary plasma. The filter is interposed between the auxiliary source chamber and the main processing chamber. The filter can selectively filter charged particles from the auxiliary plasma. The filter may filter some or all of the charged particles. Also, the filter may filter the charged particles by their mass or velocity. The filtered auxiliary plasma is then transported to the main processing chamber to provide a desired main processing plasma density.

The main processing chamber may be capable of generating a main plasma. The incident auxiliary plasma is mixed with the main plasma generated by the main chamber to form a main process plasma. The seed density in the main processing plasma is
The auxiliary source plasma and the main chamber may be adjusted by adjusting the density of the generated plasma. A filter may be used to selectively filter charged particles from the auxiliary plasma before entering the main processing chamber.

The present invention may have several auxiliary source chambers and supply separate plasmas to the main processing chamber. Here, the density of the auxiliary source plasma is adjusted and filtered such that the combined plasma provides the desired seed density in the main processing chamber.

The species density within the main processing chamber may also be adjusted by feeding and combining other neutral radical species, such as thermally dissociated species, with the auxiliary source chamber plasma.

The present invention may utilize any known reactor layout or method that utilizes a plasma to process a workpiece to generate a desired plasma.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION

In the following description of the preferred embodiments of the present invention, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in practicing the invention. . However, it should be understood that other embodiments are available and that structural changes may be made without departing from the scope of the invention.

The Workpiece Processing Method According to the Present Invention (FIG. 1) The present invention provides a method for separately controlling the density of particle species in a plasma. The present invention separately controls the neutral and charged particle species of the etchant gas, that is, the control of the density of neutral to charged particle species, neutral to neutral and charged particle to charged particle species. Provide a way to do it. The method of the present invention provides for the primary processing chamber 102
To generate an auxiliary plasma source. The auxiliary plasma is transported to a main processing chamber or main chamber 102 containing a workpiece (not shown).

The method of the present invention uses an auxiliary source chamber 104. Auxiliary supply chamber 1
04 has at least one radiant energy applicator or auxiliary power applicator 112 for igniting the process gas to form an auxiliary plasma. The auxiliary power applicator 112 includes a microwave discharge, an inductive discharge, a capacitance discharge,
A type using an electron beam, ultraviolet light, or the like may be used. As described below, it is presently preferred that auxiliary power supply 112 utilize a helicon wave source, such as a magnetically enhanced inductively coupled power supply of auxiliary power supply 112. However, in principle, any known chamber structure used for the main processing chamber of the plasma reactor may be used to form the auxiliary source chamber 112.

The main chamber 102 used for processing the workpiece is coupled to the auxiliary source chamber 104 so that plasma particles generated in the auxiliary source chamber 104 can flow into the main processing chamber 102. The main processing chamber 102 is shown in FIG.
May have first and second main chamber power supplies not shown in FIG. As described further below, it is presently preferred to use a plasma reactor having an inductively coupled plasma power supply and a capacitive bias power supply as the first and second main chamber power supplies. However, any configuration of the workpiece processing chamber may be used as the main processing chamber 102. For example, microwaves, ultraviolet rays, electron beams, or the like may be used as a power source for the processing chamber.

A filter 108 may be inserted between the auxiliary chamber 104 and the main processing chamber 102. Conduit filter 108 operates to filter charged particle species entering main processing chamber 102. Filter 108 may be selected to selectively filter various species. Also, the filter 108 may be selected to block charged particles entering the main processing chamber 102 from being completely or selectively blocked. Further, the filter 108 may be selected to filter charged particle species in terms of mass and / or velocity.

The filter 108 may be formed in various ways depending on the density of the desired plasma species. For example, the filters are recombination type, electrostatic type, R
F-types, magnetic-field types, combinations of these types, or other types of filtering methods or devices may be used. The types of filters are described in more detail below. The choice of filter 108 depends on the type of processing gas used in the auxiliary and main chambers 104 and 102, the type of species generated or introduced in each chamber, and for processing workpieces in the main processing chamber 102. Depends on the desired density of the species used.

As described further below, the auxiliary or neutral particle source chamber 104 may generate both neutral and charged particle species, while the filter 108
Only neutral particle species may be selected to be supplied to main chamber 102. In particular, although this is preferred in some embodiments of the present invention, a major amount of neutral species, a certain amount of neutral species and a certain amount of charged species, a major amount of charged species, a selected amount of By selecting the appropriate auxiliary source chamber 104 and filter 108 parameters, the gender, or selected amount of neutral species, is provided to the main processing chamber 102. The density of sex species and charged species may be controlled.

A filtered auxiliary source plasma is supplied to the main chamber 102, which may be used to process a workpiece in this chamber, or may be combined with other processing gases to provide a desired seed density. May be generated. The filter 108 may be used as an alternative to supplying power to the main processing chamber 102 or as an alternative to control the processing plasma species density within the main processing chamber 102.

Further, the independent control of the neutral particle species and the charged particle species according to the present invention is performed by supplying different species to the processing chamber 102 as shown by reference numerals 502 and 504 in FIG. This may be achieved by using two or more auxiliary chambers 104 to form a plasma.

For example, referring to FIG. 9, one source chamber 502 generates a major amount of charged particle species, and another source chamber 504 generates a major amount of neutral particle species. You may. It is important to note that in this embodiment of the invention, the filter may or may not be used with the auxiliary source chambers 502, 504. By controlling the plasma density of the auxiliary source chambers 502, 504 and the combination ratio of the plasma, the relative seed density in the main processing chamber 102 can be controlled. However, by interposing a filter between one of the auxiliary sources 502, 504 and the main chamber 512, the main processing chamber 51
The control of the seed density within 2 can be further enhanced. That is, one chamber will generate primarily charged particle species, or a predominantly selected charged particle species, while another
One chamber may generate one of the predominantly neutral species and may be one of the ways to allow control of the main density.

Another source of neutral radicals formed by some other means may be utilized to control the seed density in the processing chamber. For example, thermal dissociation may be used to generate or transport neutral radicals into the processing chamber.

The workpiece is exposed to the processing plasma and other processing gases in the main chamber. Although not currently shown in FIG. 1, it is preferable to apply a capacitive bias power to the main chamber to adjust the charged particle or ion energy applied to the workpiece.

Because there are many possible combinations of process gas, generated species and plasma assisted processes, the method of controlling neutral and charged particle species separately is limited to the specific embodiments disclosed below. Not something. The following specific examples illustrate possible embodiments for performing the method of the present invention. However, the present invention
It should not be limited to the specific examples or embodiments described below.

Presently Preferred Embodiments of the Present Invention (FIGS. 2A-10) The present invention provides individual control of plasma species density to optimize processing characteristics. The present invention is for separately controlling the density of neutral particle species for all or selected charged particle species. It also provides control of the density of the first charged particle species relative to the second charged particle species. The main density in the processing plasma may be determined by, among other things, the auxiliary plasma seed density, the choice of filter and the seed density of the plasma generated in the main chamber. Due to the various types of known plasma reactors, several possible types of particle filters, and various types of workpiece processing techniques, there are several possible embodiments of the present invention that can control seed density.
FIGS. 1, 3, 4, 6, and 7 show, for example, some non-limiting variations of the presently preferred embodiment of the present invention. 2A to 2F show some non-limiting variations of the auxiliary source chamber of the present invention. 5A, 5B, 8A to 8D,
FIG. 7 illustrates some non-limiting variations of filters utilized in some embodiments of the present invention.

