JP5283103B2 - Target holding device and target holding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the propagation of heat to a target and prevent the elution of a material from a target holder to the target. <P>SOLUTION: The target holder 1 is provided with a target holding part 2 for holding the target 12 to be a target sample for a laser beam in laser ablation and a holder supporting part 3 connected to the target holding part 2 and rotated or rectilinearly moved by a rotating and moving mechanism, wherein the target holding part 2 is provided with a recessed part 2a for housing the target 12 and a first hollow part for housing the holder supporting part, and the holder supporting part 3 is provided with a second hollow part 3a formed therein and a cooling mechanism for circulating a coolant 4 to the second hollow part 3a to cool the target 12. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a target holding device and a target holding method for holding a target when a laser beam is irradiated to a target as a target sample, and in particular, when a high energy laser beam is irradiated to a target. The present invention relates to a target holding device and a target holding method that can suppress an increase in temperature of the target.

  As a conventional target holding apparatus described above, there is a laser ablation film forming method described in Patent Document 1. This method aims to suppress the generation of fine particles in the formed film by removing the hardware restrictions on the fine particles or fine particles contained in the target in the laser ablation film formation process. . In this step, the target is heated before laser irradiation, the above-mentioned fine particles or the generation source of the fine particles is removed, and then the substrate is cooled to a predetermined temperature and then laser irradiation is performed. The target is heated by bringing a heat-generating lamp close to the target.

  Moreover, in the rotating anode type X-ray tube device and the manufacturing method thereof described in Patent Document 2, heat radiation is achieved by a combination of heat conduction with an insulating material and liquid cooling. That is, it has a mechanism for rotating the target and is provided with a cooling mechanism, but the object of cooling is a rotating mechanism part, and the cooling mechanism is formed on a fixed body that supports a rotating body including the target with a bearing. Therefore, the target is indirectly cooled, and it is difficult to obtain a desired cooling effect.

Moreover, in the water atmosphere laser ablation method and apparatus described in Patent Document 3, the target is directly cooled by a cooling means containing liquid. However, the purpose of the cooling is to target a volatile organic substance, and the target is solidified using liquid nitrogen.
JP 2002-020859 A JP 2000-353485 A JP 2005-272898 A

  However, the cooling means in the apparatus described in Patent Document 1 described above is based on indirect heat conduction of the target support base, and the heat release is not performed strongly in order to increase the superheating efficiency. The thermal resistance is increased and does not inhibit the target and the surrounding area from becoming high temperature. Also in Patent Document 2, the object to be cooled is not the target but the rotating mechanism part, The cooling effect was indirect, and the high temperature could not be sufficiently suppressed. Further, in Patent Document 3, the target is directly cooled using liquid cooling that efficiently causes heat to flow out to the cooling means. The countermeasure to the high temperature of the target and the holding device and the introduction of the target rotation mechanism are not considered, and it is difficult to apply to the intended use here.

Therefore, in the above prior art, in the target holding device of the type that moves the beam irradiation position by rotating the target in response to the beam irradiation, the heat generated by the beam irradiation is only dissipated mainly by the heat conduction in the solid. In the example where the cooling capacity is insufficient and the heat is efficiently dissipated by liquid cooling, the target cannot be rotated to distribute the irradiation energy on the target. Therefore, heat accumulates in the target and the target holder with respect to the high-energy laser beam, and the deterioration of the target holder is promoted by the heat, and the impurities of the target holder deposited on the surface layer due to overheating migrate to the target by surface diffusion. However, there is a problem that the vapor is vaporized at the same time as the target and the purity of the vapor is significantly reduced. In addition, when the target cannot be rotated, even if heat can be released efficiently by liquid cooling, there is a problem in that the local melting region of the target is overheated due to local concentration of irradiation beam energy, and splashing of the melt occurs. It was.

  The present invention has been made in view of the above-described circumstances. In order to enable laser ablation with a high-energy laser beam, the target is prevented from being heated in a compact shape while rotating the target at a high speed. Thus, the target and the target holding device can be operated stably for a long time, and the purity of the material vapor generated by laser ablation is increased by preventing the elution of impurity material from the target holder to the target. An object of the present invention is to provide a target holding device and a target holding method.

In order to solve the above problems, the target holding device according to the first embodiment of the present invention is
Target to be a target sample for laser ablation, fixing means for fixing the target, rotating means connected to the fixing means and rotating the target together with the fixing means, and cooling for cooling the target together with the fixing means Means,
The target is rotated by the rotating means, and the target surface is prevented from being heated by cooling the target by the cooling means.

