JP2013042049A - Wafer support device - Google Patents

Abstract

There is provided a wafer support device having a novel structure which is superior in thermal efficiency without using a screw for generating particles.
A wafer support device 10 includes an electrostatic chuck 11, a thin plate member 15, and a fixing member 17, and a leg portion 18 of the fixing member 17 is formed on the thin plate member so as to surround a wafer mounting region. The opening 16 penetrates through the arranged opening 16 and protrudes upward from its upper surface, and the engaging portion 19 protrudes inward from its upper end. When the thin plate member and the fixing member are attracted and fixed to the electrostatic chucking surface of the electrostatic chuck, the wafer is fixed with the peripheral portion of the wafer sandwiched between the thin plate member and the engaging portion of the fixing member. Since the wafer is fixed in a state where it is sandwiched from above and below, the wafer does not fall off when used not only for normal upward use but also for downward or vertical use.
[Selection] Figure 1

Description

  The present invention relates to a wafer support apparatus used for supporting a wafer in a wafer process of semiconductor manufacturing such as CVD, sputtering, ion implantation, and etching.

  Supporting a wafer using a wafer support device in a semiconductor manufacturing wafer process such as CVD, sputtering, ion implantation, and etching is useful for heat equalization of wafers and batch processing of a plurality of wafers. . A conventional example of such a wafer support apparatus is described in Patent Document 1 below.

  In the wafer support apparatus described in Patent Document 1, the wafer 14 is placed on the inclined surface 28b of the central recess 28a of the susceptor 28, and the upper peripheral edge of the wafer 14 is pressed by a plurality of wafer pressing members 16, thereby Is supported from above and below (paragraphs 0028 to 0037, FIG. 1, etc.). The wafer retainer 16 is fixed to a substantially cylindrical holder 18 disposed so as to surround the susceptor 28 with bolts 20, extends along the side surface and the upper surface of the susceptor 28, and extends along the inclined surface 28 b of the recess 28 a. It protrudes diagonally downward.

  According to this wafer support apparatus, since the wafer is supported so as to be sandwiched from above and below, even when the wafer is in a vertical or downward state, the wafer can be prevented from falling off and reliably supported. There are advantages.

JP 2002-025989 A

  However, this wafer support apparatus has a big problem that the screw 20 is used to fix the wafer presser 16 and this screw becomes a particle generation source.

  Also, depending on the material of the wafer support device (for example, silicon), it is difficult to perform screw processing. Therefore, there is a limit to the material that can be used as the wafer support device, or processing accuracy is required. The rate drops.

  Further, when a low strength material such as carbon is used, it is necessary to increase the thickness in order to ensure the strength of the screw portion, and the heat conduction efficiency by the heater layer provided on the back surface side is reduced. For this reason, in order to heat the wafer to a predetermined temperature, the heat generation temperature of the heater layer must be set to be considerably higher than the wafer heating temperature, which requires large power consumption. Moreover, when it becomes thick, it becomes easy to warp with heat.

  In view of the above problems, the present invention prevents the generation of particles by adopting a structure that can securely fix a wafer without using a screw, and has excellent thermal efficiency and is less likely to warp by employing a thin plate structure. An object is to provide a novel wafer support apparatus.

  In order to achieve this object, the invention according to claim 1 is directed to an electrostatic chuck having at least one surface serving as an electrostatic chucking surface, a thin plate member placed on the electrostatic chucking surface of the electrostatic chuck, and the thin plate member A fixing member that is inserted into each of the plurality of openings penetrating in the thickness direction and fixes the wafer, and the fixing member passes through the opening of the thin plate member and protrudes upward from the upper surface thereof, and An engagement portion projecting inwardly from the upper end of the leg portion, and the thin plate member and the fixing member are attracted and fixed to the electrostatic chucking surface of the electrostatic chuck, A wafer support apparatus that fixes a wafer with a peripheral edge of the wafer sandwiched between an engaging portion of the fixing member.

  The invention according to claim 2 is the wafer support device according to claim 1, wherein the plurality of openings of the thin plate member are formed at positions surrounding the wafer in accordance with the size and shape of the wafer to be fixed. To do.

  The invention according to claim 3 is the wafer support device according to claim 1 or 2, wherein a plurality of wafers can be fixed to one thin plate member.

  According to a fourth aspect of the present invention, in the wafer support apparatus according to any one of the first to third aspects, it is possible to fix wafers having different dimensions within the range of the inward protruding length of the engaging portion of the fixing member. Features.

