JP2007258444A - Wafer protecting member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wafer protecting member enabling the conventional wafer processor to suitably process the wafer by converting into a usual waver profile shape, while appropriately utilizing the features, after thinning the wafer. <P>SOLUTION: A wafer, having a circular thinned central portion, is housed in a container 5 of a base 3 to compensate the thinned central portion of the wafer, thereby converting into a usual wafer profile shape. Thus, it is suitably processed, by using the conventional wafer processor, while well utilizing the feature after thinning the wafer. A through-hole 13 also has the effect of making the wafer easily separable from the base 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wafer protection member that protects a wafer such as a silicon semiconductor or a compound semiconductor when cleaning, etching, coating, or the like is performed with a processing liquid. The present invention relates to a technique for protecting a thinned wafer (also called thinning).

  In the thinning process for reducing the thickness of the wafer, at present, mechanical polishing in which the back surface of the wafer is mechanically polished using a grindstone is the mainstream. In this case, a temporary fixing tape is attached as a protective film to the surface of the wafer on which the device is formed, and the temporary fixing tape is peeled off after polishing the back surface of the wafer (see, for example, Patent Document 1). However, it is necessary to peel off the temporary fixing tape after the thinning process, and there is a problem that the wafer is warped due to a decrease in yield due to breakage of the wafer that has been thinned and reduced in strength or due to stress due to mechanical polishing.

Therefore, a method has been proposed in which the wafer is immersed in an etching solution such as a potassium hydroxide (KOH) solution to chemically thin the back surface of the wafer. At that time, in order to prevent the strength reduction and warpage of the thinned wafer, it has been proposed to protect the wafer with a special jig and thin only the central portion while leaving the peripheral portion of the wafer.
Japanese Patent Laying-Open No. 2005-123653 (FIG. 6)

However, the conventional example having such a configuration has the following problems.
That is, when processing the wafer surface after thinning the wafer, for example, even if the wafer surface is placed on a suction chuck with the wafer surface facing upward, a space is created at the center of the wafer, so that the wafer surface is sufficiently adsorbed. I can't. Moreover, there is a risk of damage if it is forcibly adsorbed. In other words, although the strength reduction and warpage can be prevented by the wafer remaining in the peripheral portion, there is a problem that the conventional wafer processing apparatus cannot perform processing properly.

  The present invention has been made in view of such circumstances, and appropriately utilizes a conventional wafer processing apparatus by converting it into a vertical sectional shape of a normal wafer while taking advantage of the characteristics after thinning the wafer. An object of the present invention is to provide a wafer protection member capable of processing a wafer.

In order to achieve such an object, the present invention has the following configuration.
That is, the invention according to claim 1 is the base member having a larger diameter than the outer diameter of the wafer, the peripheral portion of the back surface being left and the central portion being thinned in a circular shape with respect to the peripheral portion, and the base member And a storage section for storing the wafer, which is formed in accordance with the shape of the back surface of the wafer.

  [Operation / Effect] According to the invention described in claim 1, a wafer whose central portion is thinned in a circular shape with respect to the peripheral portion is stored in the storage portion of the base member. As a result, the thinned central portion of the wafer is compensated, and the wafer is converted into a normal longitudinal section of the wafer. Therefore, it is possible to appropriately perform processing with a conventional wafer processing apparatus while taking advantage of the characteristics after thinning the wafer.

  In the present invention, the storage portion includes a first recess having a depth substantially equal to a thickness at a central portion of the wafer from one surface of the base member, and a peripheral portion of the wafer from the one surface of the base member. And a second recess formed on the peripheral edge of the first recess according to the shape of the peripheral edge of the back surface of the wafer. ). Since the first concave portion and the second concave portion are formed in the storage portion, the surface of the wafer can be matched with the surface of the base member. Therefore, for example, the flow of the coating liquid can be made smooth even in the case of performing a process of spin-coating the coating liquid.