  By rotating the target, the energy applied to the target surface by laser beam irradiation is dispersed over a wide area of the target surface to prevent local overheating, and at the same time, the target passes from the wide area to the fixing means. Since a heat dissipation path in the solid is formed, the thermal resistance is reduced. This effect is further enhanced by increasing the target surface irradiation laser beam diameter. Furthermore, it becomes possible to efficiently remove a large amount of heat by having a heat release means for directly cooling the amount of heat reaching the rotating fixing means. Therefore, high-energy laser irradiation is possible, and a large amount of vapor can be generated by laser irradiation.

Further, the target holding device according to the second aspect relates to the target holding device according to the first aspect, wherein the inside of the fixing means is hollowed to the vicinity of the target, and the cooling means is formed in a cavity portion of the fixing means. The fixing means and the target are cooled by circulating or refluxing a cooling liquid.
In this configuration, the heat conducted from the target in the vicinity of the target inside the rotating fixing means is transferred to the liquid having a large heat capacity, and this heat is carried out by the flow of the liquid, and is generated at the target. The amount of heat can be released directly and most efficiently.

  In the case where the fixing means is rotationally driven from the outside different from the space atmosphere for performing the laser ablation, the fixed container forming the space for performing the laser ablation and the rotational driving portion or the fixed means for rotating by being driven. It is necessary to hermetically seal at the contact portion between them, and this can be realized by means such as magnetic sealing. Further, in the flow path for circulating or refluxing the liquid, the contact portion between the rotating portion included in the fixing means and the non-rotating portion included in the external liquid supply or discharge means is provided by means such as a bearing seal. Applicable.

Moreover, the target holding device according to the third aspect relates to the target holding device according to the first aspect, wherein the fixing means includes a fastener for fixing at a position of a rotation center axis of the target.
Fixing the target to the fixing means with a fastener means that the target does not move out of the fixing position even if the target fixing surface is not horizontal and has a free inclination. For example, the irradiation surface of the target is vertical. It is also possible to irradiate a laser beam from the side and blow the target material vapor in the horizontal direction. The fastener can be fastened at the position of the rotation center axis of the target because the laser irradiation position is deviated from the rotation axis of the target.

Moreover, the target holding device according to the fourth aspect relates to the target holding device according to the third aspect, wherein the tip of the fastener remains inside the target without protruding to the surface layer of the target. And
The fact that the tip of the fastener is sunk from the surface of the target means that the tip of the fastener is far from the irradiation position of the laser beam, and the tip of the fastener is hardly affected by the heat of the laser beam irradiation. Even if the fastener deposits impurities at a high temperature, the possibility of reaching the beam irradiation position through the surface is reduced.

  Further, the target holding device according to the fifth aspect relates to the target holding device according to the first aspect, and the inert gas shock wave induced by the target material vapor generated by laser ablation in the inert gas atmosphere container is generated on the container wall. The material vapor is reflected and confined in a specific region, and is attached to a cluster generation device that combines material atoms or molecules constituting the material vapor to generate a cluster.

  In order for the cluster generation apparatus to form a cluster film applicable to production, it is required that the generation amount of clusters per time is sufficiently large. For this purpose, ablation with a high energy laser beam is required. In addition, a small target fixing means that matches the dimensions of the container for laser ablation is required. By mounting the target holding device of aspect 1, powerful heat release is possible, and the above-described conditions can be satisfied.

Further, the target holding device according to the sixth aspect relates to the target holding device according to the first aspect, wherein the target fixing means includes a target support portion that closely contacts and supports the target, the target support portion and the fastener. However, it is characterized by being comprised with the material whose heat conductivity is 80 W / mK or more.
This is a condition for lowering the thermal resistance between the heat generating part of the target and the cooling means, and is a condition that can cope with irradiation of a high energy laser beam of 300 mJ or more.

Moreover, the target holding device according to the seventh aspect relates to the target holding device according to the first aspect, wherein the target fixing means includes a target support portion that closely contacts and supports the target, the target support portion and the fastener. However, it is characterized in that it is made of a material whose components other than the main component are 1 ppm or less.
In particular, when a film generated by laser ablation is applied to a semiconductor device, it is necessary to avoid contamination of the generated film with impurities. Since the target supporting part and the fastener are at high temperatures, it is the claim of the form 7 that the contained impurities are precipitated and the impurities are not mixed into the target material vapor generated by laser ablation.