Referring to FIG. 1, control of the charged particle density in the plasma and etchant gas or other types of neutral particles in the plasma of the main processing chamber 102 of the plasma reactor 100 as proposed by the present invention. Separate control of the density is achieved by combining an auxiliary source chamber 104 with the reactor, as shown in FIG. This auxiliary source chamber 104 is located outside the main processing chamber 102 of the reactor.

The auxiliary source chamber 104 has a radiant energy applicator 112 capable of illuminating the interior of the source chamber and forming a plasma from the process gas flowing therethrough. The applicator 112 may be of the type that irradiates the interior of the auxiliary supply chamber 104 and ignites the plasma using any of a microwave discharge, an inductive discharge, or a capacitive discharge. Also, the auxiliary source chamber 104 may be cooled by any suitable conventional temperature control device (not shown) so as to not overheat and damage the chamber when the plasma is ignited in the chamber. Is preferred.

Auxiliary source chamber 104 includes a process gas source 1 that will contain an etchant gas.
10 at its inlet and furthermore the gas distribution device 10 of the main processing chamber 102.
6 at its outlet.

The etchant gas or other process gas, which was previously a part of the process gas directly supplied into the main process chamber 102 of the reactor, is now in the auxiliary source chamber 10.
Requested first through 4. In the embodiments of the invention described herein, the remaining composition of the processing gas is supplied into the main processing chamber 102 in a conventional manner.

A plasma is formed in the auxiliary source chamber 104 from the gas flowing therethrough. The gas decomposes in the plasma to form, inter alia, neutral and charged particles.

The decomposition gas of the neutral particles and the charged particles formed in the auxiliary supply chamber 104
It exits the auxiliary source chamber 104 and enters the main processing chamber 102 where the other composition of the processing gas is mixed. The two gas components are separated by separate gas distribution devices (
Although not selectively supplied to the main chamber 102 via a not-shown), it is preferred that such mixing occur in a manifold of a conventional gas distribution device 106 capable of supplying a combined gas into the main chamber.

In the embodiment of FIG. 1, plasma generated in the auxiliary source chamber 104 is supplied into the main processing chamber 102 via a neutral source chamber conduit 108. During transition from auxiliary source chamber 104 to main processing chamber 102, conduit 1
Via 08, the charged particles generated by the plasma in the auxiliary source chamber recombine to form neutral particles or etchant gas molecules.

The neutral particle source chamber conduit 108 has an inside diameter and length that ensures that neutral particles are nearly perfect when reaching the main processing chamber 102, but that almost all charged particles are gone. Have. This is possible because the neutral particles of the etchant gas are relatively stable compared to the charged particles. However, if the conduit is very long or the cross-sectional area is very small, the neutral particles may recombine into etchant gas molecules. On the other hand, if the conduit is very short or the cross-sectional area is very large, most of the charged particles can reach the main processing chamber of the reactor.

If the tubular conduit has an inner diameter of about 2.5 cm and a length of about 0.5 m,
Charged particles can be almost completely eliminated from gases introduced from the neutral particle source chamber into the main processing chamber. Of course, good results can be obtained with other sized conduits. Important design criteria in embodiments of the present invention are:
The gas reaching the chamber contains a desired concentration of neutral particles of the etchant gas;
Another goal is to minimize the concentration of charged particles as much as possible. Any size of conduit capable of generating these concentrations is applicable.

The neutral particle source chamber conduit 108 is preferably made of a single material or formed in a straight line of a material that is resistant to the bombardment of neutral and charged particles of the process gas flowing therethrough. For example, if the process gas contains chlorine in an etchant gas that generates Cl neutrals, the conduit is formed of protective Teflon or is thereby formed in a straight line.

By using an appropriately sized neutral particle source conduit, most of the gas entering the main chamber 102 from the auxiliary source chamber 104 will have some amount of etchant gas molecules and neutral particles of the etchant gas. Become. Since the charged particles have been found to recombine almost completely regardless of the speed at which the gas travels through the conduit, for example, at least at a flow rate consistent with the plasma assisted etching process, the auxiliary source chamber 104 to the main processing chamber Note that the flow rate of the gas flowing to 102 is not critical.

FIG. 2A shows an embodiment of an auxiliary source chamber 200 configured to form a plasma using a microwave discharge. In this embodiment, the source chamber 20
0 is an applicator tube 20 preferably made of a dielectric material such as sapphire.
2 inclusive. The applicator tube 202 is connected at one end to a gas supply (not shown) via a suitable inlet supply line 204 and further includes a neutral particle source chamber conduit 20.
6 at the other end, which is connected to the inlet of the main processing chamber of the plasma reactor. Applicator tube 202 passes through microwave source 208 at a location between inlet supply line 204 and conduit 206. The microwave source 208 generates a plasma in the applicator tube 202 as the gas travels from there to the main processing chamber.

FIG. 2B illustrates an embodiment of an auxiliary source chamber 300 configured to form a plasma using an inductive discharge. The chamber 300 has a circular top 302 and a bottom 304, and a cylindrical side wall 306. Induction coil antenna 308 is in chamber 3
00, a radio frequency (RF) plasma power generator 31
0 through an impedance matching circuit 312 to supply RF power into the chamber. The sidewall 306 is preferably made of a dielectric or semiconductor material and does not significantly impede the transfer of RF energy into the chamber.

Processing gas is introduced into the auxiliary source chamber 300 via an inlet line 314 from a conventional gas source (not shown). Process gas is decomposed in chamber 300 and exhausted via neutral source chamber conduit 316. Conduit 316 is connected to the inlet of the main processing chamber, as described above.

The above described chamber structure is shown for illustrative purposes only. Many other chamber configurations are possible as well. For example, the auxiliary source chamber has a domed top similar to the main processing chamber of many commercially available plasma reactors. (As described below, FIGS. 2D, 4, 6, and 7 show an embodiment of an auxiliary source chamber having a dome-shaped top.) The coil antenna of such a dome-shaped reactor is a dome It may surround all or part of the top of the shape.

Also, basically, any known chamber structure used for the main processing chamber of a plasma reactor can be used in fabricating the auxiliary source chamber associated with the present invention.

FIG. 2C is another embodiment of an auxiliary source chamber 300 configured to form a plasma using an inductive discharge to form a helicon wave. The embodiment of FIG. 2C has an inductive antenna 308 looped around a chamber wall 306 near the top 302 and near the bottom 304. The antenna has R in two loops
It is provided so that the phase of the F current is shifted by 180 degrees to propagate the helicon wave. The inner and outer electromagnets 309A and 309B are located around the outer wall 306 of the antenna 308. The electromagnets 309A and 309B act to enhance the induction plasma generation in the auxiliary chamber 300.

FIG. 2D shows another embodiment of the inductively coupled auxiliary source chamber 300. FIG.
In the embodiment of D, the top 302 is dome-shaped. As shown in FIG. 2C, the dielectric antenna 308 is wound in a loop around the chamber wall 306 near the top 302 and near the bottom 304, and the helicon wave is shifted 180 degrees out of phase between the RF currents of the two loops. Is provided. Inner and outer electromagnets 309A and 30
9B is located outside the inductive antenna and around the wall 306 of the auxiliary chamber 300 to enhance the generation of inductive plasma. This embodiment of the auxiliary source chamber 300 is commonly referred to as a magnetically enhanced inductively coupled plasma reactor, or a MEICP reactor. It is preferred to operate this type of reactor with helicon waves at m = 0.