  In the present invention, it is preferable that the storage portion includes a plurality of through holes penetrating the other surface of the base member. When the wafer is placed on the base member, the air sandwiched between the wafers is discharged through the plurality of through holes, so that the wafer can be easily placed without being displaced in the horizontal direction. Further, when the base member is placed on the suction chuck, the wafer can be sucked together with the base member by sucking through the plurality of through holes, so that the base member can be firmly sucked and held. Can do.

  In the present invention, it is preferable that the surface of the first recess is subjected to non-specular treatment (claim 4). By separating the wafer from the base member by the non-specular surface treatment with the roughened surface, it is possible to prevent a situation where they are firmly adhered and difficult to separate.

  In the present invention, it is preferable that the base member has a standard diameter that is one size larger than the diameter of the wafer stored in the storage section. Processing can be performed by a standard wafer processing apparatus that processes a wafer that is one size larger without using a dedicated wafer processing apparatus of a special size. Therefore, special capital investment can be suppressed in manufacturing, and manufacturing cost can be reduced.

  The invention according to claim 6 is a base member having an outer diameter that is substantially the same as the outer diameter of a wafer that leaves the peripheral edge of the back surface and the center is thinned in a circular shape with respect to the peripheral edge; And a mounting portion on which the wafer is mounted on one surface of the base member so as to match the shape of the back surface of the wafer.

  [Operation / Effect] According to the invention described in claim 6, the base member is placed so as to cover the wafer whose center portion is thinned in a circular shape with respect to the peripheral portion. As a result, the thinned central portion of the wafer is compensated, and the wafer is converted into a normal longitudinal section of the wafer. Therefore, it is possible to appropriately perform processing with a conventional wafer processing apparatus while taking advantage of the characteristics after thinning the wafer. In addition, since the outer diameter of the wafer does not change, it is not necessary to use a wafer processing apparatus that processes a diameter one size larger.

  Further, in the present invention, the mounting portion has a convex portion having a height substantially equal to the depth at the center portion of the wafer and a length substantially equal to the width of the peripheral edge portion of the wafer, and the outer periphery of the convex portion. It is preferable to include a flange protruding from the surface. Since the convex portion and the flange portion are formed on the mounting portion and only the wafer is mounted, the surface of the wafer does not coincide with the surface of the base member so that no step is generated. Therefore, for example, even when processing such as spin coating of the coating liquid is performed, the flow of the coating liquid on the wafer surface can be made smooth.

  Moreover, in the present invention, it is preferable that the mounting portion includes a plurality of through holes penetrating the other surface of the base member (Claim 8), and the mounting portion has a non-mirror surface on the surface thereof. It is preferable that the treatment is performed (claim 9).

  In the present invention, the base member is preferably made of silicon or silicon carbide (SiC) (claim 10). When the wafer is silicon, the thermal expansion coefficient of the base member can be made the same as that of silicon by forming the wafer with silicon or silicon carbide. Therefore, even if it is the process heated to high temperature, it can process suitably.

  According to the wafer protection member of the present invention, the thinned central portion of the wafer is compensated for by storing the thinned wafer in the central portion in the accommodating portion of the base member. Is converted into a vertical cross-sectional shape. Therefore, it is possible to appropriately perform processing with a conventional wafer processing apparatus while taking advantage of the characteristics after thinning the wafer.

Embodiment 1 of the present invention will be described below with reference to the drawings.
1A and 1B show a wafer protection member according to a first embodiment, where FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along line 100-100. FIG. 2 is a schematic view showing attachment of the wafer to the wafer protection member.

  The wafer protection member 1 includes a base member 3 and a storage portion 5 formed on this surface (one surface). The base member 3 has a standard diameter that is one size larger than the wafer W. For example, when the wafer W has a diameter of 200 mm, the diameter is 300 mm. The base member 3 is made of a silicon wafer or silicon carbide (SiC) in consideration of the case where the wafer W is heat-treated. An orientation flat is formed when the wafer W has a diameter of 200 mm, and a notch is formed when the wafer W has a diameter of 300 mm.