Further, the target holding device according to the eighth aspect relates to the target holding device according to the first aspect, wherein the target fixing means includes a target support portion that closely contacts and supports the target, the target support portion and the fastener. However, it is characterized by being comprised from the material whose maximum temperature which can be used is more than melting | fusing point of the material of this target.
Moreover, the target holding method according to the ninth aspect is
A fixing step for fixing a target to be a target sample for laser ablation;
A rotating step of rotating the target;
A cooling step for cooling the target;
The target is rotated by the rotating step, and the target surface is prevented from being heated by cooling the target by the cooling step.

  The laser ablation apparatus according to the tenth aspect is a laser ablation utilization apparatus such as a laser ablation cluster beam apparatus or a laser ablation CVD apparatus including the target holding apparatuses according to the first to eighth aspects. Replacing the above target holding device with a conventional target holding device can significantly increase the allowable energy value in laser ablation due to high thermal conductivity and heat rejection effect, and can achieve uniform wear due to laser irradiation of the target by high-speed rotation Thus, it is possible to realize an apparatus configuration that suppresses the mixing of impurities during laser ablation, can easily attach and detach the target, and enables laser ablation in a compact space.

Further, the target holding method according to the eleventh aspect relates to the target holding method according to the ninth aspect, wherein the cooling step cools the target by circulating or refluxing a cooling liquid in the vicinity of the target. It is characterized by.
Moreover, the target holding method according to the twelfth aspect relates to the target holding method according to the ninth aspect, wherein the fixing step fixes the target at a position of the rotation center axis of the target using a fastener.

Moreover, the target holding method according to the thirteenth aspect relates to the target holding method according to the eleventh aspect, wherein the tip of the fastener remains inside the target without protruding from the surface layer of the target. And
Further, the target holding method described in the form 14 relates to the target holding method described in the form 9, and the inert gas shock wave induced by the target material vapor generated by laser ablation in the inert gas atmosphere container is caused on the container wall. The material vapor is reflected and confined in a specific region, and this is performed in a cluster generation apparatus in which material atoms or molecules constituting the material vapor are combined to generate a cluster.

Further, the target holding method described in the form 15 relates to the target holding method described in the form 9, and the fixing step fixes the target with a material having a thermal conductivity of 80 W / mK or more.
Further, the target holding method according to aspect 16 relates to the target holding method according to aspect 9, wherein the fixing step fixes the target with a material having a component other than the main component of 1 ppm or less. To do.
Further, the target holding method according to the form 17 relates to the target holding method according to the form 9, and the fixing step fixes the target with a material whose maximum usable temperature is equal to or higher than a melting point of the target material. It is characterized by doing.

  The configuration of the present invention is outlined above. In the laser ablation apparatus, the present invention provides a liquid circulation type in a target holding device having a function of rotating a target at high speed and moving an irradiation position of a high energy laser beam at high speed. A technique for providing a mechanism for directly cooling by cooling and realizing a holding device in a compact manner is provided. At that time, silicon carbide is used as an example on the condition that the melting point of the target holding part (target holder) is higher than that of the target material, the thermal conductivity is 80 W / mK or more, and the impurity is 1 ppm or less. ing. As for the structure, the distance along the target surface from the laser irradiation position on the target surface to the target holder is sufficiently separated, and the target is fixed with a fastener from the inside of the target toward the support base at the position of the rotation axis. It is said.

  As described above, according to the target holding device of the present invention, the amount of heat generated by the laser beam is effectively removed by a combination of a liquid medium having a high heat capacity and a high heat conductive material, so that a strong laser beam in a small space. This makes it possible to generate a large amount of material vapor. At the same time, impurities contained in the target holder (target holder) are prevented from diffusing into the laser beam irradiation surface and mixed into the material vapor, and further, the target is fixed with a fastener, so that the target installation surface can be It is also possible to stand vertically.

In addition, as an application example of the present invention, if it is attached to a cluster generation container, it is possible to form a high-purity cluster film at a high speed, and for example, it can be applied to a state-of-the-art silicon LSI that is entering the nano area of the cluster film Conceivable. That is, according to this technology, the generation of the film formation speed for forming the cluster film on the large area substrate is eliminated by eliminating the occurrence of the material purity required for application to the silicon device in the target support device. It is possible to increase the amount of material vapor required for the production.
In particular, the present invention efficiently realizes laser ablation using a high energy laser beam in a narrow space, and enables use in a production site such as application of nanoelectronics by using it in a cluster film forming apparatus. .