In the embodiment of FIG. 2D, an inlet line 314 is shown attached to the dome-shaped top 302, and a conduit 316 is shown extending from the bottom 304 of the chamber 300. Conduit 316 may be connected to the inlet of the main processing chamber, as described above. This configuration provides a more laminar flow of processing gas and plasma via the auxiliary chamber 300, which in some embodiments allows the plasma to be more directly supplied directly to the main processing chamber 102.

FIGS. 2E and 2F show an embodiment of an auxiliary source chamber 400 configured to form a plasma using capacitive discharge. The exterior of the chamber 400 has a circular top 402 and bottom 404 and a cylindrical sidewall 406 in FIG.
B and similar to the chamber of FIG. 2C. Processing gas is introduced into the auxiliary source chamber 400 via an inlet line 408 starting from a conventional gas source (not shown). The gas once decomposed in the chamber 400 is exhausted through the aforementioned auxiliary source chamber conduit 410 connected to the main processing chamber inlet.

The chamber 400 has a pair of electrodes 412 and 414 instead of an induction coil antenna.
Is different from the above-described embodiment of the inductive discharge. In the first capacitive discharge embodiment shown in FIG. 2E, these electrodes 412, 414 are in the chamber 400 and face each other to form a plasma forming region therebetween. Electrode 41
2, 414 are electrically connected to the opposite side of the plasma power generator 416. Since the electrodes 412, 414 are in the chamber 400, the lid 402, the bottom 404
And the sidewalls 406 may be of any suitable material, including dielectric or semiconductor materials, or of a metal such as aluminum or stainless steel.

In the alternative capacitive discharge embodiment shown in FIG. 2F, the electrode 412
'414' are located on both sides outside the sidewall 406 of the chamber 400 'and face each other to form a plasma forming region within the chamber. The electrodes 412 'and 414' are connected to a plasma power current generator 416, as in the first embodiment shown in FIG. 2E. However, because the electrodes 412 ′, 414 ′ are outside the chamber sidewall 406, the sidewall is made of a dielectric or semiconductor material so as to not significantly impede the transfer of RF energy into the chamber.

FIG. 2A to FIG. 2F show examples of the auxiliary chamber of the present invention. Other shapes or power sources may be utilized for the auxiliary chamber of the present invention. For example, it is also possible to use a power supply such as an ultraviolet ray or an electron beam. As mentioned above, basically any known chamber structure used for the main processing chamber of a plasma reactor can be used to manufacture the auxiliary source chamber associated with the present invention. .

Referring to FIG. 4, the auxiliary source chamber 300 of the present invention, shown in FIG. 2D, includes a main processing chamber 10 having an inductive coil antenna located above the dome top.
2 is attracted via conduit 316. The dome-shaped top 602 of the main processing chamber 102 can carry a filtered auxiliary plasma near the power applicator 608 of the main processing chamber 102. To generate or maintain a main chamber plasma (not shown) in the main processing chamber 102 from a plasma or other processing gas (not shown) supplied by an auxiliary source chamber introduced into the main processing chamber 102, An applicator 608 may be used. The power supply applicator 608 may be an inductive antenna as shown in FIG. 4 or another type of power supply applicator such as a microwave, ultraviolet, electron beam capable of generating a plasma. A capacitive bias 612 may be applied to the workpiece 610 via the platform 614 to control the charged particle energy flux to the workpiece 610. In this way, the plasma density, charged particle energy and seed density may be individually controlled.

In these embodiments, the addition of an auxiliary source chamber and conduit to the plasma reactor has the effect of separating the control of the neutral particle density and the control of the charged particle density of the etchant gas. Auxiliary source chambers and conduits may be used to introduce a sufficient amount of neutral particles of the etchant gas into the main processing chamber to form a desired density therein. This is a control group of auxiliary source chamber parameters, i.e., power input level, process gas flow rate, desired amount of etchant gas neutral particles can be generated and supplied to the main chamber. It may be achieved by setting the level. At the same time, the same control parameters associated with the main processing chamber may be set so that the charged particles therein generate the desired density. Thus, basically, the density of the neutral particles of the etchant gas is determined by controlling the aforementioned parameters associated with the auxiliary source chamber, and the density of the charged particles controls similar parameters associated with the main processing chamber. Is determined by

The plasma ignited in the main process chamber may be from “raw” etchant gas introduced into the main chamber with other process gases, or from etchant gas molecules reaching the main chamber from an auxiliary source chamber. Either way, it goes without saying that a certain amount of neutral particles of the etchant gas other than those supplied from the source chamber may be generated. The neutrals of these additional etchant gases are taken into account when setting the control parameters associated with the source chamber,
The combined amount of neutral particles of the etchant gas will be approximately equal to the overall desired density in the main processing chamber.

Given the reactor and processing method described above, if there is between a rich mixture of neutral particles and a rich mixture of ions, changing the composition of the plasma formed in the main processing chamber Can also.

By setting the control parameters of the main chamber relatively low, a concentrated plasma of neutral particles may be formed in the main processing chamber. At low levels, little ionization of the process gas introduced into the main chamber occurs. Therefore,
The density of charged particles in the plasma will be very low. It goes without saying that almost no dissociation occurs. However, the neutral particles of the etchant gas previously supplied to the main chamber by this dissociation are now supplied from the auxiliary source chamber. The end result is a plasma that is very rich in neutrals but has a very low density of charged particles. Such a concentrated plasma of neutral particles is advantageously used in many etching processes. For example, an isotropic etching process that requires an extremely high degree of etching selectivity is achieved using a neutral particle rich plasma.

A concentrated plasma of ions or charged particles is formed in the main processing chamber with little or no etchant gas introduced into the main processing chamber. Instead, other process gases are used to form the plasma. These other gases generate charged particles and non-reactive neutral particles. For example, such a processing gas includes argon. The level of the control parameters of the main processing chamber parameters is sufficient for the ionization of the processing gas, causing the plasma to generate the desired charged particle density. In this case, the desired density of neutral particles of the etchant gas, which is relatively small, is supplied from the auxiliary source chamber to the main chamber. The control parameters associated with the source chamber are set to ensure that the desired low amount of neutralizing etchant gas is supplied to the main chamber. The end result is a plasma that is very ion-rich, but has a very low neutral particle density of the etchant gas. Such an ion-enriched plasma is advantageous when used in a process for etching a dielectric material, such as SiO ₂ , SiN or undoped silicon, from a workpiece.

By changing the control parameters of the main chamber and the source chamber, and also by changing the amount and type of process and etchant gases supplied from each of the above to each chamber, in particular, the density of the neutral particles of the etchant gas Any combination of and the density of charged particles can be made in the plasma of the main chamber.