  According to a fifth aspect of the present invention, in the wafer support device according to any one of the first to fourth aspects, the fixing member has a bottom surface outside the opening edge in a state where the leg portion is inserted into the opening of the thin plate member. It has the overhang | projection part provided so that a slight clearance might be left between the surfaces of a thin plate member.

  According to the present invention, the thin plate member and the fixing member are attracted and fixed to the electrostatic chucking surface of the electrostatic chuck, so that the peripheral portion of the wafer placed on the thin plate member is engaged with the thin plate member and the fixing member. It is sandwiched between the two parts and securely fixed. As described above, according to the wafer support apparatus of the present invention, the wafer is fixed in a state of being sandwiched from above and below, so that the wafer does not fall off when used not only in the normal upward direction but also in the downward or vertical direction. That is, since the same effect can be obtained without using a screw as in the prior art described in Patent Document 1, generation of particles can be prevented.

  The thin plate member only needs to be processed to have an opening for penetrating the leg of the fixing member in a commercially available thin plate product such as a silicon wafer or a carbon thin plate, and the fixing member can also be easily processed from these commercially available materials. Therefore, it is possible to reduce the thickness and cost of the entire apparatus. As the thin plate member, for example, a member having a thickness of about 0.4 to 0.8 mm can be used, so that the adhesion to the electrostatic chucking surface of the electrostatic chuck is good, and heat transfer to the wafer is performed via this thin plate member. There is no loss of effectiveness. Warpage is also unlikely to occur.

  Further, since the wafer is fixed by pressing the peripheral edge of the wafer while being placed on the thin plate member by the engaging portion of the fixing member from the opposite side, the engaging portion is more than the opening edge of the thin plate member. It is possible to fix wafers having different dimensions as long as the size is within the range of the protruding length protruding inward.

  In addition, when the leg of the fixing member is inserted into the opening of the thin plate member, the overhanging portion is fixed so that the bottom surface is close to the surface of the thin plate member outside the opening edge and leaving a slight gap. By providing the member, it is possible to prevent the thin film from adhering to the electrostatic chuck attracting surface when the thin film is formed on the wafer fixed by using the wafer support device of the present invention.

It is sectional drawing which shows the wafer support apparatus by one Embodiment of this invention with the usage. It is a top view (a)-(c) which illustrates arrangement and shape of an opening formed in a thin plate member in this wafer support device. It is explanatory drawing which shows the example which made this wafer support apparatus the perpendicular | vertical (a) and downward (b).

  A wafer support apparatus according to an embodiment of the present invention will be described with reference to FIG. The wafer support device 10 also has a heater mechanism for securely supporting or fixing a wafer to be processed in a wafer process of semiconductor manufacturing such as CVD, sputtering, ion implantation, and etching, and for heating the wafer to a predetermined temperature. It is configured as a thing.

  The wafer support device 10 has an electrostatic chuck 11. The material and configuration of the electrostatic chuck 11 are not particularly limited as long as at least one surface can act as an electrostatic adsorption surface, and the material is ceramic, resin, or a metal surface with an electrically insulating coating. In addition, the electrode pattern may be a monopolar type or a bipolar type. As an example, a graphite substrate is insulated with a base coat of PBN, a PG electrode is disposed on the surface of the base coat, and a PG heating layer having a predetermined heater pattern is formed on the back surface. The electrostatic chuck 11 with a heater mechanism can be formed by insulation with an overcoat layer (see Japanese Patent No. 2756944). In this case, the upper surface of the electrode layer 12 formed on the surface of the electrostatic chuck 11 becomes the electrostatic adsorption surface 13, and the heat generated by the heating layer heater pattern 14 formed on the back surface is transferred through the electrostatic chuck 11. Heat the wafer.

  Since the structure and operation of the electrostatic chuck 11 itself are known by many conventional techniques and are not directly related to the subject of the present invention, illustration and description are omitted. In the present invention, any of the known electrostatic chucks 11 can be employed. The same applies to the structure and operation of the heater pattern 14 formed on the back surface of the electrostatic chuck 11. In addition, although the code | symbol 21 in a figure is a ground pin for making the thin plate member 15 and the fixing member 17 ground, when the ground pin 21 is not equipped, you may make it electrically ground through plasma etc. .