Hereinafter, a target holding device according to an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a schematic view showing a configuration of the entire cluster generation container to which the target holding device according to the first embodiment of the present invention is applied.
The cluster generation container 15 is for generating a cluster group 16 by disposing a target 12 serving as a cluster raw material and irradiating the target 12 with a laser beam L while introducing an inert gas. The cluster generation container includes a target holding device 1 for holding the target 12, an incident window 13 that is opened for introducing the laser beam L, and an outflow window 17 for flowing out of the cluster group 16.

  In the above configuration, the material vapor of the target 12 irradiated with the laser beam L generates a shock wave 14 of an inert gas, and the shock wave 14 is reflected by the inner wall of the cluster generation container 15 to confine the material vapor in the specific region B. A cluster group 16 of the material is generated by collision of vapor atoms or molecules, and the cluster group 16 is formed from an outflow window 17 provided on the wall of the cluster generation container 15 on a straight extension line connecting the target 12 and the specific region B. The cluster group 16 is sprinkled on the substrate 19 via the skimmer 18 disposed outside the cluster generation container 15 to generate the cluster film 20.

As shown in the figure, in a target generation container 15 as an example to which the target holding device of the present invention is applied, when the target 12 is irradiated with a high-energy laser beam 13, The surface is heated to several thousand degrees, and the material atoms in the irradiated region are instantaneously vaporized and ejected, and part of the heat diffuses to other regions in the irradiated region, and not only the target 12 but also the target. The target holding device 1 holding 12 is also overheated. The target holding device 1 includes a target holding part (target holder) 2 and a holder support part 3, and the target holding part 2 and the holder support part 3 are also overheated. Due to such thermal diffusion, heat is also diffused to other areas of the irradiation area A of the target 12. In principle, this heat does not heat the target 12 to the melting point or higher, and does not contribute to the generation of vapor by the target 12. However, instead of the heat transferred to the target holder 2 by this thermal diffusion, the deterioration of the material of the target holder 2 is promoted, and the impurities of the target holder 2 deposited on the surface layer of the target holder 2 are diffused to the target 12 by the surface diffusion. And the target 12 is vaporized at the same time as it is vaporized to significantly reduce the purity of the target 12 vapor. Excess heat that does not contribute is preferably exhausted by a cooling mechanism such as water cooling.

FIG. 2 is a cross-sectional view showing the configuration of the target holding device according to the first embodiment of the present invention.
The target holding device 1 according to the present embodiment includes a target holder 2, a holder support portion 3, and a cooling medium 4. That is, this embodiment is an example in which the cooling mechanism is provided inside the target holder 2, that is, inside the holder support portion 3. In addition, the target holder 2 and the holder support part 3 can use what was integrated as a fixing means.

  The target holder 2 is formed of a material having high thermal conductivity and high heat damage resistance in order to fix the disk-shaped target 12, and for receiving the recess 2 a for storing the target 12 and the holder support 3. The first cavity 2b. Further, when the target 12 is accommodated in the recess 2a, the target 12 is fixed at a predetermined position on the side surface of the target 12 using a screw 2c or the like.

The holder support portion 3 is formed in a cylindrical shape, holds the target holder 2, and rotates or linearly moves the target 12 in order to increase the irradiation area when the target 12 is irradiated with the laser beam L. It has a drive mechanism. Further, a part thereof is accommodated and fixed in a first cavity 2 b provided in the target holder 2, and a second cavity 3 a is provided inside the holder support part 3 to form a cavity.
The cooling medium 4 is filled in the second cavity 3 a formed inside the holder support 3, and cooling water is used in this embodiment. Moreover, although not shown in figure, the cooling device for circulating this cooling water is provided.

With the above-described configuration, water having a temperature of about 20 ° C. circulates and flows through the second cavity 3 a of the holder support 3 to cool the target 12 through the holder support 3 and the target holder 2.
When the material of the target 12 is silicon, for example, the material of the target holder 2 may be a high melting point transition metal such as molybdenum (Mo), tantalum (Ta), platinum (Pt).

  In consideration of the utilization efficiency of the rotating target 12, the shape of the target holder 2 is desirably a disk shape, and in the case of a cluster beam apparatus, the laser beam irradiation surface is arranged in the vertical direction. In that case, if a high melting point transition metal is used for the target holder 2, the target 12 can also be fixed with the screw 2c as described above. In any case, the setting of the target is performed so as to follow the operation of the holder support portion 3 that is rotationally driven or linearly driven. Thus, by using a refractory metal as the material of the target holder 2, various fixing methods such as fixing screw processing of the target 12 and integral processing in consideration of thermal conductivity become possible. Further, as shown in FIG. 2B, the installation position of the target holder 2 is set so that the laser beam irradiation area A ′ comes to a position X ′ shifted by d from the rotation center X of the target 2. preferable. That is, the center of the irradiation area A at the center of rotation and the center of the preferable irradiation area are separated by a distance d.

As described above, as the material of the target holder 2, a high melting point transition metal such as molybdenum (Mo), tantalum (Ta), or platinum (Pt) is used in consideration of thermal conductivity and heat damage resistance. Although it is preferable, as a problem at that time, it is difficult to obtain a highly pure material.
In addition, in order to achieve a design that secures the thermal conductivity necessary for removing the excess heat generated in the target 12 by laser irradiation, the shape of the portion where the target holder is in contact with the target 12 has a cross-sectional area of the heat release channel. A wide and short shape of the heat release flow path is desirable, but in this embodiment, the tip of the target holder 2 that wraps the side surface of the target 12 is for fixing the target 12 on the side surface, and the thickness is compared. It has a thin cylindrical shape, and this shape hinders heat conduction from the side surface of surplus heat generated in the target 12, and the cylindrical tip portion of the target holder 2 is locally hotter than other parts of the target holder 2. It is considered that impurities of the molybdenum material are deposited on the surface layer. This deposited impurity diffuses into the target 12, and when it reaches the laser irradiation surface, it is mixed into the target material vapor and mixed into the generated cluster, so pay attention to the temperature control of the cylindrical tip portion of the target holder 2. There is a need.

[Second Embodiment]
FIG. 3 is a cross-sectional view (a) and a front view (b) showing the configuration of the target holding device according to the second embodiment of the present invention.
This embodiment is different from the first embodiment described above in the shape of the target holder, and therefore the method for holding the target 12 is different. That is, the target holding device 10 according to the present embodiment includes the holder support portion 3 and the cooling medium 4 as in the first embodiment described above, but the target holder 5 supports the target 12. Target support part 5d, a target fixing pin 5c provided in the target support part 5d, and a hollow holder joint 5e serving as a joint with the holder support part 3. The target support portion 5d has a concave portion 5a shallower than the concave portion 2a in the first embodiment described above, and the target fixing pin 5c fixes the target 12 by being inserted into the disc-shaped rotation center of the target 12. Can do. In the first embodiment described above, the target 12 is fixed on the side surface of the target 12 with a screw or the like. However, in this embodiment, the method is changed to a method of fixing the sample at the center of rotation of the front surface of the disk-shaped target 12. ing. With this configuration, the target 12 is fixed closer to the laser beam irradiation position. Therefore, although the risk of thermal damage to the fixing pin 5c for fixing the target 12 increases, as a method for overcoming this problem, a target for fixing the target 12 from the surface of the target 12 to a depth corresponding to the diameter of the fixing pin 5c. The target 12 is fixed in a shape in which the fixing pin 5c is embedded in the target 12 without protruding from the surface. Thereby, the distance from the irradiation position of the laser beam to the fixing pin 5c is further increased, and thermal damage due to the temperature of the fixing pin 5c hardly occurs.

In the present embodiment, high-purity silicon carbide is also used for the target fixing pin 5c in consideration of thermal conductivity, maximum operating temperature, and purity. The target fixing pin 5c was used in a state in which the temperature was maintained within the melting point of the silicon target and no thermal damage occurred at a maximum operating temperature of 1700 ° C. or lower.
Further, in consideration of the inferior workability of the silicon carbide (SiC) material, the shape of the target holder 5 needs to be designed in a simple structure, but here, a sufficiently large contact area with the rotary linear drive mechanism head Sufficient heat conduction from the target holder 5 to the cooling device was ensured through the oxygen-free copper-like holder joint 5e.

  As described above, in the present embodiment, the shape of the target holder 5 is such that the concave portion 5a at the tip portion of the target holder 5 in contact with the side surface of the target 12 is shortened to 1/5 of the thickness of the target disk, and thermal conductivity does not decrease. Thus, the support method of the target 12 is improved. As described above, since the support portion 5d of the target 12 is shortened, the contact portion between the target holder 5 and the target 12 becomes far from the laser beam irradiation position, and the thermal conductivity is maintained and the target holder 5 is prevented from being thermally deteriorated. have.