Also, by adding an auxiliary source chamber to the plasma reactor, a number of processing advantages can be obtained over the general method of separating the neutral and charged particle densities of the etchant gas described above. Can be For example, oxygen or nitrogen may be introduced into the main processing chamber to form neutral particles that react with silicon to form etch resistant deposits on certain surfaces of the workpiece, such as those used during silicon etching. The described passivation process can be further improved by using an auxiliary source chamber in conjunction with a plasma reactor incorporating the present invention. In etching processes where it is desirable to keep the density of charged particles in the plasma of the main chamber to a minimum, for example, at very high power input levels, the opposite effect occurs as some of these gases ionize. These gases may instead be introduced into the auxiliary source chamber to prevent the formation of disadvantageous charged particles from oxygen and nitrogen. In this way, oxygen and nitrogen gases decompose in the source chamber to form neutral and charged particles. The neutral particles of oxygen or nitrogen are then fed into the main processing chamber of the reactor, which reacts to form a deposit that is resistant to the desired etching. However, oxygen and nitrogen are recombined while passing through the neutral source conduit and do not reach the main processing chamber where they can adversely affect the etching process. Such an improved passivation method can also simultaneously generate neutral particles of the etchant gas in the neutral particle source chamber, if necessary.

Examples of the improved passivation process as described above are not limited to this. It will be apparent to those skilled in the art from this description that any process gas may be decomposed in the auxiliary source chamber and supplied to the main process chamber without adding additional charged particles to the main chamber plasma. Thus, in essence, the neutrals of any process gas can be separately controlled from the density of the charged particles associated with the gas using the auxiliary source chamber.

It should be noted that this may cause problems with the above-mentioned proposals in which the etchant gas and other process gases are simultaneously introduced into the auxiliary source chamber and disassembled together before being fed into the main chamber of the reactor. I want to. For example, in that the control parameter levels required to generate the desired neutral particle density of the etchant gas in the main processing chamber do not generate the desired density of other processing gas neutral particles. is there.

In such a case, two or more auxiliary source chambers are combined in a plasma reactor. In this configuration, individual auxiliary source chambers, such as the two chambers 502, 504 shown in FIG. 3, are separately connected to the gas distribution device 510 of the main processing chamber 512 of the reactor 500.

Further, each chamber is connected to a separate gas supply source 506, 508. The auxiliary source chamber allows the user to separately control the density of neutral particles in the main chamber1
It is supplied with one or more gases. Thus, in the above example, the etchant gas is supplied via the first auxiliary source chamber 502 and the oxygen or nitrogen is supplied via the second source chamber 504. Two source chambers 502,
Control parameters, each associated with 504, are set to a level that produces the desired neutral density of the gas in the feature flowing through the chamber.

Thus, with two such gases of interest, two auxiliary source chambers are used. Further, if it is desired to control the density of the neutral particles of the three gases in this manner, three auxiliary supply chambers are used, and so on.

Referring to FIG. 5A, as described above, the conduit filter 316 may be of various sizes to provide a desired level of charged particle filtering. Also, other embodiments of the filter 316 of the present invention can be used.
As shown in FIG. 5B, several conduits 316 can be used in parallel to filter charged particles. In this manner, the conduit filter 316 is combined with the other conduits 316 to form the filter 3 including the plurality of conduits 316.
16 'may be formed.

FIG. 6 is a diagram illustrating a plurality of conduit filters 316 ′ interposed between an inductively coupled magnetically enhanced auxiliary source chamber 300 and an inductively coupled main processing chamber 102. A filter 316 ′ comprising a plurality of conduits 316 may be used to remove any charged particles from the auxiliary plasma generated in auxiliary source chamber 300. Charged particle species are then generated in the main chamber or, as shown in FIG. 5, without the use of conduit filter 316, multi-conduit filter 316 'or other recombination type filters. Generated by a second auxiliary source chamber coupled to

The present invention can also filter charged particles using other embodiments of the recombination type of filters 316 and 316 ′. For example, the grounded neutralizing grid 316a shown in FIG. 7A may be used to filter charged particle species from the auxiliary source plasma before entering the main processing chamber. The neutralizing grid has an opening 702 that allows filtering of charged particle species while passing neutral species of the auxiliary plasma.

Referring to FIG. 7B, as an alternative to the grounded neutralizing grid filter 316a of FIG. 7A, a voltage source 710 shown in FIG. 7B is applied to the grid filter 316b to provide either a positive or negative charged particle species. Can be selectively recombined. For example, the recombination grid 316b can be negatively charged such that positively charged species are removed from the auxiliary plasma or neutralized with electrons. In this way, the charged particles of the auxiliary plasma can be carried into any of the main processing chambers after being filtered according to their charge.

It is also possible to form a grid type filter made of a dielectric type material for filtering seeds. Such filters may filter species via surface recombination. In addition to the embodiment shown in FIGS. 7A and 7B, the outer shape of the filter may be modified to enhance such an effect. In such a case, the grid type filter may be provided without the set potential. In addition to varying the species concentration within the processing chamber, this type of filter may be used to keep deposition elements from flowing into the auxiliary source chamber.

Another possible filter device is an electric field filter. Such filters may be used to filter charged particles by charge or mass. For example, a plate or rod may be inserted either externally or internally between the auxiliary source chamber and the main chamber to create an electrostatic field. In this way, charged particle species generated in the auxiliary chamber can be prevented from entering the main processing chamber.
In addition, an RF electric field filter may be used to filter home appliance particle species by charge and mass. As with the electrostatic filter, a plate or rod may be inserted either externally or internally between the auxiliary source chamber and the main chamber to form an RF electric field filter. In this way, the charged particle species of the auxiliary plasma may be filtered into charge or into charge and mass and delivered to the main processing chamber.

Referring to FIG. 7C, a quadrapole filter device 316c is an example of an electric field filter used to filter charged particles from the auxiliary plasma and bring them into the main processing chamber. A quadraol filter 316c, similar to the type used in mass spectrometers, may be interposed between the auxiliary source chamber and the main processing chamber. Quadrapole filter 316c may be used to filter charged particle species by their mass.

The electric field filter of FIG. 7C may generate an electrostatic field, an RF electric field, or a combination thereof. Using the quadrapole filter 326c, the rod 75
By applying a potential to Oa, 750b, 750c, and 750d to generate an electrostatic field and an RF electric field (not shown), the charged particle species are separated. Appropriate DC bias and current phase are selected and rods 750a, 750b, 750c, 750
The strength and phase of the electric field in d avoids selected charged particles passing according to mass and charge.

Usually, four rods 750a, 750b, 750c, 750d are used, but conductor plates or other shapes or other types may be used. Further, FIG.
Has four bars, but the electric field filter of the present invention is not limited to four poles. Any number of rods may be used to form the electric field filter of the present invention.

[0097] The selected charged particle species or all may be filtered using the electric field filter 316c of FIG. 7C. That is, the density of one charged particle species may be adjusted with respect to another charged particle species using the filter 316c.

[0098] Filtering of one charged particle species can be used to improve workpiece processing.
May be used. For example, in a metal etching process, Cl⁺And Cl_Two ⁺ It is believed that the ratio may reduce metal residues in the main processing chamber. The magnitude of the electric field is some or all of Cl_Two ⁺Seeds from auxiliary plasma
Filtered and all Cl⁺The species are selected so that they can pass through the main chamber. By selecting the filtering of charged particle species, the main processing plasma
The seed density in the inside can be controlled better.