  The wafer support device 10 further includes a thin plate member 15 placed on the electrostatic chucking surface 13 of the electrostatic chuck 11. The thin plate member 15 is formed of a material having a specific resistance within a range where electrostatic adsorption can be performed at a high temperature or a low temperature and having a good workability such that it can be obtained as a thin plate having a thickness of about 0.4 to 0.8 mm. Specifically, ceramics such as aluminum nitride and SiC, metal, carbide, glassy carbon, glass, and the like can be used, but those processed (formed with openings 16) using a commercially available silicon wafer or carbon thin plate, etc. Use as the thin plate member 15 is particularly advantageous in terms of cost.

  In the thin plate member 15, a plurality of openings 16 are formed penetrating in the thickness direction so as to surround the mounting region of the wafer W to be processed. The opening 16 accommodates a leg portion of a fixing member, which will be described later, and is formed to have a shape and size substantially equal to the cross-sectional shape and size of the leg portion.

  FIG. 2 shows several examples of the arrangement and shape of the openings 16 formed in the thin plate member 15. In FIG. 2A, when a circular wafer W is a processing target, three rectangular openings 16 are formed at intervals of 120 degrees so as to surround the mounting area. In FIG. 2B, when a rectangular wafer W is a processing target, four rectangular openings 16 are formed at intervals of 90 degrees so as to surround the mounting area.

  These are merely examples, and other arrangement / shape examples may be adopted as long as the processing target wafer W can be reliably fixed in the manner described later. For example, in the case of FIG. 2A, the four rectangular openings 16 may be arranged at intervals of 90 degrees, and in the case of FIG. 2B, the four rectangular openings 16 are arranged at each vertex of the rectangular wafer W. It may be positioned close to. Or as shown in FIG.2 (c), you may form opening 16 'of the shape which has the circular arc-shaped inner surface 16a along the circular arc shape of the periphery of the circular wafer W, and if it is such an opening shape, An embodiment in which two openings 16 ′ are arranged to face each other at an interval of 180 degrees can also be adopted.

  Although FIG. 1 shows that one wafer W is fixed, it is also possible to configure as a wafer support device 10 that can fix a plurality of wafers W at the same time. In this case, a thin plate member 15 having a large diameter substantially the same size as the electrostatic chucking surface 13 of the electrostatic chuck 11 is used, and a plurality of wafer placement areas are set on the large diameter thin plate member 15 to each wafer. The opening 16 is disposed and formed so as to surround the mounting area. The plurality of wafer placement areas may all have the same shape and size, or in order to be able to process wafers of different shapes and sizes at the same time, set wafer placement areas of different shapes and sizes. Also good.

  The wafer support device 10 further includes a fixing member 17. The same number of the fixing members 17 as the openings 16 surrounding the wafer mounting area are used for each wafer mounting area set in the thin plate member 15.

  The fixing member 17 includes a leg portion 18 having a height that passes through the opening 16 of the thin plate member 15 and protrudes upward from the upper surface thereof, and an engagement portion 19 that protrudes inward from the upper end of the leg portion 18. Have. The leg portion 18 has substantially the same cross-sectional shape and dimensions as the opening 16, and the height thereof is formed to be substantially the same as the total thickness of the thickness of the thin plate member 15 and the thickness of the processing target wafer W. The engaging portion 19 has an inward protruding length so as to enter the wafer W mounting region above the thin plate member 16 when the leg portion 18 is inserted into the opening 16 (FIG. 1B) (FIG. 2). (Indicated by dotted lines in (a)-(c)).

  In this embodiment, the fixing member 17 is further shown as having an overhang 20. When the leg portion 18 is inserted into the opening 16 (FIG. 1B), the overhanging portion 20 leaves a slight gap between the bottom surface and the surface of the thin plate member 15 outside the edge of the opening 16. It is provided at a height position so as to be close to each other. By providing the overhanging portion 20, the thin film is prevented from adhering to the electrostatic chuck attracting surface 13 when the wafer W is fixed and the thin film is formed by using the wafer support device 10 as described later. can do. In addition, since a slight gap is left between the bottom surface of the overhanging portion 20 and the surface of the thin plate member 15, the thermal expansion of the wafer that occurs when the wafer W is heated while exhibiting the above-described effects. A difference in thermal expansion between the thin plate member 15 and the fixing member 17 can be absorbed.

  The fixing member 17 may be cut out from a commercially available block-like silicon product or carbon product, for example, and manufactured as an integrally molded product, having the leg portions 18 and the engaging portions 19 (and the overhang portions 20). Then, the parts produced as separate members from commercially available thin silicon products or carbon products may be integrated by bonding or the like to form the fixing member 17.

  Next, a method for fixing the wafer W using the wafer support apparatus 10 will be described.