  As shown in FIG. 2, the wafer W has a peripheral edge W1 on the back surface, and a central portion W3 is thinned in a circular shape with respect to the peripheral edge W1. The thinning process is performed by, for example, heating potassium hydroxide (KOH) with the peripheral edge W1 of the wafer W, the surface of the wafer W (upper surface in FIG. 2), and the outer peripheral surface covered with a highly chemical-resistant material. It is immersed in the solution for a predetermined time. Then, the central portion W3 of the wafer W is chemically etched to reduce the thickness. After the processing, the wafer W has, for example, a peripheral edge portion W1 having a thickness of 200 μm and a central portion W3 having a thickness of 60 μm.

  A notch 7 for alignment is formed at one part of the outer peripheral portion of the base member 3. In addition, a storage portion 5 is formed on the upper surface, which is one surface of the base member 3, and the storage portion 5 has a first recess 9 and a second second recess 11. The first recess 9 has a depth substantially equal to the thickness of the central portion W3 of the wafer W, and the second second recess 11 is formed in accordance with the shape of the peripheral edge W1 of the wafer W. The depth is approximately equal to the width and thickness of the portion W1. The second recess 11 is formed with a through hole 13 that penetrates the lower surface, which is the other surface of the base member 3, at a portion corresponding to each end of the cross shape in plan view. As for the 1st recessed part 9 and the 2nd 2nd recessed part 11, the surface blasting process of about No. 400 is given to the surface (bottom surface), and the surface is roughened.

  The wafer protection member 1 configured as described above is used as shown in FIGS. FIG. 3 is a view showing a state where the wafer protection member is placed on the suction chuck.

  First, the wafer W is mounted on the storage unit 5 with the back surface of the wafer W facing the storage unit 5 of the base member 3. At this time, the air sandwiched between the back surface of the wafer W and the upper surface of the base member 3 is exhausted to the outside through the through hole 13, so that the wafer W is displaced in the horizontal direction of the base member 3. Can be prevented and can be easily mounted.

  Next, the base member 3 is placed on the surface of the suction chuck 15 with the wafer W placed on the base member 3. The suction chuck 15 is formed with a plurality of suction ports 19 communicating with the upper surface of the base portion 17. Each suction port 19 is connected to the exhaust passage 21. The exhaust passage 21 is connected in communication with an exhaust source. After the base member 3 is placed on the suction chuck 15, when the exhaust is performed through the exhaust passage 21, the base member 3 is adsorbed on the surface of the base portion 17, and the wafer W is attached to the base through the through hole 13. The member 3 is adsorbed to the storage portion 5. Therefore, the wafer W can be firmly held by suction with respect to the suction chuck 15.

  In this manner, by storing the wafer W in which the central portion W3 is thinned in the circular shape in the accommodating portion 5 of the base member 3, the thinned central portion W3 of the wafer W is supplemented, and the normal wafer W is compensated. Is converted into a vertical cross-sectional shape. Therefore, it is possible to appropriately perform processing with a conventional wafer processing apparatus while taking advantage of the thinned characteristics of the wafer W.

  Further, since the first concave portion 9 and the second concave portion 11 are formed in the storage portion 5 of the base member 3, the surface of the wafer W can be made to coincide with the surface of the base member 3. Therefore, for example, even when a process of adsorbing and holding a rotating suction spin chuck (not shown) and rotating and applying the coating liquid is performed, the flow of the coating liquid at the peripheral edge of the surface of the wafer W is made smooth. be able to.

  Further, since the base member 3 is made of silicon or silicon carbide (SiC) having substantially the same coefficient of thermal expansion, the base member 3 is thermally expanded even when the wafer W is subjected to high-temperature heat treatment. Inconvenience due to the difference in rate can be avoided.

  Moreover, since the surface of the accommodating part 5 is roughened, when separating the wafer W from the base member 3, it can prevent that they adhere firmly and become difficult to isolate | separate. The through hole 13 also has an effect of facilitating separation when the wafer W is separated from the base member 3.

Embodiment 2 of the present invention will be described below with reference to the drawings.
4A and 4B show a wafer protection member according to the second embodiment, where FIG. 4A is a plan view and FIG. 4B is a cross-sectional view taken along the arrow 101-101. FIG. 5 is a schematic diagram showing attachment of the wafer to the wafer protection member.