Referring to FIG. 7D, the present invention may use a magnetic field filter 316d for filtering the auxiliary plasma. A magnetic field filter 316d may be interposed between the auxiliary source chamber and the main processing chamber to serve to deflect the charged particle species. As the permanent or electromagnet 770 flows in the direction of the main processing chamber, it generates a magnetic field 316d having lines of magnetic force 772 orthogonal to the path of the auxiliary plasma. The magnetic field filter generates a magnetic force F acting on the charged particles according to the following equation.

[0100]

(Equation 3)

This magnetic force can be used to deflect any charged particles that proceed toward the main chamber and return toward the auxiliary chamber, thereby preventing charged particles from entering the main processing chamber.

Also, the type of feature can be selected by selectively filtering the type of charged particles by the charge-to-mass ratio using a magnetic filter. Appropriate treatment of the magnetic field strength allows the charged particle species to be selectively filtered by charge-to-mass ratio because larger charged particle species have greater momentum in the plasma stream. For example, the magnitude of the magnetic field to deflect large molecular charged species returning to the auxiliary source chamber may be smaller than that required to deflect less electrons. The magnitude of the magnetic field is selected to divert larger species, such as molecularly charged species, but to pass smaller species, such as electrons, through the species source chamber. Although charged molecular species and electrons have been described for purposes of explanation, it is also possible to selectively filter charged molecular species using a magnetic filter. In this manner, the density of one charged species may be adjusted for another or several other charged species by magnetic filter 316d selectively filtering charged particles by charge-to-mass ratio.

Although a single electrostatic field is depicted in FIG. 7D, other embodiments of the filter of the present invention may use several magnetic fields or may utilize a time-varying magnetic field. .

The various filter types described above may be combined to further filter the auxiliary plasma before entering the main processing chamber. Any combination of filter types may produce the desired seed density in the main plasma. For example, the quadrapole of FIG. 7C may be coupled in series with the conduit of FIG. 5A or 5B in a single auxiliary source chamber. Also, a quadrapole may be used to pass some selected charged species through a conduit filter. The conduit filter then generates the selected neutral species by recombining the selected charged species. In this manner, the present invention may be used to supply a selected neutral species, such as a neutral radical, to the main chamber to adjust the density of that species. The charged particle species may be carried into the main chamber by another auxiliary chamber, or may be generated in the main processing chamber using the power supply of the main chamber.

The foregoing description is by way of example only, any electric, magnetic or electrostatic or electrostatic field type with a recombination type, any electrostatic field type with any magnetic field type, multiple of the same type Other combinations of filters and filter types, such as filters, may be used to control the seed density in the main processing chamber.

Referring to FIG. 8, as described above, the present invention is not limited to the generation of neutral species in the auxiliary chamber 300. The auxiliary chamber 300 may generate both neutral species and charged species. Alternatively, the main chamber may be used to generate mainly charged species. The species generated in the auxiliary chamber 300 may be filtered and provided to the main processing chamber 102 to control the seed density of the main processing chamber. Further, multiple auxiliary source chambers or the main processing chamber itself as shown in FIG. 3 may be added to the particle species in the processing chamber.

As described above, by interposing one or more filters at reference numeral 816, in addition to supplying neutral particles to the processing chamber, the present invention can be used to selectively charge charged particles. It may be filtered. In some applications, the auxiliary chamber 3
00 or one of several auxiliary chambers may be required to supply primary charged particles to the processing chamber 102. In such a case, the input parameters of the auxiliary chamber 300, such as power supply, temperature and pressure, are selected such that the auxiliary source chamber generates the main charged particle species.

The auxiliary plasma, consisting of the main charged particle species, may then be filtered, as described above, by inserting one or more filters at reference numeral 186, or not at all. This may provide the main processing chamber 102 with a desired density of charged particle species. Alternatively, or in addition to filtering, the primary processing chamber 102 or another auxiliary source chamber is used to generate or supply the desired neutral species, as depicted in FIGS. You can also.

If the auxiliary source chamber 300 is selected to supply charged particle species to the main processing chamber, it may be embodied as a magnetically enhanced inductively coupled reactor, as shown in FIG. An advantage of MEICP is that the ionization rate can be close to 100%. Such charged particle-rich plasma can be supplied directly to the main processing chamber as a charged particle species source.

Alternatively, the auxiliary plasma generated by the auxiliary supply chamber may be selectively filtered and then transferred to the main processing chamber 102 so that the auxiliary plasma is mainly composed of one kind of charged particles. Another option is to filter the auxiliary plasma, which is primarily composed of charged particles, using the multiple filters described above, so that the selected charged species recombine to generate primarily one neutral species. , To the main processing chamber 102.

While the benefits of MECIP can be beneficial in some processes, using an auxiliary source chamber embodiment to vary the density of charged or unfiltered charged particle species fed into the main processing chamber. May separately control the seed density in the main processing chamber. The invention applies to all types of plasma reactors or plasma-assisted reactors.

FIG. 8 shows a process gas inlet line 314 ′ in the main chamber 102. Process gas inlet line 314 ′ may carry process gas to main chamber 102. The process gas may be ignited by the inductive antenna 608 to form a plasma in the main chamber. The plasma generated in the auxiliary chamber 300 is combined with the ignited processing gas introduced into the main chamber 102 to form a processing plasma in the main chamber 102.

The embodiment of FIG. 8 shows a dome-shaped ceiling 602, an induction antenna 608, and a table 61.
Although shown as having a capacitive bias 612 applied to the workpiece 610 via 4, the invention applies to all types of plasma reactors or plasma assisted reactors. Further, in conjunction with other embodiments of the present invention, the embodiment of FIG.
May or may not supply power. Similarly, embodiments of the present invention may or may not employ a filter to provide seed density control within the processing chamber 102. further,
Several auxiliary chambers and processing gas sources may be used to control seed density and workpiece processing. Therefore, the processing gas is supplied to the auxiliary source chamber 30.
It may be supplied to both zero and main chambers 102, only main chamber 102, only auxiliary source chamber 300, or only multiple auxiliary source chambers. Each of the multiple auxiliary chambers may or may not use a different type of filter to generate the desired main processing chamber plasma.

Referring to FIG. 9, the present invention may use two or more auxiliary chambers to control seed density within main processing chamber 102. FIG. 9 shows two auxiliary source chambers 502,504. Each auxiliary source chamber 502, 504 generates a different species so as to generate a desired seed density in the main processing chamber 102 by combining the two plasmas generated in the auxiliary source chambers 502, 504. Is also good.

As with the other embodiments described herein, in the embodiment of FIG. 9, the main processing chamber 102 may or may not have a power source. The main processing chamber 102 of FIG. 9 has inductive coil antennas 608 and 708 positioned around the main processing chamber 102. By providing power to the main processing chamber 102, the control of seed density may be better. The power source may be an inductive antenna 608, 708, or may be of another type or structure of the power source.

The embodiment of FIG. 9 may use one or more charged particle filters.
A filter may be interposed between the auxiliary source chamber 502 or 504 and the main chamber 102 at reference numeral 916 or 917. Providing at least one filter in either of the auxiliary source chambers 502, 504 may provide better control of seed density.