  First, as described above, a plurality of openings 16 are formed in a commercially available silicon wafer or carbon thin plate so as to surround one or a plurality of wafer placement regions of the processing target wafer W, and the thin plate member 15 is prepared. The thin plate member 15 has a leg portion 18 inserted into each opening 16, an engagement portion 19 projecting inwardly from the upper end of the leg portion, and a fixed portion having a protruding portion 20 in this embodiment. The member 17 is prepared (FIG. 1 (a)).

  Then, the processing target wafer W is mounted on each wafer mounting region of the thin plate member 15, and the leg portion 18 is inserted into the opening 16 from above so that the peripheral portion thereof covers the engaging portion 19 of the fixing member 17. Since the height of the leg portion 18 (from the bottom surface to the lower surface of the engaging portion 19) is formed so as to substantially match the total thickness of the thin plate member 15 and the wafer W, the bottom surface of the leg portion 18 is the lower surface of the thin plate member 15. (FIG. 1B).

  Then, the wafer holder assembly (FIG. 1B) is transferred into the wafer process chamber by an optional transfer device (not shown) and placed on the electrostatic chucking surface 13 of the electrostatic chuck 11 (FIG. c)). Alternatively, after the thin plate member 15 is placed on the electrostatic chucking surface 13 of the electrostatic chuck 11, the processing target wafer W is placed on each wafer placement region, and the engaging portion of the fixing member 17 is placed on the peripheral edge thereof. The state shown in FIG. 1C may be obtained by inserting the leg 18 into the opening 16 from above so as to cover 19.

  When a predetermined voltage is applied to the electrode layer 12 in the state of FIG. 1C, the thin plate member 15 and the leg portion 18 are electrostatically attracted and fixed to the attracting surface 13 of the electrostatic chuck 11. Since the fixing member 17 is integrally formed including the leg portion 18, the wafer W is placed on the thin plate member 15, and the peripheral portion thereof is pressed by the engaging portion 19, and is firmly between them. Fixed mechanically.

  The wafer W fixed in this way is not only used when the wafer support device 10 is used upward, but also when the wafer support device 10 is vertical (FIG. 3A) or downward (FIG. 3 ( Also in b)), a predetermined wafer process can be performed without dropping. When the wafer is used vertically or downward after the predetermined wafer process is completed, it is returned to its original state (upward), and then the voltage applied to the electrostatic chuck 11 is released, and the wafer holder assembly (FIG. 1 (b) )) Is carried out of the wafer process chamber by the transfer device. Since the electrostatic attraction force with respect to the thin plate member 15 and the leg portion 18 has disappeared, the processed wafer W can be easily taken out by pulling out the leg portion 18 from the opening 16 and removing the fixing member 17. The arrows in the figure indicate the heat flow from the heat generating layer 14 to the wafer W.

DESCRIPTION OF SYMBOLS 10 Wafer support apparatus 11 Electrostatic chuck 12 Electrode layer 13 Electrostatic adsorption surface 14 Heat generation layer 15 Thin plate member 16, 16 'Opening 16a Arc-shaped inner surface 17 Fixing member 18 Leg part 19 Engagement part 20 Overhang part 21 Earth spin

Claims (5)

An electrostatic chuck having at least one surface serving as an electrostatic chuck surface, a thin plate member placed on the electrostatic chuck surface of the electrostatic chuck, and a wafer inserted into each of the plurality of openings penetrating the thin plate member in the thickness direction A fixing member for fixing the leg member, the fixing member passing through the opening of the thin plate member and projecting upward from its upper surface, and an engaging part projecting inward from the upper end of the leg part The thin plate member and the fixing member are attracted and fixed to the electrostatic chucking surface of the electrostatic chuck, so that the peripheral portion of the wafer is interposed between the thin plate member and the engaging portion of the fixing member. A wafer support apparatus for fixing a wafer with a pinch interposed therebetween. 2. The wafer support apparatus according to claim 1, wherein a plurality of openings of the thin plate member are formed at positions surrounding the wafer corresponding to the size and shape of the wafer to be fixed. 3. The wafer support apparatus according to claim 1, wherein a plurality of wafers can be fixed to one thin plate member. 4. The wafer support device according to claim 1, wherein wafers having different dimensions can be fixed within a range of an inward protruding length of the engaging portion of the fixing member. The fixing member is a protruding portion provided so that the bottom surface of the fixing member is close to the surface of the thin plate member outside the opening edge and leaving a slight gap when the leg portion is inserted into the opening of the thin plate member. The wafer support apparatus according to claim 1, further comprising: