JP2012142332A - Method of manufacturing electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fill around a recess with a low-melting-point metal well by preventing aggregation of the low-melting-point metal being deposited at high temperature, and forming a barrier layer having sufficient barrier properties and wettability.SOLUTION: The method of manufacturing an electronic component includes a step for depositing a first barrier layer 404 composed of TiNx on an object 306 to be treated by plasma treatment by applying a first bias power to an electrode 301 which is in contact with the object 306 to be treated under a pressure of 4-20 Pa, a step for depositing a second barrier layer 405 composed of TiNx on the first barrier layer by plasma treatment by applying a second bias power, which imparts incident ion energy lower than that of the first bias power, to the electrode 301 under a pressure of 4-20 Pa, a step for depositing a third barrier layer 409 composed of Ti on the second barrier layer 405, and a step for filling above the third barrier layer 409 with a low-melting-point metal 406.

Description

  The present invention relates to a method of manufacturing an electronic component suitable for filling a recess on a surface of a dielectric layer of an integrated circuit with a low melting point metal.

  Along with the high integration of LSI (Large Scale Integration), contact holes such as contact holes for obtaining electrical connection between the substrate and wiring and vias for obtaining connection between multilayer wirings are also miniaturized, and the aspect ratio is 1 Is over.

  Such fine holes are filled with a conductive material and electrically connected. Generally, an Al-based alloy is used as a wiring material from the viewpoint of low resistance and workability. Here, the Al-based alloy is a concept including not only pure Al but also Al, such as Al-Si and Al-Cu, with a small amount of additive added. write.

  Conventionally, a technique called reflow has been used as a filling technique for facilitating filling of fine holes with a high aspect ratio. In reflow, first, a barrier layer (referred to as a barrier metal) is formed for the purpose of preventing diffusion of Al and Si. Usually, TiN (titanium nitride) or the like is used for this barrier layer. In the case of a contact hole, in order to form titanium silicide, which is a Ti compound that can realize a low-resistance contact, it is common to take a laminated structure in which Ti is formed as a lower layer.

  Next, Al is filled, but since reflow is performed at a high temperature of about 400 ° C., if the film is formed as it is on the barrier layer, the wettability between TiN and Al as the outermost layer of the barrier is poor, and the film is formed at a high temperature. Al aggregated into individual droplets. Therefore, burying becomes insufficient without maintaining continuity, and voids called voids 410 as shown in FIG. 10 are formed.

  In order to prevent this, it is necessary to form a continuous Al flow path on the barrier layer. This flow path is called a seed layer (seed layer), and an Al layer formed at 100 ° C. or lower is used. After securing the flow path, an Al film is formed at a high temperature of about 400 ° C., and the hole is filled with Al. The film formation of Al as the seed layer at a low temperature and the film formation of Al at a high temperature are generally performed by transferring the substrate into different chambers in which the temperature of the substrate holder is adjusted to a predetermined temperature.

  As a related technique, there is a means for embedding the connection hole by heating the substrate to a temperature of 300 ° C. or higher after forming an Al-based film by sputtering while cooling the semiconductor substrate having the connection hole at 0 ° C. or lower under vacuum. A semiconductor manufacturing apparatus has been proposed (see, for example, Patent Document 1).

  Moreover, since Al has a light mass among metal atoms, a disconnection failure due to electromigration is particularly problematic. In order to improve this electromigration resistance, it is known that strengthening the (111) orientation of Al is effective. As a technique for enhancing the orientation of Al, a method is proposed in which a (111) -oriented TiN film is formed on a (002) -oriented 100 nm or less Ti film, and Al is formed thereon. (For example, refer to Patent Document 2). Generally, by strengthening the crystal orientation of the barrier layer, the crystal orientation of Al is strengthened and the electromigration resistance is improved.

  This result indicates that Al grows in a direction perpendicular to the substrate according to the crystallinity of the underlying barrier layer. In other words, the stronger the crystallinity of the base, the more the growth direction is affected, which restricts the movement flowing along the opening.

JP-A-7-74177 JP-A-6-283532

  However, there are several problems with the above-described method. First, when the crystallinity of the underlayer is strong, Al is constrained by the underlayer, grows in the vertical direction of the substrate, and inhibits the movement of Al flowing into the opening.

  The second problem is the shape of the seed layer. The seed layer is formed in a cooled state in order to suppress aggregation. For this reason, there is no movement of particles due to migration in the covering shape of the seed layer, and an overhang shape 421 may be formed in the opening as shown in FIG.

These defects tend to become more prominent as the fine pores have a higher aspect ratio, and are considered to be the limitations of conventional techniques using reflow.
In other words, filling Al with fine holes having a high aspect ratio requires control of the base restraint force, that is, crystallinity, and improvement of the Al covering shape.

  The present invention relates to a method of manufacturing an electronic component, an electronic component, a plasma processing apparatus, a control program, and a recording medium that can form a barrier layer having sufficient barrier properties and wettability, and can fill a recess with a low-melting point metal. It is intended to provide.

  The configuration of the present invention made to achieve the above object is as follows.

  A barrier layer film-forming procedure for forming a barrier layer on the object to be treated, and a filling procedure for filling the recess of the object on which the barrier layer is formed with a low-melting point metal layer. The film forming procedure includes applying a first bias power to a bias electrode in contact with an object to be processed, forming a first layer containing TiNx (x is a positive number) by plasma processing, and forming the first layer on the electrode. A TiNy (y is a positive number) is applied on the first barrier layer by plasma treatment by applying a second bias power that gives an ion incident energy smaller than a bias power of 1 or without applying a bias power. And a procedure for forming a second layer including Ti, and a procedure for forming a third layer made of Ti between the second layer and the low-melting-point metal by plasma treatment.

  According to the present invention, it is possible to prevent agglomeration of a conductive metal film formed at a high temperature, to form a barrier layer having sufficient barrier properties and wettability, and to fill the concave portion with a conductive metal well.

It is a schematic sectional drawing which shows typically the plasma processing apparatus of this embodiment. It is the top view which looked at the magnet mechanism from the target electrode (1st electrode) side. It is the schematic which shows the multi-chamber system of this embodiment typically. It is the schematic which shows the procedure of the manufacturing method of the electronic component of this embodiment. It is explanatory drawing of the transport process of the sputtered particle of high pressure sputtering. It is explanatory drawing of resputtering. It is explanatory drawing of the particle transportation process of a low pressure sputtering and a high pressure sputtering, and an accompanying shape. It is explanatory drawing which shows the X-ray-diffraction pattern of a barrier layer. It is a SEM micrograph which shows the filling result in this embodiment. It is explanatory drawing which shows the void in the conventional recessed part (micropore). It is explanatory drawing which shows the surrounding state in low pressure sputtering.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiments.

[Plasma processing equipment]
First, the configuration of an embodiment of a plasma processing apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view schematically showing the plasma processing apparatus of the present embodiment.

  As shown in FIG. 1, the plasma processing apparatus 100 of this embodiment includes a container (chamber) 201 that partitions a processing space, and an upper electrode (discharge electrode) 1 and a lower electrode ( Bias electrode) 301.

  The chamber 201 is a hollow cylindrical container, and includes a substantially disc-shaped upper wall (ceiling wall) 202, a substantially cylindrical side wall 203, and a substantially disc-shaped bottom wall 204. Below the processing space defined in the chamber 201, a stage holder 302 is provided as a mounting table for holding a target object 306 such as a substrate or an electronic component.

  An exhaust port 205 is provided in the side wall of the chamber 201, and an exhaust pump 10 that evacuates the chamber 201 is connected to the exhaust port 205. Further, a gas introduction port 9 for introducing a processing gas such as argon into the processing space inside the chamber 201 is provided on the inner wall of the chamber 201, and this gas introduction port 9 is connected to a gas supply means (not shown). ing.

  Further, a pressure gauge 30 for measuring the pressure in the chamber 201 is provided on the side wall of the chamber 201. The pressure gauge 30 is formed by, for example, a diaphragm gauge or the like, and is connected to a pressure control mechanism 31 that controls the pressure in the chamber 201 based on the detection value of the pressure gauge 30.

  The upper electrode (discharge electrode) 1 includes an upper wall 202, a magnet mechanism 5, a target electrode (first electrode) 2, an insulator 4, and a shield 3.