The embodiments of FIGS. 1, 3, 4, 6, 8 to 10 provide a non-limiting means of controlling the density of charged and neutral particle species without adjusting the density of the processing plasma. . By controlling the seed density of the auxiliary source plasma entering the processing chamber, by controlling the seed density of the plasma in some auxiliary source chambers, or simultaneously with controlling the plasma generated in the main chamber By controlling the seed density of the incoming auxiliary source plasma, the present invention separately controls the seed density.
In addition, the full density of the plasma may be maintained or otherwise conditioned in a single chamber apparatus. Further, bias power may be applied to the workpiece to individually control the ion energy, or otherwise affected by adjusting the seed density within the main processing chamber. That is, according to the present invention, the control of the seed density and the control of the plasma density and the ion energy can be separately performed.

As mentioned above, according to the present invention, by individually controlling the seed density in the plasma, for example, etching rate, selectivity, etching feature profile, etching rate microloading and removal of etching residues, etc. Processing characteristics can be better controlled. In the example of an etch metal residue described above, the ratio of Cl ⁺ to Cl ₂ ⁺ may affect the concentration of the metal etch residue in the main processing chamber 102. Thus, by selectively reducing the amount of Cl ⁺ relative to Cl ₂ ⁺ , the concentration of metal residues may be reduced in the main processing chamber. By reducing the concentration of metal etch residues, metal residues do not degrade processing and reactor components by depositing on workpiece surfaces and chamber surfaces.

The present invention may also be used to remove metal etch residues by a variety of other methods. An auxiliary source chamber may effectively remove or eliminate such ions in the main processing chamber by generating ligands and surrounding metal ions etched into the processing chamber. For example,
It is introduced into the ligand main processing chamber, such as C = 0, by enclosing the remaining Tomebutsu metals, such as Cu ^+, to effectively remove the Cu ⁺ main processing chamber. Of course, other ligands can be used and other types of metal ion residues may be removed in this manner.

It should also be noted that it is not necessary to generate a plasma to generate the ligand. The ligand may be generated in any conventional manner known to those skilled in the art and supplied to the main processing chamber. Thus, an auxiliary source chamber may be used to supply the selected charged particle species to the main processing chamber, and other devices or methods such as thermal dissociation may be used to load the ligand into the main processing chamber.

Yet another example illustrating one of the possible methods of using the present invention to improve processing characteristics is to introduce a polymer into the processing chamber during SiO ₂ etching. Polymers can be used to provide a passivation layer to improve the aforementioned etch rates, selectivity and etch feature profile characteristics.

Typically, a polymer gas, such as C ₂ F ₈ , is introduced into the main chamber and dissociated with other process gases, along with other neutral and charged species in the main process chamber,
To form the desired passivation polymer CF _2. This adds other species, such as F, e, F ⁺ , to the charged particle and neutral radical densities in the main processing chamber. Thus, in addition to adding passivation species, dissociation of C ₂ F ₈ adds other species that are reactive to the processing plasma.

This can sometimes be prevented by using the present invention. According to the present invention,
As described above, the primary processing plasma is formed by generating an auxiliary plasma having a selected or filtered species density, and without applying power to the primary processing chamber, the primary source plasma is generated. It may be introduced into the chamber. The desired polymer gas species may be separately introduced into the main processing chamber to combine with the filtered auxiliary chamber plasma or the unfiltered one in the main processing chamber. Using this approach, the density of CF ₂ may be increased without adding to the neutral and charged species generated by the main processing chamber power supply. In this manner, the processing characteristics may be enhanced by separately controlling the processing plasma seed densities.

The CF ₂ may be supplied to the main processing chamber in various ways. As mentioned above, substantially all may be supplied by another auxiliary chamber by generating, for example, an ionized plasma, filtering by charged particle species and recombination. Alternatively, it may be supplied using other conventional techniques such as thermal dissociation.

[0125] Thermal dissociation techniques may be used to generate any desired neutral species without a main processing chamber. For example, thermal dissociation, such as used in a chamber for vapor phase growth, may be utilized to provide neutral species. Thus, the present invention is suitable for use in a plasma assisted chemical vapor deposition chamber.

The present invention may also be used to generate a substantially pure source of neutral or charged particle species. For example, a magnetically enhanced inductively coupled embodiment of the auxiliary chamber may be used to generate substantially all of the ionized plasma. The ions or charged particles may then be filtered, as described above, and used to generate an ion source that includes substantially one type of charged particle. The ion source may be transported to a processing chamber.

Alternatively, the substantially one kind of charged particles may be combined with another different source of a substantially pure charged particle species having the opposite polarity to form a substantially pure neutral species gas. May be. Alternatively, substantially all of the ionized particles are filtered as described above, leaving only one type of positively charged particles,
This may be filtered and recombined to form a substantially pure neutral species gas. Alternatively, substantially all of the ionized plasma may be filtered so that only one type of positively charged particle and a different type of electron remain. Then, by filtering these two species,
The two species may recombine to form a substantially pure neutral species gas.

Thus, the present invention provides a number of methods for controlling seed density. Further, the present invention improves plasma assisted and other types of workpiece processing.

Referring to FIG. 10, as noted above, the primary processing chamber of the present invention is not limited to any particular structure. FIG. 10 shows yet another non-limiting example of separately controlling seed density. The main processing chamber 102 has a flat top 602 'and an inductive antenna 608 thereon. As in the embodiment of the main processing chamber 102, it surrounds the inductive antenna or, alternatively, the side wall of the main processing chamber 102 not shown in FIG. Workpiece 61
In order to control the ion energy at zero, a capacitance bias 612 is
May be applied. At position 816, a filter may be interposed between the main processing chamber 102 and the auxiliary source chamber 300 to further control the seed density as described above.

[0130] The distance of the workpiece 610 to the plasma generation of the auxiliary source 300 may be set to further control the process. For example, if the density of the auxiliary source plasma near the workpiece 610 needs to be reduced, the distance from the auxiliary source plasma generation to the workpiece may be increased. Alternatively, as another non-limiting example, a recombination filter may be used at 816 to ensure that neutral radicals reach workpiece 610 before binding, if desired. The processing may be enhanced by reducing the distance of the auxiliary source plasma generation from 610. This may be achieved by setting the height of the top 602 'on the workpiece 610, for example, setting the height of the sidewalls of the main processing chamber 102. Alternatively, this may be achieved by setting the height of wall 306 of auxiliary source chamber 300. Additionally, the platform 614 may be adjusted to set the distance of the workpiece 610 with respect to the plasma generation in the auxiliary source chamber 300.
Other embodiments of the present invention may use these features to facilitate processing.

FIGS. 4, 6, 8 to 10 show an auxiliary chamber using a power supply applicator capable of generating helicon waves to generate an auxiliary plasma. Although any type of mains power applicator may be used to generate the auxiliary plasma, among other advantages, the mains power applicator capable of generating helicon waves may be used over a wider range of temperatures and pressures. It is possible to generate a uniform high-density plasma in the auxiliary chamber. This allows the present invention to be used with very wide processing windows for etching and deposition.

For some properties and examples of helicon waves, see February 5, 1991, 19
Registered on June 6, 1995 and July 4, 1995, respectively, all "High Density Plasma Deposition and Etching Equipment (High Density Plasma)
U.S. Patent Nos. 4,990,229, 5,421,891, and 5,4, all to Campbell et al., Entitled "Deposition and Etching Apparatus".
No. 29,070, the entire contents of which are incorporated herein by reference.