[Third Embodiment]
FIG. 4 is an external view showing a configuration of a target holding device according to the third embodiment of the present invention.
This target holding device is an example in which a molybdenum target holder 100 made of molybdenum is used as the target holder 2 according to the first embodiment.
In the experiment using the molybdenum target holder 100, the target 12 is a disk-shaped polysilicon (impurity component 0.01 ppm or less) having a diameter of 20 mm and a thickness of 5 mm. The YAG pulsed laser beam with a wavelength of 532 nm was irradiated with energy of 800 mJ by fixing with a screw 2c from the outside through the inner side surface of the tip of 100. The tip of the molybdenum target holder 100 has a recess 2 a having a length about half the length of the side of the target 12 in contact with the target 12 and a holder support 3 for receiving the target 12. 1 cavity (see 2b in FIG. 2). In the above configuration, when the laser beam 13 is irradiated, impurities contained in the molybdenum material diffuse into the surface layer of the molybdenum target holder 100 and are evaporated together with silicon as the target material at the evaporation point of the target 12. There is a problem in that the purity of the vapor of the target 12 is lowered.

Therefore, as a method for overcoming the technical problem related to the decrease in the purity of the steam of the target 12, the material of the target holder was selected in consideration of thermal conductivity, heat damage resistance, and purity. I paid attention to.
FIG. 5 is a table showing physical characteristics of materials used for the target holder according to the third embodiment of the present invention. This table is generally a table comparing the properties and purity of available high-purity ceramics with refractory transition metals.

As shown in the figure, refractory transition metals and ceramics are conceivable as materials for the target holder used in the third embodiment of the present invention. Each material is described below.
First, examples of the high melting point transition metal include molybdenum (Mo), tantalum (Ta), and platinum (Pt). Examples of the ceramic include SiC (Pure Beta-S), SiC + m-Si (Pure Beta-R), AlN (Shapal = M), and Al ₂ O ₃ (alumina). For refractory metals, the maximum operating temperature [° C], thermal conductivity [W / mK], purity, and workability are compared. Ceramics have the highest operating temperature, Vickers hardness, thermal conductivity, and dielectric constant (partial). , Purity and processability were compared.

As a result, the maximum use temperature is Ta = 2990, Mo = 2610, AlN = 1900, Pt = 1770, SiC = 1700, Al ₂ O ₃ = 1600, SiC + m-Si = 1400. >Mo> AlN (Shapal-M)>Pt> SiC (Pure Beta-S)> Al ₂ O ₃ > SiC + m-Si (Pure Beta-S).

Further, the Vickers hardness Hv of the ceramic is SiC (Pure Beta-S) = 2200, SiC + m-Si (Pure Beta-S) = 1500, AlN (Shapal-M) = 390, Al ₂ O ₃ = 1530, and SiC. (Pure Beta-S)>2200>SiC> m-Si (Pure Beta-S)> 15 = 1500, AlN (Shapal-M) =. The thermal conductivity [W / mK] is Mo = 138, Ta = 57.5, Pt = 71.6, SiC = 230, SiC + m-Si = 180, AlN = 90, Al ₂ O ₃ = 38, dielectric The rate is AlN = 7.1, Al ₂ O ₃ = 10, the purity (ppm) is Au100, Pb10, Mg2, Fe5, Ni3, Ir10, Pd6, Cu5, Ag5, Rh10 in Pt, and in SiC Are B0.02, Na <0.01, Al0.08, K <0.01, Ti0, 02, Cr0.02, Mg0.02, Fe0.05Co <0.01, Ni <0.01, Cu0. 04, Zn0.01, W <0.01, and in SiC + m-Si (Pure Beta-S), B0.02, Na <0.005, Al0.05, K <0.01, Ti0.01, Cr0.02, Mg0. 1, Fe0.005Co <0.005, Ni <0.005, Cu <0.005, Zn <0.01, W <0.005. In AlN, Ca450, Cr60, Mg15, Ni <5, Fe20 and Si15 were obtained. As for workability, as for workability, Mo, Ta
, Pt, and AlN were machinable (machined), and SiC, SiC + m-Si, and Al ₂ O ₃ = 38 were molded.

As a result, with regard to the maximum operating temperature, aluminum nitride is superior in high-purity ceramics, but the thermal conductivity of silicon carbide (SiC) far exceeds the thermoelectric properties of refractory metals and is compared with all metals. Even so, it was found that the thermal conductivity was the second highest after silver (407 W / mK) and copper (381 W / mK). In terms of purity, it was relatively easy to obtain silicon carbide (SiC) as a high-purity material, and it was concluded that silicon carbide was the most excellent material used for the target holder.
In a silicon carbide target holder using silicon carbide (SiC), a design that does not impair the excellent thermal conductivity of silicon carbide (SiC) is particularly important. An example of a target holder using high purity silicon carbide (SiC pure Beta-S) is also conceivable.