  The magnet mechanism 5 is provided below the upper wall 202, and a target electrode 2 on which a target material is mounted is provided below the magnet mechanism 5. The main parts of the target electrode 2 are made of a nonmagnetic metal such as Al, austenitic stainless steel (SUS), or Cu. A target (not shown) necessary for forming a film on the substrate 306 can be installed on the reduced pressure side of the target electrode 2.

  The target electrode 2 is connected via a matching unit 101 to an upper electrode power source 102 such as a high frequency power source that supplies power to the target electrode 2 and a DC power source 103 that supplies DC voltage. The insulator 4 is for insulating the target electrode 2 and the side wall of the chamber 201 and holding the target electrode 2 in the chamber 201. Further, a shield 3 is provided below the insulator 4.

  Further, a pipe (not shown) is provided in the upper electrode 1 and the target electrode 2, and the upper electrode 1 and the target electrode 2 can be cooled by flowing cooling water through the pipe.

  The magnet mechanism 5 includes a magnet support plate 7, a plurality of magnet pieces 6 supported by the magnet support plate 7, and a magnetic field adjusting magnetic body 8 provided on the outermost peripheral side of the plurality of magnet pieces 6. Yes. The magnet mechanism 5 is configured to be rotatable about a central axis of the target material by a rotation mechanism (not shown).

  The plurality of magnet pieces 6 are disposed adjacent to each other so as to be parallel to the surface of the target electrode 2 above the target electrode 2. A point cusp magnetic field 11 is formed by adjacent magnet pieces 6.

  The magnetic body for magnetic field adjustment 8 is extended so that the magnet piece 6 located on the outer peripheral side partially overlaps on the target electrode 2 side. By adopting such a configuration, the magnetic field strength can be suppressed (controlled) in the gap between the target electrode 2 and the shield 3.

  The lower electrode (bias electrode) 301 includes a holder 302, a cooling / heating mechanism 12, a bottom wall 204, and a second electrode insulator 303.

  Inside the stage holder 302 on which the substrate 306 is placed, the cooling / heating mechanism 12 is provided.

  The second electrode insulator 303 is a device for electrically insulating and supporting the holder 302 and the bottom wall 204 of the chamber 201. The holder 302 is connected to a lower electrode power source 305 such as a high frequency power source for applying bias power to the object 306 via a matching unit 304. The lower electrode power source 305 is provided with a power control mechanism (not shown) that controls the bias power applied to the holder 302.

  Although not shown, the holder 302 is provided with an electrostatic adsorption device having a monopolar electrode, and this monopolar electrode is connected to a DC power source (not shown). The substrate 306 as a processing target is electrostatically attracted to the mounting surface of the holder 302 by this electrostatic adsorption device.

  Further, although not shown, the holder 302 has a plurality of gas jets for supplying a gas (for example, an inert gas such as Ar) for controlling the temperature to the back surface of the workpiece 306. A temperature measuring device for measuring the temperature of the object 306 is provided.

  Next, the magnet mechanism 5 will be described in more detail with reference to FIG. FIG. 2 is a plan view of the magnet mechanism as viewed from the target electrode (first electrode) side.

  As shown in FIG. 2, the disk-shaped magnet support 7 includes an annular magnetic field adjusting magnetic body 8 and a plurality of magnet pieces 6 arranged in the inner peripheral region of the magnetic field adjusting magnetic body 8. It is supported.

  Here, in FIG. 2, reference numeral 3 a indicates the inner diameter of the shield 3, and many small circles indicate the outer shape of each magnet piece 6. Each magnet piece 6 has the same shape and the same magnetic flux density. The letters N and S indicate the magnetic poles of the magnet piece 6 as viewed from the target electrode 2 side.

  Magnet pieces 6 are arranged vertically and horizontally (X-axis direction, Y-axis direction) in a grid pattern with substantially the same interval (range of 5 to 100 mm), and adjacent magnet pieces 6 have opposite polarities. have.

  On the other hand, in the quadrangle composed of any four magnet pieces 6 arranged along the X-axis direction and the Y-axis direction, the polarities of the magnet pieces 6 adjacent along the diagonal direction are the same. That is, a point cusp magnetic field 11 is formed by any four adjacent magnet pieces 6.