The bell chamber 3 is typically used to form an auxiliary chamber power supply applicator.
A double loop antenna 308 is arranged around the cylindrical portion 06 to generate a helicon wave of m = 0. The RF supply generator 310 passes current through one loop in a clockwise direction and current through the other loop in a counterclockwise direction so that each of the loops has a current that is 180 degrees out of phase. Flow. Also, in this embodiment, the auxiliary power applicator includes a tight combination of electromagnets 309a and 309b that create an axial magnetic field in the auxiliary chamber 300. The current of the inner magnet 309a and the outer magnet 309b may be adjusted to supply a magnetic field that is immediately dispersed outside the cylindrical portion of the auxiliary chamber.

The axial magnetic field of the auxiliary chamber directs the plasma to the processing chamber and is dispersed within the processing chamber. Also, such dispersion allows the magnetic field to be maintained at a location remote from the workpiece.

The interaction of the axial magnetic field and the induced RF electric field within the barrel increases the helicon wave in the auxiliary chamber. Helicon waves are typically 10 minutes from the junction of the auxiliary and processing chambers, depending on their relationship to scattering and also Landau attenuation.
Propagating into the processing chamber in the direction of the workpiece at a distance of more than 1 cm.
As mentioned above, this distance can be adjusted to optimize the processing and will depend on the processing parameters selected.

The auxiliary chamber 300 is made of quartz and has an optimal distance between loops such that the time from the induced helicon wave propagating between the two loops is １ ／ of the RF period.
It may have a distance of 0 cm (about 12.5 cm at 13.56 MHz)
. The auxiliary chamber has a wide range of RF power (0.5 to 3.0 kW), magnetic field strength (
30 to 300 G) and pressure (0.5 to 50 mT). The auxiliary chamber is not limited to the above-described layout for generating the helicon wave of m = 0. Also, using another antenna structure, for example, m
Other modes of the helicon wave such as = 1 may be generated to form the auxiliary plasma.

An advantage of the helicon source is that by adjusting the plasma parameters, the helicon wave source power applicator approaches ionization rates close to 100%. This has advantages over other types of mains power applicators if the auxiliary chamber is selected to supply the main charged particles to the main chamber with or without filtering. In addition, a high ionization rate is an advantage if the auxiliary chamber is selected to generate neutrals using a recombination type filter. A high ionization rate makes it easier to generate more than the desired plasma species and supply it to the main chamber.

In addition, the dense plasma formed by the helicon wave power supply applicator allows plasma to be generated further away from the workpiece without lowering the plasma density and having no adverse effects. Thus, a sufficient amount of neutral or charged particle species may be delivered to the main chamber before recombination.

In addition, a power supply applicator capable of generating helicon waves efficiently couples power supply to produce a highly uniform plasma over a wide range of temperatures and power.
Can be If the plasma generated by the helicon wave in the magnetic field has uniformity, the plasma can flow into the main chamber and generate more uniform processing plasma.

To further enhance uniform processing plasma and seed density control, a main processing chamber power supply current applicator may be provided proximate to the main chamber. The main processing chamber power supply may use the processing gas supplied to the main chamber to generate a processing plasma in the main chamber. An auxiliary plasma may be introduced into the main chamber and added to the ignited processing gas such that the ignited processing gas and the auxiliary plasma form a processing plasma in the main chamber.

Accordingly, the auxiliary plasma may be formed mainly from neutral radicals or mainly from charged particles. Adjusting the auxiliary chamber parameters, such as power supply power, controls the density of neutral and charged particles in the auxiliary plasma. Thus, the auxiliary chamber may be a source of neutral radicals or a source of charged particles to the main processing chamber.

As described above, the density of the neutral and charged particle species of the auxiliary plasma is selected to produce the desired species density in the main chamber. Thus, the auxiliary plasma regulates the seed density in the main chamber. In addition, as described above, a filter is interposed between the auxiliary source chamber and the main chamber to further control the density of the auxiliary plasma species, thereby allowing for further adjustment and further control of the density of the processing plasma species. Become like

Therefore, according to the present invention, the control of the density of the processing plasma species can be performed separately from the overall density. One method provided by the present invention for separately controlling the overall density and seed density of the processing plasma is by applying power to the auxiliary chamber and the main processing chamber. The auxiliary plasma applied to the main chamber with the applied power supply thereby forms the processing plasma. Another way to separate the overall density from the main density is to apply power supply power to a first auxiliary chamber and a second auxiliary chamber to combine these plasmas in the main chamber to form a processing plasma. Done by Yet another way to separate the overall density from the main density is by applying power to the auxiliary chamber and filtering the auxiliary chamber plasma to form a process plasma in the main chamber. Yet another way to separate the overall density from the main density is to apply power to the auxiliary chamber and supply another source of neutrals to the main chamber, such as thermally dissociated species, to process the main chamber. Is to form a plasma.

In addition, by applying bias power to the workpiece, the present invention allows for separate control of ion energy, seed density and overall density of the processing plasma.

It should be noted that, in the present invention, the processing gas may be introduced into only the auxiliary chamber, both the auxiliary chamber and the processing chamber, or only into the processing chamber to process the workpiece. It should also be noted that during processing of the workpiece, power may be applied to both the main chamber and the auxiliary source chamber. Thus, the act of simultaneously generating and applying power to the auxiliary source chamber and the main processing chamber may be continuous or pulsatile, and, if desired, alternate between chambers. Is also good.

[Brief description of the drawings]

FIG. 1 is a schematic view of a plasma reactor combined with an auxiliary source chamber according to the present invention.

FIG. 2A is a partial cross-sectional side view of the auxiliary power chamber of FIG. 1 using a microwave power applicator.

FIG. 2B is a side cross-sectional view of the auxiliary power chamber of FIG. 1 using an induction coil power applicator.

2C is a side cross-sectional view of the auxiliary source chamber of FIG. 1 using a magnetically enhanced inductive power applicator.

2D is a side cross-sectional view of the auxiliary source chamber of FIG. 1 using a magnetically enhanced induction power applicator having a dome-shaped top.

2E is a side cross-sectional view of the auxiliary source chamber of FIG. 1 using a capacitive power applicator including a pair of facing internal electrodes.

FIG. 2F is a side view of the auxiliary source chamber of FIG. 1 using a capacitive power applicator that includes a pair of facing external electrodes.

FIG. 3 is a schematic diagram of a plasma reactor combined with a plurality of neutral particle source chambers according to the present invention.

FIG. 4 is a side cross-sectional view of a plasma reactor combining the auxiliary source chamber of FIG. 1 utilizing an inductively coupled main processing chamber and a magnetically enhanced inductively coupled auxiliary chamber.

5A is a side sectional view of the conduit recombination filter of FIG. 1. FIG.

FIG. 5B is a side cross-sectional view of the multiple conduit recombination filter of FIG. 5A.

6 is a side cross-sectional view of the plasma reactor of FIG. 4 utilizing the multiple conduit recombination filters of FIG.

FIG. 7A is a perspective view of a grounded grid type recombination filter of the present invention.

FIG. 7B is a perspective view of a biased grid-type recombination filter of the present invention.

FIG. 7C is a perspective view of a magnetic quadrupole type filter of the present invention.

FIG. 7D is a perspective view of a magnetic type filter of the present invention.

FIG. 8 is a side cross-sectional view of the plasma reactor of FIG. 1 utilizing a magnetically enhanced inductively coupled auxiliary source chamber and an inductively coupled main processing chamber and showing possible filter arrangements.