  The wafer protection member 31 includes a base member 33 having an outer diameter comparable to the outer diameter of the wafer W, and a mounting portion 35 formed on the surface (one surface). The base member 3 is preferably made of a silicon wafer or silicon carbide (SiC) for the reasons described above. When the wafer W is 200 mm in diameter, an orientation flat is formed. In this case, an orientation flat 37 having the same shape as that formed on the wafer W is also formed on the base member 33.

  A mounting portion 35 is formed on the upper surface which is one surface of the base member 33, and the mounting portion 35 includes a convex portion 39 and a flange portion 41. The convex portion 39 has a height substantially equal to the depth at the central portion W3 of the wafer W. The flange 41 has a length substantially equal to the width of the peripheral edge W <b> 3 of the wafer W, and is formed so as to protrude from the outer peripheral surface of the protrusion 39. In addition, a through-hole 43 that penetrates the lower surface, which is the other surface of the base member 33, is formed in the flange portion 41 at a portion corresponding to each end portion of the cross shape in plan view. As for the convex part 39 and the collar part 41, the sandblasting process of about No. 400 is given to the surface (bottom surface), and the surface is roughened.

  Next, the wafer protection member 31 configured as described above is used as shown in FIGS. FIG. 6 is a view showing a state in which the wafer protection member is placed on the suction chuck. Since the suction chuck 15 is the same as that of the first embodiment, detailed description thereof will be omitted.

  First, in a state where the back surface of the wafer W faces the mounting portion 35 of the base member 33, the wafer W is mounted so that the central portion W <b> 3 of the wafer W is placed on the mounting portion 35. At this time, since the air sandwiched between the wafer W and the base member 33 is exhausted to the outside through the through-hole 43, the wafer W can be prevented from being displaced in the horizontal direction of the base member 33. It can be easily mounted.

  Next, the base member 33 is placed on the surface of the suction chuck 15 with the wafer W placed on the base member 33. After the base member 33 is placed on the suction chuck 15, when the air is exhausted through the exhaust passage 21, the base member 33 is attracted to the surface of the base portion 17, and the wafer W is attached to the base through the through hole 43. Adsorbed to the member 33. Therefore, the wafer W can be firmly held by suction with respect to the suction chuck 15.

  As described above, by placing the wafer W on the placement portion 35 of the base member 33, the central portion W <b> 3 of the wafer W is supplemented and converted to a normal longitudinal cross-sectional shape of the wafer W. Therefore, it is possible to appropriately perform processing with a conventional wafer processing apparatus while taking advantage of the thinned characteristics of the wafer W. In addition, since the outer diameter of the wafer protection member 31 of the second embodiment is not different from that of the wafer W, it is not necessary to use a wafer processing apparatus that processes a diameter one size larger.

  Further, since the convex portion 39 and the flange portion 41 are formed on the mounting portion 35 and only the wafer W is placed with the central portion W1 facing downward, the surface of the wafer W coincides with the surface of the base member 33. There is no such thing as a level difference. Therefore, for example, even when a process for spin-coating the coating liquid is performed, the flow of the coating liquid at the peripheral edge of the surface of the wafer W can be made smooth.

  Further, since the base member 33 is made of silicon or silicon carbide (SiC) having substantially the same coefficient of thermal expansion, the base member 33 is thermally expanded even when the wafer W is subjected to high-temperature heat treatment. Inconvenience due to the difference in rate can be avoided.

  In addition, since the surface of the mounting portion 35 is roughened, it is possible to prevent the wafer W from coming into close contact with the base member 31 and becoming difficult to separate. The through hole 43 also has an effect of facilitating separation when the wafer W is separated from the base member 33.

  The present invention is not limited to the above embodiment, and can be modified as follows.

  (1) Although the notch 7 is formed in the base member 3 in the above-described first embodiment, when the base member 3 of less than 200 mm is used depending on the diameter of the wafer W, the orientation is performed as in the second embodiment. -A flat should be formed.