  The height of the magnet piece 6 is usually formed to be larger than 2 mm, and the cross-sectional shape thereof is a square or a circle. The diameter, height, and material of the magnet piece 6 can be appropriately set depending on the process application.

  In this embodiment, all the magnet pieces 6 assume the same magnet material so as to have an equivalent magnetic flux density.

  When high frequency power is supplied to the upper electrode 1 of the plasma processing apparatus 100, plasma is generated by a capacitively coupled mechanism, and this plasma is affected by the point cusp magnetic field 11.

  The magnetic body for magnetic field adjustment 8 is extended so that the magnet piece 6 located on the outer peripheral side partially overlaps on the target electrode 2 side. Thereby, the magnetic field intensity in the vicinity of the surface of the target electrode 2 can be suppressed (controlled). The magnetic field adjusting magnetic body 8 may be any material that can control the magnetic field strength in the gap between the target electrode 2 and the shield 3. For example, a material having high magnetic permeability such as SUS430 is preferable.

  In the magnet mechanism 5, the magnetic field can be adjusted by adjusting the area where the magnet piece 6 and the magnetic field adjusting magnetic body 8 overlap. That is, when the area where the magnet piece 6 and the magnetic field adjusting magnetic body 8 overlap is adjusted, the magnetic field necessary for sputtering the target electrode 2 is supplied to the outermost periphery of the target electrode 2. No magnetic field is supplied to the gap.

  In the present embodiment, the magnet pieces 6 are illustrated in the form of being arranged vertically and horizontally in a grid pattern with substantially the same interval therebetween, but the arrangement of the magnet pieces does not limit the effect of the present invention. Can be selected in a timely manner.

[Multi-chamber system]
In this embodiment, as will be described later, the barrier layer is formed, and the low-melting point metal is formed and filled, but it is preferable to perform them in separate film forming chambers. The system is suitable. FIG. 3 is a schematic view showing the multi-chamber system of the present embodiment.

As shown in FIG. 3, the multi-chamber system includes a transfer chamber 450 in the center, and a transfer mechanism (not shown) such as a handling robot is provided in the transfer chamber 450.
Three chambers are vacuum-connected to the transfer chamber 450 via gate valves (not shown). That is, the three chambers include a degas chamber 451 for degassing the object 306 to be processed, a barrier layer film formation chamber 452 for forming the first and second barrier layers 404 and 405, and a low melting point metal. It comprises a low melting point metal film forming chamber 453 for film formation and filling. Further, a load lock chamber 454 for connecting and removing the object 306 stored in the cassette 455 is connected to the transfer chamber 450 between the vacuum space and the atmosphere.

  In the present embodiment, the barrier layer film forming chamber 452 and the low melting point metal film forming chamber 453 are configured by the plasma processing apparatus 100. However, the present invention is not limited to this, and at least the barrier layer deposition chamber 452 only needs to be configured by the plasma processing apparatus 100.

[First Embodiment of Electronic Component Manufacturing Method, Electronic Component, Control Program, and Recording Medium]
Next, with reference to FIG. 1 to FIG. 4, an electronic component manufacturing method that is performed using the plasma processing apparatus 100 will be described. Note that the algorithm of the electronic component manufacturing method according to the present invention is stored as a control program in a storage unit of a control device (not shown) that controls the film forming process of the plasma processing apparatus 100, and at the time of starting the film forming process. Are read and executed by the CPU.

The control program is recorded on a recording medium readable by a computer (PC) and installed in a storage unit of the PC. As recording media, floppy (registered trademark) disks, magnetic recording media such as ZIP (registered trademark), magneto-optical recording media such as MO, CD-R, DVD-R, DVD + R, CD-R, DVD-RAM, DVD + RW (Registered trademark), optical disks such as PD, and the like. Also, flash memory systems such as CompactFlash (registered trademark), SmartMedia (registered trademark), Memory Stick (registered trademark), multimedia card, SD memory card, and the like can be given. Furthermore, removable hard disks, such as a micro drive (trademark) and Jaz (trademark), are mentioned.

  As described above, the electronic component manufacturing method of the present embodiment is roughly divided into a barrier layer deposition procedure, a low melting point metal deposition procedure, and a filling procedure, which are performed in separate deposition chambers. In this embodiment, the multi-chamber system shown in FIG. 3 is used.

  FIG. 4 is a schematic view showing the procedure of the electronic component manufacturing method of the present embodiment.

  As shown in FIG. 4A, in the object 306 of this embodiment, silicon dioxide 402 is laminated on a substrate 401, and a hole 408 is formed in the silicon dioxide 402. In the present embodiment, the substrate 401 having such a hole 408 is the object to be processed 306. Note that the hole 408 described below is an example of a recess (fine hole) in the present invention, and other examples include a trench (groove).

  In the electronic component manufacturing method of the present embodiment, first, the transfer mechanism of the transfer chamber 450 takes out the object 306 in the cassette 455 from the load lock chamber 454 and transfers it into the degas chamber 451 for degassing processing. After the degassing process is completed, the transfer mechanism takes out the object 306 from the degas chamber 451 and transfers it to the barrier layer deposition chamber 452. As described above, in this embodiment, the barrier layer film forming chamber 452 and the low melting point metal film forming chamber 453 are formed in the same configuration as the plasma processing apparatus 100.

  Next, the procedure for forming the barrier layer will be described.

  In this embodiment, Ti is used as the target material. First, argon gas is introduced into the chamber 201 from the gas inlet 9 of the barrier layer deposition chamber 452 at a predetermined flow rate. At the same time, the magnet mechanism 5 rotates at a predetermined rotation speed.

  At this time, the process control device (not shown) controls the pressure control mechanism 31 based on the detection value of the pressure gauge 30 and also controls the flow rate of the gas introduced into the chamber 201 from the gas insertion port 9. The pressure in the chamber 201 is maintained at a relatively high pressure.

  Specifically, the pressure in the chamber 201 is preferably set to 4 Pa or more and 20 Pa or less, and is set to 7 Pa in the present embodiment. The reason why the pressure in the chamber 201 is set to 4 Pa or more and 20 Pa or less is that when the pressure is less than 4 Pa, sputtered particles accumulate at the hole entrance as will be described later, and in the worst case, the hole entrance may be blocked. It is. On the other hand, when the pressure exceeds 20 Pa, the number of process gas molecules becomes too large, and there is a possibility that the problem that the sputtered particles cannot sufficiently reach the substrate 306 due to collision with the process gas molecules may occur.

  At this time, the workpiece 306 is electrostatically attracted by a voltage applied to an electrostatic attracting device (not shown). Further, the process controller (not shown) controls the gas ejected from the gas ejection port (not shown) based on the substrate temperature measuring instrument (not shown), so that the object 306 is maintained at a predetermined temperature. Is done.

Next, the upper electrode power supply 102 applies predetermined power and high-frequency power having a predetermined frequency to the target electrode 2. In the present embodiment, the power is 2500 W and the frequency is 60 MHz. The frequency is preferably 10 MHz or more and 100 MHz or less, and particularly preferably 20 MHz or more and 80 MHz or less.
The reason why the frequency of the high frequency power is set in this range is that the process gas particles can be easily and efficiently ionized.

  Next, as shown in FIG. 4B, a Ti layer 403 is formed in the hole 408. That is, when a voltage is applied to the target electrode 2 by the DC power source 103, argon ions are incident on the Ti target, and sputtering film formation is started. Then, after performing sputter deposition for a predetermined time, the power applied to the target electrode 2 from the upper electrode power source 102 and the DC power source 103 is stopped. The Ti layer 403 formed here is used for the purpose of reducing the contact resistance of the contact portion as described above.

  Next, as shown in FIG. 4C, the first barrier layer 404 and the second barrier layer 405 are sequentially formed on the Ti layer 403 by switching the bias power applied to the lower electrode 301. .

  First, the gas in the chamber 201 is switched to a mixed gas of argon gas and nitrogen gas (reactive gas). In this embodiment, the pressure in the chamber 201 after introducing the mixed gas is adjusted to 10 Pa. Reactive sputtering is started by applying power to the upper electrode power source 102 and the DC power source 103 in the same manner as the Ti layer 403. At that time, since it reacts with the introduced nitrogen gas, the target material titanium reaches the substrate as TiN (titanium nitride).