FIG. 9 is a side cross-sectional view of the plasma reactor of FIG. 3 utilizing a magnetically enhanced inductively coupled auxiliary source chamber and an inductively coupled main processing chamber.

FIG. 10 is a side cross-sectional view of the plasma reactor of FIG. 1 utilizing a magnetically enhanced inductively coupled auxiliary source chamber and an inductively coupled main processing chamber having a flat ceiling.

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), JP, KR (72) Inventor Corandenco, Arnold United States of America, San Francisco, California, San Francisco, Eucalyptus Drive 1747 (72) Inventor Shan, Hong, Ching United States of America, California, San Jose, Tumble Way 3630 (72) Inventor Lowenhard, Peter United States, California, San Jose, Rosswood Drive 1862 (72) Inventor Lee, Chi United States of America, California, Fremont, Solstice 746 (72) Inventor E. Jan United States of America, California, Campbell, Via Sarais 3862 (72) Inventor Chang, Cuyen United States of America, California, Milpitas, Rose Drive 230 (72) Inventor of Cue, Songlin United States of America, Dennis Street, Fremont, California 41641 (72) Inventor Chen, Arthur United States of America, California, Fremont, Bottega Court 744 (72) Inventor Sato, Arthur United States of America, California, San Jose, Eastas Drive 4733 (72) Inventor Grimbergen, Michael United States, California, Redwood City, Martinique Drive 767 (72) Inventor Mar, Diana United States of America, Saratoga, California , Quilt Court 19600 (72) Inventor Yamartino, John United States of America, Palo Alto, California 385 (72) Inventor Jan, Chun United States of America, California, Santa Clara, Monroe Street 2200 Number 1208 (72) Inventor Twarski, Wade United States, California, Sunnyvale, Charlay Avenue 860 F-term (reference) 5F004 AA03 AA05 BA04 BA20 BB18 BB28 BC08 CA02 DA00 DA04 DA25 DA26 DB03 DB07

Claims (35)

[Claims] 1. A plasma reactor, comprising: a) a processing chamber including a workpiece and capable of generating a processing plasma; b) an auxiliary chamber capable of generating an auxiliary plasma; A plasma reactor including the auxiliary chamber coupled to the processing chamber for introducing plasma generated in the chamber into the processing chamber to enable processing of a workpiece. 2. The plasma reactor of claim 1, further comprising a processing chamber power supply applicator and an auxiliary chamber power supply applicator. 3. The process chamber power supply applicator further includes a processing plasma generated in the processing chamber comprising neutral and charged particle species having a density and further comprising an auxiliary chamber power supply applicator. 3. The process chamber of claim 2, further comprising an auxiliary plasma generated in an auxiliary chamber, wherein the processing chamber power supply applicator and the auxiliary chamber power supply applicator enable adjustment of a seed density of the processing plasma. Plasma reactor. 4. The processing plasma has a total density and the processing chamber power supply applicator and the auxiliary chamber power supply applicator separate the processing plasma main power density from the processing plasma power density. The plasma reactor according to claim 3, wherein adjustment of the temperature is possible. 5. The plasma reactor according to claim 3, wherein said auxiliary plasma mainly contains charged particles. 6. The plasma reactor according to claim 3, wherein said auxiliary plasma mainly contains neutral particles. 7. The plasma reactor according to claim 1, further comprising a filter inserted between the auxiliary chamber and the processing chamber. 8. A processing chamber power supply applicator further comprising a processing plasma generated in the processing chamber comprising neutral and charged particle species having a density and further comprising an auxiliary chamber power supply applicator. The method of claim 7, further comprising an auxiliary plasma generated in the chamber, wherein the processing chamber power supply applicator, the auxiliary chamber power supply applicator, and the filter enable adjustment of a seed density of the processing plasma. The plasma reactor as described. 9. The plasma reactor according to claim 8, wherein said auxiliary plasma mainly comprises charged particles. 10. The plasma reactor according to claim 9, wherein said filter mainly passes neutral particle species from said auxiliary chamber to said processing chamber. 11. The plasma reactor according to claim 10, wherein the charged particle species of the auxiliary plasma are recombined by the filter to form neutral particle species, and then introduced into the processing chamber. 12. The plasma reactor according to claim 9, wherein said filter passes selected charged particles from said auxiliary chamber to said processing chamber. 13. The filter of claim 1, wherein the filter passes primarily charged particles having a selected charge-to-mass from the auxiliary chamber to the processing chamber.
3. The plasma reactor according to 2. 14. The auxiliary plasma according to claim 8, wherein the auxiliary plasma mainly comprises neutral particles.
3. The plasma reactor according to 1. 15. The plasma reactor according to claim 14, wherein the filter mainly passes neutral particles from the auxiliary chamber to the processing chamber. 16. The plasma reactor according to claim 14, wherein said filter mainly passes charged particles from said auxiliary chamber to said processing chamber. 17. The plasma reactor of claim 1, further comprising a processing chamber power supply power applicator capable of generating a processing plasma and controlling a total density of the processing plasma. 18. The plasma reactor of claim 17, wherein said processing chamber further comprises a bias power replicator capable of controlling ion energy at a workpiece. 19. The plasma reactor of claim 1, wherein said processing chamber further comprises a bias power replicator capable of controlling ion energy at a workpiece. 20. The plasma reactor of claim 19, wherein said bias power replicator further comprises one cathode and one anode. 21. The plasma reactor according to claim 1, wherein the auxiliary chamber further includes an auxiliary power applicator capable of generating a helicon wave in the auxiliary chamber. 22. The plasma reactor of claim 1, wherein said auxiliary chamber further comprises a magnetically enhanced inductively coupled power supply applicator. 23. The plasma reactor of claim 22, wherein said magnetically enhanced inductively coupled power supply applicator is capable of generating helicon waves. 24. The processing chamber of claim 2, further comprising an inductive antenna.
3. The plasma reactor according to 2. 25. The plasma reactor of claim 24, wherein said processing chamber further comprises a ceiling, and wherein said auxiliary chamber is coupled to a ceiling of said processing chamber. 26. The plasma reactor according to claim 25, wherein the inductive antenna is disposed above a ceiling of the processing chamber. 27. The plasma reactor according to claim 26, wherein a ceiling of the processing chamber has a dome shape. 28. The plasma reactor according to claim 26, wherein the ceiling of the processing chamber is flat. 29. The plasma reactor of claim 25, wherein said processing chamber further comprises a side wall, and wherein said inductive antenna is disposed adjacent to a side wall of said processing chamber. 30. The plasma reactor according to claim 29, wherein a ceiling of the processing chamber has a dome shape. 31. The plasma reactor according to claim 29, wherein a ceiling of the processing chamber is flat. 32. A method of processing a workpiece, comprising: a) generating an auxiliary plasma; b) filtering the auxiliary plasma; c) generating a main plasma; d) filtering the main plasma. Forming a processing plasma comprising a mixture of the selected auxiliary plasmas; and e) exposing the workpiece to the processing plasma. 33. The workpiece processing method according to claim 32, wherein the auxiliary plasma is generated so as to be mainly composed of neutral species. 34. The workpiece processing method according to claim 32, wherein the auxiliary plasma is generated so as to be mainly composed of charged particles. 35. The method of claim 32, wherein the auxiliary plasma filters to remove charged particles.