  (2) The through holes 13 and 43 in the first and second embodiments are not essential and may not be provided. Instead of the through hole 13, the second hole is formed on the through hole communicating from the outer side surface of the second recess 11 to the outer peripheral surface of the base member 3, or on the upper surface extending from the second recess 11 to the outer peripheral surface of the base member 3. A concave groove extending radially from the concave portion 11 to the outer peripheral side of the base member 3 may be formed. Further, in place of the through-hole 43, a concave groove that radially expands from the flange 41 to the outer peripheral side may be formed on the upper surface of the flange 41. Furthermore, the through hole 13 may be formed at the center of the first recess 9, and the through hole 43 may be formed at the center of the protrusion 39.

  (3) The wafer protection members 1 and 31 are not limited to the processing after the placement on the suction chuck 15 and the rotation processing of the placement on the suction spin chuck. Even in the case of placing on a wafer cassette or storage shelf, or placing on a bake unit, it can be used.

The wafer protection member which concerns on Example 1 is shown, (a) is a top view, (b) is 100-100 arrow sectional drawing. It is a schematic diagram which shows the attachment of the wafer to a wafer protection member. It is a figure which shows the state which mounted the wafer protection member in the attraction | suction type chuck | zipper. The wafer protection member which concerns on Example 2 is shown, (a) is a top view, (b) is 101-101 arrow sectional drawing. It is a schematic diagram which shows the attachment of the wafer to a wafer protection member. It is a figure which shows the state which mounted the wafer protection member in the attraction | suction type chuck | zipper.

Explanation of symbols

W ... Wafer 1 ... Wafer protection member 3 ... Base member 5 ... Storage part 7 ... Notch 9 ... First recess 11 ... Second recess 13 ... Through hole 15 ... Suction chuck

Claims (10)

A base member having a larger diameter than the outer diameter of the wafer, leaving a peripheral edge on the back surface and having a central portion thinned in a circular shape with respect to the peripheral edge;
A storage portion for storing the wafer, formed on one surface of the base member in accordance with the shape of the back surface of the wafer;
A wafer protection member comprising: The wafer protection member according to claim 1,
The storage section is
A first recess having a depth substantially equal to a thickness at a central portion of the wafer from one surface of the base member;
A second recess having a depth substantially equal to the thickness at the peripheral edge of the wafer from one surface of the base member and formed at the peripheral edge of the first recess according to the shape of the back peripheral edge of the wafer; ,
A wafer protection member comprising: The wafer protection member according to claim 1 or 2,
The said protection part is provided with the some through-hole penetrated in the other surface of the said base member, The wafer protection member characterized by the above-mentioned. The wafer protection member according to claim 2 or 3,
The wafer protecting member, wherein the surface of the first recess is subjected to a non-mirror surface treatment. The wafer protection member according to claim 1,
The wafer protection member according to claim 1, wherein the base member is adapted to a standard diameter that is one size larger than a diameter of a wafer housed in the housing portion. A base member having an outer diameter that is the same as the outer diameter of the wafer, leaving the peripheral edge of the back surface, and the center being thinned in a circular shape with respect to the peripheral edge;
A mounting portion that is formed on one surface of the base member in accordance with the shape of the back surface of the wafer and mounts the wafer;
A wafer protection member comprising: The wafer protection member according to claim 6,
The placement section is
A convex portion having a height substantially equal to the depth at the center of the wafer;
A flange having a length substantially equal to the width of the peripheral edge of the wafer and protruding from the outer peripheral surface of the convex portion;
A wafer protection member comprising: The wafer protection member according to claim 6 or 7,
The wafer protection member according to claim 1, wherein the mounting portion includes a plurality of through holes penetrating the other surface of the base member. The wafer protection member according to any one of claims 6 to 8,
A wafer protection member, wherein the mounting portion is subjected to a non-mirror surface treatment on a surface thereof. The wafer protection member according to any one of claims 1 to 9,
The wafer protection member, wherein the base member is made of silicon or silicon carbide (SiC).

Images