[Fourth Embodiment]
FIG. 6 shows a rotation drive system as a rotating means for rotating the target and the target fixing means of the target holding device according to the fourth embodiment of the present invention, and cooling as a cooling means for cooling the target and the target fixing means. The structural example of a medium circulation system is shown typically.
The rotation of the rotation mechanism head composed of the target support portion 5d, the holder joint 5e, and the holder support portion 3 is transmitted from the pulley connected to the shaft of the motor 21 to the pulley of the rotation mechanism head via the belt 22, and further cylindrical. It is transmitted to the holder support 3 via the shaft 23.

  The target 12 fixed to the target support portion 5d at the tip of the rotating mechanism head is inside the cluster generation container 15 where laser ablation is performed, and the container 15 is further surrounded by a vacuum container 33. An inert gas atmosphere is supplied to the inside of the container 15, and a small amount of the inert gas flows out from the narrow gap around the rotary drive head into the vacuum container 33. The space 26 surrounding the rotating mechanism head is kept in a vacuum by powerful exhaust from the window 34.

Therefore, the magnetic seal 25 is disposed around the outer periphery of the rotating structure between the rotating mechanism head and the magnetic seal box 24, and the space between the external air and the internal vacuum space 26 is shut off to maintain airtightness.
Circulation of the cooling medium (herein described as water) 4 is performed by allowing cooling water to flow from the cooling water inflow pipe 27 provided inside the holder support 3 into the cavity in the holder support.

  The cooling water inflow pipe 27 is connected to the flexible pipe 28 and supplied with water cooled in the thermostatic bath 30. The cooling water that has absorbed the heat inside the holder support 3 is discharged to the thermostatic bath 30 through the flexible pipe 29. Here, the cooling water circulates between the rotating mechanism head and the external structure including the non-rotating constant temperature bath 30, and is mechanically relatively movable at the connection point between the two, and the cooling water is cooled. A bearing seal 31 is used to prevent water from leaking.

  This target support device allows the target surface position to be kept constant by moving the target in the direction of the rotation axis as much as the target surface is depleted by laser ablation at the same time as the target is rotated. . As a structure for that purpose, a magnetic seal box surrounding the laser ablation container (cluster generation container) 15 and the vacuum container 33 together with the rotation mechanism head, a rotation drive system including the motor 21, and a flexible pipe for the cooling water circuit. A bellows type linear drive mechanism 32 capable of changing the relative position is inserted between them.

The bellows type linear drive mechanism 32 includes an extendable bellows 32a and a drive screw rod 32b, and drives the rotary drive head linearly by rotating the drive screw rod 32b.
Note that the cooling water circulation path formed by the cooling water inflow pipe and the holder support portion is movable relative to the constant temperature bath fixed by the flexible pipes 28 and 29.

  FIG. 6 shows the characteristic features of the target holding device of the present invention, that is, the function of rotating the target, the function of linearly changing the target position, and the target generated by circulating cooling water in the vicinity of the target. In realizing the function of directly releasing heat to the outside, the method of driving the rotation and linear movement of the target holding device and the way of circulating the cooling water will be described as an example, and laser ablation that is the object of the present invention It is a figure explaining the mechanism regarding the atmospheric | air pressure control between the atmosphere around the target for 1 and air of 1 atmospheric pressure of the apparatus exterior. Accordingly, the necessary conventional techniques are omitted in FIG. For example, a bearing that mechanically supports the holder support 3, a magnetic seal box 24, a rotational drive system including a motor, and a cooling water inflow pipe 27 and a circulating water input / output unit connected thereto are mechanically coupled And the like.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this embodiment, A various change is possible in the range which does not deviate from the meaning of this invention.
For example, in the first embodiment described above, when the target 12 is accommodated in the recess 2a, the target 12 is fixed using the screw 2c. However, the present invention is not limited thereto, and the target 12 can be fixed using a fixing screw. Various fixing methods are conceivable.

In addition, for example, referring to the front view of FIG. 2B showing the first embodiment described above, the shape is circular. However, the shape is not limited to this, and the shape may be rectangular or polygonal.
For example, in the first embodiment described above, the cooling water is used as the cooling medium, but the present invention is not limited to this, and various liquids can be used.
Further, for example, in the second embodiment described above, one target fixing pin 5c is provided on the target rotation axis, but the present invention is not limited to this, and the target 12 is provided using a plurality of fixing pins near the rotation axis. It can also be fixed.