  At this time, the first bias power is applied to the lower electrode 301 by the power supply 305 for the lower electrode. In the present embodiment, the first bias power is 600 W. The bias power forms a sheath made of plasma on the lower electrode 301, accelerates sputtered particles and process gas particles partially ionized, and draws them into the substrate 401. The substrate 401 and the film in the film formation process are deposited by obtaining incident energy of colliding ions.

  Here, with reference to FIG. 5 to FIG. 7, the behavior of the sputtered particles in the barrier layer deposition procedure of the present embodiment will be described. FIG. 5 is an explanatory diagram of a process of transporting sputtered particles in high pressure sputtering. FIG. 6 is an explanatory diagram of resputtering. FIG. 7 is an explanatory diagram of the particle transport process and the associated shape of low-pressure sputtering and high-pressure sputtering.

  As shown in FIG. 5, in the present invention, film formation is performed at a higher pressure than in normal sputtering. Therefore, the sputtered particles 430 that have jumped out of the target 2a have a short mean free path, and gas flows while arriving at the substrate 401. Repeat collisions with particles. And the kinetic energy at the time of jumping out of the target 2a is lost, and it flies near the substrate. Particles flying near the substrate are accelerated in a direction perpendicular to the substrate 401 by the plasma sheath 431 generated by the bias voltage applied to the holder and drawn into the hole.

  In addition, as shown in FIG. 6, when the process gas ions drawn into the substrate 401 become more than a certain incident energy, the sputtered film attached to the substrate 401 is sputtered (resputtered) again. Since the process gas ions drawn into the substrate 401 are accelerated in the vertical direction of the substrate, the adhesion film at the bottom of the hole is re-sputtered and adheres to the side wall of the hole. Thereby, a side wall part with little amount of attachment is reinforced, and a favorable coverage shape can be obtained as a whole.

  Furthermore, as shown in FIGS. 7C and 7D, since it spreads in the container due to scattering by the collision of sputtered particles until the arrival of the substrate and is incident by sheath acceleration at the holder, the entire surface of the substrate is symmetrical. A good covering shape can be obtained. On the other hand, as shown in FIGS. 7A and 7B, in low-pressure sputtering, since scattering due to collision of sputtered particles does not occur before the arrival of the substrate, the coating shape is biased.

  Then, after film formation for a certain period of time, the bias power applied to the lower electrode 301 is switched to a second bias power smaller than the first bias power. In this embodiment, the output from the lower electrode power source 305 is set to 0 W, and only acceleration from the plasma potential is performed. After the film formation with the second bias voltage is performed for a certain time, the power applied to the target electrode 2 from the upper electrode power source 102 and the DC power source 103 is stopped.

  Here, the barrier layer obtained by the above procedure will be described. FIG. 8 is an explanatory diagram showing an X-ray diffraction pattern of the barrier layer.

  FIG. 8A shows an X-ray diffraction pattern when only the first barrier layer is formed. The first barrier layer is deposited as a film that receives excessive ion incident energy given by the first bias power (in this embodiment, bias power 600 W), breaks crystal growth, and does not have strong orientation. To do. On the other hand, when the film is formed with the second bias power (in this embodiment, the bias power is 0 W), since there is no excessive ion incident energy, the crystal orientation in which the close-packed surface of the crystal is parallel to the substrate is obtained. A strong layer is formed. This corresponds to (c) in FIG. 8, and a clear diffraction peak due to the TiN (111) plane can be confirmed.

In addition, the surface of the film obtained with the second bias power is a flat film in which the above-described columnar structures are densely arranged and the surface roughness is small. Although not shown, as a result of cross-sectional observation by SEM, a clear crystal structure was not confirmed in the film obtained with the first bias power.
On the other hand, the film formed with the second bias power was confirmed to have a fine columnar structure.

  FIG. 8B is a diffraction pattern in the case where the two layers are stacked, and the above-mentioned peaks are confirmed, and the crystal orientation of the second barrier layer is also suppressed as compared with FIG. 8C. . This is due to the influence of the first barrier layer having poor crystallinity. By controlling the [001] crystal orientation of the first barrier layer, the [001] crystal orientation of the second barrier layer is controlled. It is easily guessed that control is possible.

  Next, changes in the film quality of the barrier layer due to bias application will be described.

  TiN generally has a columnar crystal structure and exhibits crystal orientation in which the close-packed surface of the crystal is parallel to the substrate. Therefore, when forming the barrier layer, first, the energy of ion incidence by bias is increased to form the first barrier layer 404 having a broken crystal structure and weak crystal orientation. Thereafter, the second barrier layer 405 having strong crystal orientation is formed by lowering the energy of ion incidence.

  The purpose of weakening the crystal orientation of the first barrier layer 404 is to weaken the crystallinity of the barrier layer as a whole and to function as a seed layer for the second barrier layer 405 formed thereafter. As described above, the crystal growth often grows according to the underlying crystal structure / crystallinity, and the growth of the layer stacked thereon can be controlled by changing the structure of the seed layer.

The application of bias also affects the covering shape of the barrier layer to be formed. Etching by incident ions occurs particularly in the opening, and the deposited film thickness becomes thin, and in the worst case, the base is exposed. Therefore, it is effective that the second bias power suppresses excessive incident ion energy and secures a film thickness sufficient to have the barrier property of the opening.
Subsequently, the gas is switched to argon gas again, and a Ti layer 406 as a third barrier layer is formed in the hole 408 as shown in FIG. That is, when a voltage is applied to the target electrode 2 by the DC power source 103, argon ions are incident on the Ti target, and sputtering film formation is started. Then, after performing sputter deposition for a predetermined time, the power applied to the target electrode 2 from the upper electrode power source 102 and the DC power source 103 is stopped.

At this time, since the third barrier layer 406 grows in accordance with the crystallinity of the first and second barrier layers, which are the underlying layers, the thicknesses of the first and second barrier layers and the bias applied when the barrier layer is formed are applied. The film quality of the third barrier layer can be controlled by the power and the ratio.
In this way, by inserting the Ti layer, even when the barrier layer and the high-temperature low-melting-point metal layer 406 are in direct contact, aggregation of the low-melting-point metal layer 406 can be suppressed, and voids are generated more reliably. Can be prevented. If the Ti layer is too thin, the effect of inserting the Ti layer cannot be obtained, and if the Ti layer is too thick, an alloy layer of Ti and Al is formed. In many cases, this alloy layer has large grains, and due to its strong adhesion, the fluidity of the barrier layer and the Al interface is significantly reduced. Therefore, when a Ti layer is formed as the third barrier layer 409, the thickness is preferably 5 nm or more and 30 nm or less.

  Next, the filling procedure of the low melting point metal will be described.

  After film formation of the barrier layers 404 and 405 is completed, the transfer mechanism takes out the object 306 from the barrier layer film formation chamber 452 and transfers it to the low melting point metal film formation chamber 453 without exposing to the atmosphere. The filling of Al was performed using the plasma processing apparatus 100 as the low melting point metal film forming chamber 453 similarly to the barrier layer.

  In this embodiment, Al—Cu is used as the target material. Similarly to the barrier layer, argon gas is introduced from the gas inlet 9 and the magnet mechanism 5 is rotated.

  In this embodiment, the pressure in the chamber 201 is 5 Pa. The substrate temperature is heated to the extent necessary for Al flow. Specifically, the substrate is desirably heated to 300 ° C. or higher and regulated to 350 ° C. or higher and 450 ° C. or lower. In this embodiment, the substrate is heated to 420 ° C.

  When the substrate temperature is sufficiently saturated, the upper electrode power supply 102 then applies a predetermined power and a high frequency power having a predetermined frequency to the target electrode 2. In this embodiment, the power is 4000 W and the frequency is 60 MHz.

  Next, a voltage is applied to the target electrode 2 by the DC power source 103, whereby argon ions are incident on the aluminum target, and sputtering film formation is started. After the sputtered Al particles adhere to the substrate, the migration is promoted by the heat energy by heating and moves in the above-described barrier layer shape, and the low melting point metal layer 407 is placed in the hole 408 as shown in FIG. Filled.

  Then, after performing the sputter film formation for a predetermined time, the power applied to the target electrode 2 from the upper electrode high-frequency power source 102 and the DC power source 103 is stopped.

[Example]
FIG. 11 is a photomicrograph showing the cross-sectional observation result by SEM of the hole buried according to this embodiment. As shown in FIG. 11, it was confirmed that embedding was performed without forming a void in a hole of φ0.2 μm.
It should also be noted that the embedding of the hole pattern having a depth of 1.0 μm is completed with an Al film formation amount of only 200 nm. In FIG. 11, it can be observed that almost no aluminum remains on the substrate surface, and Al preferentially flows in the opening. This also shows that the control of the Al fluidity according to the present invention can sufficiently fill even a high aspect fine pattern.

  In addition, the effect of the present invention is clearly shown in that the seed layer that has been conventionally required for the reflow process is not formed in the above-described procedure. Even without using a seed layer, which has been conventionally required as a flow path layer, by controlling the crystal orientation of the barrier layer, it is possible to form a film of Al directly at a high temperature without forming a void. Al filling can be performed. In addition, the conventional Al film forming chamber for the seed layer and the Al film forming chamber at a high temperature were required, but the film can be formed in a single Al film forming chamber, thereby reducing the manufacturing cost. be able to.

  As mentioned above, although preferred embodiment of this invention was described, this is an illustration for description of this invention, and is not the meaning which limits the scope of the present invention only to the said embodiment. The present invention can be implemented in various modes different from the above-described embodiments without departing from the gist thereof.

  For example, in the above-described embodiment, the sputtering apparatus has been described as an example, but the present invention can also be applied to other plasma processing apparatuses and electronic component manufacturing methods using the same.

1 Upper electrode 2 Target electrode (first electrode)
DESCRIPTION OF SYMBOLS 3 Shield 3a Shield inner diameter 4 Insulator 5 Magnet mechanism 6 Magnet piece 7 Magnet support plate 8 Magnetic body for magnetic field adjustment 9 Gas inlet 10 Exhaust pump 11 Point cusp magnetic field 12 Cooling / heating mechanism 30 Pressure gauge 31 Pressure control mechanism (APC) )
DESCRIPTION OF SYMBOLS 100 Plasma processing apparatus 101 Matching device 102 Power supply for upper electrodes 103 DC power supply 201 Container (chamber)
202 Upper wall (ceiling wall)
203 Side wall 204 Bottom wall 205 Exhaust port 301 Lower electrode 302 Holder 303 Second electrode insulator 304 Matching device 305 Lower electrode power supply 306 Object 401 Substrate 402 Silicon dioxide 403 Ti layer 404 First barrier layer (TiN)
405 Second barrier layer (TiN)
406 Third barrier layer (Ti)
407 Low melting point metal layer 408 Hole 410 Void 420 Adhesion film 421 Overhang shape 430 Sputtered particles 431 Plasma sheath 450 Transfer chamber 451 Degas chamber 452 Barrier layer film formation chamber 453 Al film formation chamber 454 Load lock chamber 455 Cassette

Claims (8)

A barrier layer forming procedure for forming a barrier layer on the object to be processed, and a filling procedure for filling the recess of the object on which the barrier layer is formed with a low melting point metal layer,
The barrier layer deposition procedure is as follows:
Applying a first bias power to a bias electrode in contact with the object to be processed, forming a first layer containing TiNx (x is a positive number) by plasma processing, and applying the first bias power to the electrode A second layer containing TiNy (y is a positive number) is formed on the first barrier layer by plasma treatment with or without applying a second bias power that gives a smaller ion incident energy. A method for manufacturing an electronic component, comprising: a step of forming a film; and a step of forming a third layer made of Ti between the second layer and the low melting point metal by plasma treatment.   The method of manufacturing an electronic component according to claim 2, wherein the third layer is formed to a thickness of 5 nm to 30 nm.   The method for manufacturing an electronic component according to claim 1, wherein the second layer has [001] crystal orientation stronger than that of the first layer.   The method of manufacturing an electronic component according to claim 1, wherein the first and second layers are formed by reactive sputtering using a reactive gas.   6. The method of manufacturing an electronic component according to claim 5, wherein the reactive gas is nitrogen.   The method for manufacturing an electronic component according to claim 1, wherein the target material for forming the barrier layer is Ti.   2. The method of manufacturing an electronic component according to claim 1, wherein the low melting point metal is Al or an Al-based alloy containing Al.   2. The method of manufacturing an electronic component according to claim 1, wherein the filling step is performed at 300 ° C. or more and 500 ° C. or less directly without sandwiching a low-temperature seed layer on the barrier layer.