JP4767276B2 - Vacuum container viewing window and vacuum container - Google Patents

Description

   The present invention relates to a viewing window and a vacuum container for observing the inside of a vacuum container used in a semiconductor manufacturing apparatus, an electronic device, or the like.

  Conventionally, the observation window of a vacuum vessel for observing the inside of a vacuum vessel used in a semiconductor manufacturing apparatus or an electronic device uses a plate-like window member made of glass, quartz, transparent synthetic resin, etc. Was sandwiched between two metal members having a frame shape or an annular shape, and the metal member was brazed to a vacuum vessel and bonded by a resin adhesive or the like. Alternatively, an opening is cut in the container, the outer peripheral portion of the window member is sandwiched between two metal members having a frame shape or an annular shape, and one of the metal members is bolted around the opening of the container. In this case, a single metal member may be used to sandwich the outer periphery of the window member between the metal member and the periphery of the opening of the container. Further, in the case of a viewing window incorporated in a vacuum vessel used in a semiconductor manufacturing apparatus or the like, the window member of the viewing window is made of two metals via a resin or metal O-ring for keeping the outer peripheral portion airtight. Airtightness has been ensured by sandwiching with members.

  However, in a vacuum vessel, heat treatment such as baking is performed to promote outgas from the inner surface of the vacuum vessel because it is necessary to reach a desired degree of vacuum in a short time, but peeping using a resin O-ring is performed. There is a problem that the O-ring cannot withstand the baking temperature in the window. Further, when a window made of a synthetic resin is used as the window member for the viewing window, there is a problem that the window member cannot withstand the baking temperature or cannot be used for a vacuum container due to a large amount of outgas.

  In order to solve such a problem, in recent years, a sapphire member has been used as a window member of a viewing window (for example, see Patent Document 1 below).

  Since the sapphire window member can be brazed with metal by applying a metallized layer on the surface, high airtightness is secured by brazing the sapphire window member to the metal member. A viewing window can now be produced. Moreover, since the gas emission from the surface of the window member made of sapphire is the same as that of metal, outgas is not a problem. Furthermore, since brazing can be performed using a brazing material having a melting point of 780 ° C. or higher, the airtightness can be sufficiently maintained even at a temperature of 250 to 350 ° C. which is a general baking temperature.

  However, the brazing of the sapphire window member and the metal member may not be able to ensure airtightness by cracking the window member unless the structure is determined after fully understanding the characteristics of the materials of the sapphire and the metal member. .

  In that case, the inside of the container cannot be sufficiently observed due to the crack of the window member. This is because the sapphire window member and the metal member have different thermal expansion coefficients, and when they are brazed at a high temperature and then cooled to room temperature, stress is generated in each member due to the difference in the thermal expansion coefficient. Because it does.

  For this reason, as a metal member material to which a sapphire window member is brazed, iron has a thermal expansion coefficient relatively close to that of sapphire and can be easily welded to stainless steel, which is most frequently used as a vacuum vessel material. An (Fe) -nickel (Ni) alloy, an iron (Fe) -nickel (Ni) -cobalt (Co) alloy, or the like is used. However, these metals also have a thermal expansion coefficient of about 5 × 10 −6 for sapphire, about 8 × 10 −6 for Fe—Ni alloy, and about 6 × 10 −6 for Fe—Ni—Co alloy. Since there is a difference in expansion coefficient, there is a problem that the window member breaks if the structure does not sufficiently relax the stress generated during brazing.

Further, as shown in the sectional view of FIG. 3, a step 11b is provided on the inner peripheral surface of the metal member 11 for positioning the window member 10, and the outer peripheral portion of one main surface of the window member 10 is brazed to the step 11b. The attached configuration may be used.
Japanese Patent Laid-Open No. 08-246148

However, in the viewing window having the conventional configuration shown in FIG. 3, the thickness of the metal member 11 from the step 11b, which is the brazing portion, to the one end is increased, so that the stress applied to the window member 14 during brazing increases.
That is, there is a problem that the corner of the step 11b on the inner peripheral surface of the metal member 11 applies a large stress to the corner of the window member 10 due to the deformation of the metal member 11 during brazing, and the window member 10 breaks. .

  Accordingly, the present invention has been completed in view of the above-described conventional problems, and its purpose is to improve the airtightness of the window member by improving the bonding strength of the window member and the metal member by brazing. Another object of the present invention is to provide a highly reliable viewing window that does not cause cracks in the window member by reducing the stress applied to the window member, and a vacuum container using the same.

  In order to solve the above problems, the present invention provides a vacuum comprising: a cylindrical metal member; and a window member disposed on an inner periphery of the metal member and joined to the metal member via a brazing material. In the viewing window of the container, the metal member has a convex portion facing the outer peripheral portion of one main surface of the window member on the inner peripheral surface, and is opposed to the convex portion on the one main surface of the window member. A vacuum viewing window is provided, wherein a metallizing layer is attached, and the metallizing layer is provided up to a position protruding toward the center of the window member from the convex portion.

  In addition, it is preferable that the meniscus of the brazing material is formed from the metallized layer to the inner peripheral surface of the convex portion.

  Moreover, it is preferable that the meniscus of the brazing material covers from the inner peripheral end of the metallized layer to the end of the inner peripheral surface of the convex portion opposite to the window member.

  Further, it is preferable that the metallized layer is attached so as to protrude from the convex portion toward the center of the window member by a length 0.5 to 2 times the axial thickness of the convex portion.

  Moreover, it is preferable that the thickness of the said convex part is 0.3 mm-2 mm.

  The present invention is also a vacuum container in which the viewing window is joined around an opening that penetrates the inside and the outside formed on the wall surface of the container, and the convex portion of the metal member with respect to the window member, A vacuum vessel is also provided, which is located inside the vessel.

The viewing window of the vacuum container of the present invention can reduce the stress applied to the window member from the metal member, and as a result, the window member can be prevented from cracking. In addition, the joint strength of the joint portion by brazing the window member and the metal member is improved, the air tightness of the window member is improved, and the stress applied to the window member from the metal member at the joint portion can be reduced. it can.
Therefore, it becomes a viewing window with high reliability of the joint. In addition, since the vacuum container of the present invention has a high reliability of the joint portion of the viewing window, the vacuum holding reliability is high.

  The viewing window of the present invention will be described in detail below. FIG. 1 is a sectional view showing an example of an embodiment of a viewing window according to the present invention. In this figure, 10 is a window member, 11 is a metal member, 11a is a convex part, 12 is a brazing material, and 13 is a metallized layer. FIG. 2 is a partially enlarged cross-sectional view of the vicinity of the brazing portion of FIG. 1 and 2, the same parts as those in FIG. 3 are denoted by the same reference numerals.

  The viewing window of the present invention includes a substantially cylindrical metal member 11, a substantially disk-shaped window member 10 made of sapphire whose side surface is joined to a part of its inner circumferential surface via a brazing material 12 over the entire circumference, and The metal member 11 has a convex portion 11a continuously formed over the entire circumference at a portion where the outer peripheral portion of one main surface of the window member 10 is joined to a portion where the window member 10 on the inner peripheral surface is joined. The window member 10 has the metallized layer 13 attached to the side surface over the entire circumference, and the axial direction of the convex portion 11a from the outer peripheral end to the center side of the window member 10 from the outer peripheral end to the outer peripheral portion of one main surface. The metallized layer 13 is deposited over the entire circumference up to a position protruding at a length 0.5 to 2 times the thickness of.

  As shown in FIG. 1, the viewing window of the present invention is provided with a convex portion 11 a on the inner peripheral surface of a metal member 11, and the window member 10 is disposed on the convex portion 11 a and brazed, thereby side surfaces of the window member 14. Compared with brazing with only brazing, the brazing area is greatly increased and the bonding strength is greatly improved.

  As for the length of the convex part 11a, ie, the protrusion length to the inner side from the internal peripheral surface of the metal member 11, 0.5-2 mm is preferable. If it is shorter than 0.5 mm, the brazing area between the convex portion 11a and the window member 10 cannot be sufficiently secured, and the effect of improving the bonding strength due to the provision of the convex portion 11a is reduced. On the other hand, if the thickness exceeds 2 mm, the stress in the radial direction during brazing due to the difference in the thermal expansion coefficient between the metal member 11 and the window member 10 increases, causing problems such as cracking of the window member 10. Furthermore, the effective visible region of the window member 10 is narrowed by the protrusion of the convex portion 11a.

  The axial thickness of the convex portion 11a is preferably 0.3 to 2 mm. If it is thinner than 0.3 mm, the strength is insufficient, and deformation due to stress during brazing increases. Also, deformation during processing becomes large, making it difficult to manufacture. If it is thicker than 2 mm, the stress applied to the window member 10 during brazing increases, and problems such as cracking of the window member 10 tend to occur.

  In the present invention, the metallized layer 13 formed in the brazed portion with the convex portion 11a of the window member 10 is formed to the center side of the convex portion 11a in the outer peripheral portion of one main surface of the window member 10. A smooth and large meniscus of the brazing material 12 can be formed at the center side end portion (inner end side end portion) of the window member 10 of the metallized layer 13. As a result, it is possible to relieve the stress caused by the difference in thermal expansion coefficient between the window member 10 and the metal member 11 that occurs during brazing.

  The protrusion length of the metallized layer 13 from the convex portion 11a to the center side of the window member 10 is 0.5 to 2 times (0.5 W or more) of the axial thickness W of the convex portion 11a, as shown in FIG. 2W). If it is less than 0.5 times, the meniscus of the brazing material 12 is not sufficiently formed, and the effect of relaxing the stress cannot be obtained sufficiently. On the other hand, if it is larger than twice, the brazing material 12 does not flow to the inner end of the metallized layer 13 and the effective visible region of the viewing window is narrowed, which is not preferable.

  Moreover, since the material of the metal member 11 is a metal close to the thermal expansion coefficient of sapphire, Fe—Ni alloy, Fe—Ni—Co alloy, molybdenum (Mo), platinum (Pt), titanium (Ti), Niobium (Nb) is preferable. Moreover, the material of the brazing material 12 is preferably a material that does not cause liquefaction such as melting at a high temperature of 400 to 600 ° C., and is based on Ag (based on Ag) or Au (based on Au). A brazing material such as Ag-Cu alloy is preferable.

  The metallized layer 13 formed on the window member 10 is made of Mo-Mn, W-Mn, Cu-Ti, Ag-Cu-Ti, etc., and has two layers with a nickel (Ni) plating layer deposited on the surface thereof. Structure. The thickness of the metallized layer 13 is preferably 5 to 30 μm, and if it is thinner than 5 μm, the adhesion strength of the metallized layer 13 is lowered due to erosion of the brazing material 12, and airtight tearing is likely to occur. The stress applied to the metallized layer 13 increases due to the difference in thermal expansion coefficient between the window member 10 and the window member 10, and the metallized layer 13 is easily cracked.

  In the vacuum container of the present invention, one end of the metal member 11 of the viewing window of the present invention is positioned on the inner side of the container with respect to the window member 10 around the opening formed on the wall surface of the container. To be joined. The metal member 11 is joined by brazing one end around the opening of the container made of metal, or by providing a collar on one end of the metal member 11 and bolting the collar around the opening of the container. Done.

  Further, the opening of the container may be an opening of a cylindrical portion such as a pipe provided so as to protrude from the container. The vacuum container of the present invention is used for a vacuum chamber of a semiconductor manufacturing apparatus, an electron accelerator (electron gun) of an electron microscope, a particle accelerator, etc., although not particularly shown.

   Examples of the viewing window of the present invention will be described below.

  As an example of the present invention, a viewing window having the configuration shown in FIG. 1 was manufactured as follows. A disk-shaped sapphire window member 10 having an outer diameter of 30 mm and a thickness of 2 mm was prepared. A metal paste obtained by mixing Mo powder, Mn powder, and silicon oxide (SiO2) powder with an organic binder and a solvent at a portion 3 mm wide from the side surface of the window member 10 and the outer peripheral edge of one main surface is 10 μm thick. A metallized metal layer as a base of the metallized layer 13 was formed by printing at a temperature of 1400 ° C. in a forming gas humidified after drying. Further, a Ni plating layer was deposited on the surface of the metallized metal layer to a thickness of about 2 μm by an electrolytic plating method to form a metallized layer 13.

  Next, it has a cylindrical shape with an inner diameter that is 0.1 mm larger than the outer diameter of the window member 10, a thickness of 0.5 mm, and a length of 30 mm, and a convex portion 11 a is formed at a portion of the inner peripheral surface 10 mm from one end. A metal member 11 made of an Fe—Ni—Co alloy was prepared. The protruding length to the inside of the convex portion 11a was 2 mm, and the axial thickness was 1 mm. A Ni plating layer was deposited on the entire surface of the metal member 11 to a thickness of about 2 μm by electrolytic plating.

  The window member 10 on which the metallized layer 13 is formed is arranged on the convex portion 11a on the inner side of the metal member 11 so that the portion where the metallized layer 13 is formed contacts one corner of the convex portion 11a. Furthermore, along the corner between the main surface of the window member 10 where the metallized layer 13 is not present and the inner peripheral surface of the metal member 11, the brazing material 12 having a diameter of 0.8 mm and made of an Ag—Cu alloy is used. A preform was installed. The preform of the brazing material 12 is heated to 820 ° C., the gap between the side surface of the window member 10 and the inner peripheral surface of the metal member 11, and the metallized layer 13 on the outer peripheral portion of one main surface of the window member 10, The molten brazing material 12 was caused to enter the gap between the convex portions 11a by capillary action, and the window member 10 and the metal member 11 were joined. The product thus manufactured was designated as Sample A.

  As Comparative Example 1, the protruding length to the inside of the convex portion 11a is 0.3 mm, the width of the metallized layer 13 from the outer peripheral end of one main surface of the window member 10 is 1.3 mm, and other than that in the above embodiment Sample B was similarly produced.

  As Comparative Example 2, the protrusion length to the inner side of the convex portion 11a was 3 mm, the width of the metallized layer 13 from the outer peripheral end of one main surface of the window member 10 was 4 mm, and the others were manufactured in the same manner as in the above embodiment. This was designated as Sample C.

  Table 1 shows the results of observing the joints of Samples A to C using a binocular microscope and examining the presence or absence of abnormalities.

  From Table 1, no abnormality was observed in Samples A and B, but in Sample C, the occurrence of cracks in the vicinity of the joint portion of the window member 10 with the convex portion 11a was observed for about two thirds.

Moreover, about another sample A and B manufactured similarly to the above, water was inject | poured from the side which does not have the convex part 11a of the metal member 11, and the value which a crack generate | occur | produces was investigated.
The results are shown in Table 2.

  From Table 2, it was found that Sample A had a greater pressure resistance than Sample B. Further, the deformation of the metal member 11 was larger in the sample B.

  In addition, another sample A manufactured in the same manner as described above, sample D in which the axial thickness of the convex portion 11a is 0.2 mm, and sample E in which the thickness is 3 mm are similarly manufactured, and the joint portion is observed with a binocular microscope. Table 3 shows the results of inspection for abnormalities.

From Table 3, sample A showed no abnormality.
In the sample D, the vicinity of the convex portion 11a of the metal member 11 was greatly deformed by the stress at the time of brazing. Moreover, generation | occurrence | production of the crack was confirmed for the sample E in the perimeter of joining part vicinity with the convex part 11a of the window member 10. FIG.

  In addition, another sample A manufactured in the same manner as described above, a sample F in which the protruding length of the metallized layer 13 to the inner side of the convex portion 11a is 0.2 mm, and a sample G in which the protruding length is 3 mm are also manufactured. Table 4 shows the results of examining the bonded portion with a binocular microscope for inspection.

  From Table 4, no abnormality was observed in sample A, but in sample F, it was confirmed that cracks occurred on the entire periphery in the vicinity of the joint portion with the convex portion 11a of window member 10. In Sample G, no abnormality was observed in the joint, but the brazing material 12 did not flow to the inner end of the metallized layer 13, so the brazing material 12 was not present in the inner portion of the metallized layer 13 with a width of about 1 mm. As a result, the effective visible region was narrowed as compared with Sample A.

  From the above, it was found that Sample A was excellent in terms of pressure resistance and effective visible region without cracking due to stress caused by the difference in thermal expansion coefficient between the window member 10 and the metal member 11. It should be noted that the present invention is not limited to the above-described embodiments and examples, and various modifications may be made without departing from the scope of the present invention. For example, the viewing window of the present invention can be used for observing the inside of a vacuum vessel that requires airtightness, but can also be used as a window for optically and electrically measuring an object inside the vacuum vessel.

It is sectional drawing which shows the example of embodiment about the observation window of this invention. It is an expanded sectional view of the brazing part vicinity in the inspection window of FIG. It is sectional drawing which shows an example of the conventional observation window.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Window member 11 Metal member 11a Convex part 12 Brazing material 13 Metallization layer

Claims (6)

A cylindrical metal member;
In the viewing window of the vacuum vessel, which is disposed on the inner peripheral portion of the metal member and is joined to the metal member via a brazing material,
The metal member has a convex portion on the inner peripheral surface facing the outer peripheral portion of one main surface of the window member,
A metallized layer facing the convex portion is attached to the one main surface of the window member,
The vacuum viewing window, wherein the metallized layer is provided up to a position protruding from the convex portion toward the center of the window member.   The viewing window for a vacuum vessel according to claim 1, wherein a meniscus of the brazing material is formed from the metallized layer to the inner peripheral surface of the convex portion.   The meniscus of the brazing material covers from the inner peripheral end of the metallized layer to the end of the inner peripheral surface of the convex portion opposite to the window member. Sight glass vacuum window.   The metallized layer protrudes and is attached to the center side of the window member with respect to the convex portion at a length of 0.5 to 2 times the axial thickness of the convex portion. Item 4. The observation window for the vacuum container according to any one of Items 1 to 3.   The viewing window of the vacuum container according to any one of claims 1 to 4, wherein a thickness of the convex portion is 0.3 mm to 2 mm. A vacuum container in which the observation window according to any one of claims 1 to 5 is joined to the periphery of an opening penetrating the inside and outside formed on the wall surface of the container,
The vacuum container, wherein the convex portion of the metal member is located on the inner side of the container with respect to the window member.

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