Further, for example, in the above-described embodiment, the target holding unit 2 and the holder support unit 3 are individually provided. However, the present invention is not limited to this, and the target holding unit 2 and the holder support unit 3 are integrally formed. You can also
Further, for example, in the above-described embodiment, silicon carbide is optimal. However, the present invention is not limited to this, and various substances can be used for the target holding unit 2 or the holder support unit 3 depending on the case.

It is the schematic which shows the whole structure of the cluster production | generation container to which the target holding apparatus which concerns on 1st Embodiment of this invention is applied. It is the longitudinal cross-sectional view (a) and top view (b) which show the structure of the target holding | maintenance apparatus which concerns on 1st Embodiment of this invention. It is the longitudinal cross-sectional view (a) and top view (b) which show the structure of the target holding | maintenance apparatus which concerns on 2nd Embodiment of this invention. It is a perspective view which shows the structure of the molybdenum target holder which concerns on 3rd Embodiment of this invention. It is a table | surface which shows the physical characteristic of the usage material of the target holder which concerns on 3rd Embodiment of this invention. It is a schematic diagram which shows the structural example of the rotational drive system and cooling medium circulation system which concern on 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,10 ... Target holding device, 2, 5 ... Target holder, 2a ... Concave part, 2b ... 1st cavity part, 2c ... Screw, 3 ... Holder support part, 3a ... 2nd cavity part, 4 ... Cooling medium, 5a ... concave portion, 5b ... first cavity portion, 5c ... target fixing pin, 5d ... target support site, 5e ... holder joint, 12 ... target, 13 ... entrance window, 14 ... shock wave, 15 ... cluster generation vessel, 16 ... Cluster group, 17 ... Outflow window, 18 ... Skimmer, 19 ... Substrate, 20 ... Cluster film, 21 ... Motor, 22 ... Belt, 24 ... Magnetic seal box, 25 ... Magnetic seal, 26 ... Internal vacuum space, 27 ... Cooling water Inflow pipe, 28, 29 ... Flexible pipe, 31 ... Bearing seal, 32 ... Bellows type linear drive mechanism, 32a ... Bellows, 32b ... Drive screw rod, 33 ... Vacuum container, 1 0 ... made of molybdenum target holder

Claims (8)

Target to be a target sample for laser ablation, fixing means for fixing the target, rotating means connected to the fixing means and rotating the target together with the fixing means, and cooling for cooling the target together with the fixing means Means,
Wherein the fixing means-edge has a fastener for fixing the target remains in the interior of the target without protruding on the surface layer of the target, 該留Me tool is the rotational center axis of the target The target holding device is characterized in that the temperature of the target surface is suppressed by being fixed only at the position, rotating the target by the rotating means, and cooling the target by the cooling means.   The inside of the fixing means is hollowed to the vicinity of the target, and the cooling means cools the fixing means and the target by circulating or refluxing a cooling liquid in the cavity of the fixing means. The target holding device according to claim 1.   The inert gas shock wave induced by the target material vapor generated by laser ablation in the inert gas atmosphere container is reflected by the container wall to confine the material vapor in a specific region, so that the material atoms constituting the material vapor or The target holding device according to claim 1, wherein the target holding device is attached to a cluster generation device that generates molecules by binding molecules.   2. The fixing means includes a target support portion that closely contacts and supports the target, and the target support portion and the fastener are made of a material having a thermal conductivity of 80 W / mK or more. The target holding device described in 1.   The fixing means includes a target support part that closely supports the target, and the target support part and the fastener are made of a material having a component other than the main component of 1 ppm or less. The target holding device according to claim 1.   The fixing means includes a target support part that closely supports the target, and the target support part and the fastener are made of a material whose maximum usable temperature is equal to or higher than the melting point of the target material. The target holding device according to claim 1. A fixing step of fixing a target to be a target sample for laser ablation with a fixing means;
A rotating step of rotating the target;
A cooling step for cooling the target;
Hints, with rotating the target by the rotation step, a target holding method for inhibiting high temperature of the target surface by cooling the target by said cooling step, the fixing means, is-edge, characterized in that remains inside the target without protruding on the surface layer of the target have a fastener for securing said target, 該留Me device is intended only for fixing at the position of the rotation center axis of the target Target holding method.   A laser ablation apparatus comprising the target holding device according to any one of claims 1 to 6.

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