A method for etching a wafer with a gradient structure

Abstract

The invention discloses an etching method for a wafer with a gradient structure, which relates to the field of semiconductor technology, including: S1, controlling the rotation of the wafer, spraying an acid etching liquid on the upper surface of the wafer through a first nozzle, and driving the first nozzle to swing back and forth in an arc shape, and spraying a hot air flow to the center position and edge area of ​​the upper surface of the wafer; S2, spraying the acid etching liquid on a horizontal step surface through a second nozzle, and controlling the second nozzle to swing back and forth along the edge direction of the wafer; S3, spraying the acid etching liquid obliquely on a vertical step surface through a third nozzle. In the present invention, when the wafer is etched, a hot air flow is introduced into the surface and edge position of the wafer to achieve a heating action, and through the swing of the first nozzle, the second nozzle and the tilt angle of the third nozzle, the acid etching liquid can be fully covered on the surface and step surface of the wafer, which can improve the etching effect.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to an etching method for a wafer with a gradient structure. Background Art

[0002] In the manufacturing process of silicon wafers, wafers that are thinly sliced ​​from a single crystal ingot are generally flattened by chamfering and grinding. At this time, scratches of varying sizes or processing distortions are formed on the surface and back of the wafer due to the above processing. If these scratches or processing distortions become obvious in the later process, they may become serious quality problems. Therefore, the surface of the wafer is usually etched to remove these scratches or processing distortions.

[0003] In the prior art, etching is performed by directly spraying an acid etching solution onto the surface of the wafer. However, for a wafer having a step structure, this etching method makes it difficult to fully cover the surface of the wafer with the acid etching solution, which affects the etching effect. Summary of the invention

[0004] The object of the present invention is to provide a method for etching a wafer with a gradient structure, so as to solve the above-mentioned technical problems.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for etching a wafer with a gradient structure, wherein the edge of the upper surface of the wafer has a step surface, and the step surface includes a horizontal step surface and a vertical step surface connected to each other, comprising:

[0007] S1, controlling the wafer to rotate, spraying the acid etching solution on the upper surface of the wafer through the first nozzle, and driving the first nozzle to swing back and forth in an arc shape, while spraying hot air flow to the center position and edge area of ​​the upper surface of the wafer;

[0008] S2, spraying the acid etching liquid on the horizontal step surface through a second nozzle, and controlling the second nozzle to swing back and forth along the edge direction of the wafer;

[0009] S3, spraying the acid etching solution obliquely onto the vertical step surface through a third nozzle.

[0010] Furthermore, as a preferred embodiment, the swing angle of the first nozzle is 60 to 80 degrees.

[0011] Furthermore, as a preferred embodiment, the swing angle of the second nozzle is 30 to 90 degrees.

[0012] Further, as a preferred embodiment, the axis of the first nozzle is perpendicular to the upper surface of the wafer.

[0013] Further, as a preferred embodiment, the axis of the second nozzle is perpendicular to the horizontal step surface.

[0014] Further, as a preferred embodiment, the axis of the third nozzle points to the angle between the horizontal step surface and the vertical step surface.

[0015] The above technical solution has the following advantages or beneficial effects:

[0016] In the present invention, when etching the wafer, a hot air flow is introduced to the surface and edge of the wafer to achieve a heating action, and through the swing of the first nozzle and the second nozzle and the tilt angle of the third nozzle, the acid etching liquid can be fully covered on the surface and step surface of the wafer, which can improve the etching effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a flow chart of the etching method of the wafer with gradient structure in the present invention;

[0018] Figure 2 It is a structural schematic diagram of wafer cleaning in the present invention.

[0019] In the figure: 1. wafer carrying platform; 2. first nozzle; 3. second nozzle; 4. third nozzle; 5. wafer. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or position relationship indicated is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, if the terms "first", "second", "third" appear, they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] Figure 1 It is a flow chart of the etching method of the wafer with gradient structure in the present invention; Figure 2 This is a schematic diagram of the structure of the wafer cleaning in the present invention, see Figure 1 to Figure 2 As shown, a preferred embodiment is shown, which is a method for etching a wafer with a gradient structure, wherein the edge of the upper surface of the wafer 5 has a step surface, and the step surface includes a horizontal step surface and a vertical step surface connected to each other, including:

[0024] S1, control the rotation of the wafer 5, spray the acid etching liquid on the upper surface of the wafer 5 through the first nozzle 2, and drive the first nozzle 2 to swing back and forth in an arc shape, and spray a hot air flow to the center position and edge area of ​​the upper surface of the wafer 5; in this embodiment, the lower surface of the wafer 5 is a plane, and the lower surface of the wafer 5 can be etched by spraying the acid etching liquid through the fourth nozzle. The center position of the lower surface of the wafer 5 is also passed through a hot air flow for heating, which can accelerate the reaction rate of the acid etching liquid, making the etching faster and more sufficient.

[0025] S2, spraying the acid etching liquid on the horizontal step surface through the second nozzle 3, and controlling the second nozzle 3 to swing back and forth along the edge direction of the wafer 5;

[0026] S3, the acid etching solution is sprayed obliquely on the vertical step surface through the third nozzle 4. Figure 2 As shown, the wafer 5 is moved onto the wafer carrying platform 1 by a non-contact clamping method, and then the wafer 5 is controlled to rotate by the wafer carrying platform 1, and the acid etching liquid sprayed by the first nozzle 2 covers the surface of the wafer 5 and cooperates with the rotation of the wafer 5, so that the acid etching liquid flows around along the upper surface of the wafer 5, and flows to the horizontal step surface along the vertical step surface, and then converges at the edge of the wafer 5, and then the acid etching liquid is sprayed to the horizontal step surface of the wafer 5 by the second nozzle 3, and the acid etching liquid is sprayed to the vertical step surface of the wafer 5 by the third nozzle 4, so that the upper surface and the edge area of ​​the wafer 5 can be completely covered with the acid etching liquid, and at the same time, the temperature is controlled by adding a hot air flow, so that the reaction of the acid etching liquid can be accelerated, so as to improve the etching effect.

[0027] Further, as a preferred embodiment, the swing angle of the first nozzle 2 is 60-80°. In this embodiment, the first nozzle 2 swings back and forth along the diameter direction of the wafer 5, and the swing angle is preferably 60°.

[0028] Further, as a preferred embodiment, the swing angle of the second nozzle 3 is 30-90°. In this embodiment, the second nozzle 3 moves along the edge of the wafer 5 in an arc shape, and the swing angle is preferably 80°.

[0029] Further, as a preferred embodiment, the axis of the first nozzle 2 is perpendicular to the upper surface of the wafer 5 .

[0030] Further, as a preferred embodiment, the axis of the second nozzle 3 is perpendicular to the horizontal step surface.

[0031] Further, as a preferred embodiment, the axis of the third nozzle 4 points to the angle between the horizontal step surface and the vertical step surface. In this embodiment, the axial direction of the third nozzle 4 intersects with the line between the horizontal step surface and the vertical step surface, and the caliber of the third nozzle 4 is controlled to achieve the control of the spray angle range of the acid etching liquid, so that the acid etching liquid can completely cover the vertical step surface and part of the horizontal step surface, and the edge realizes the step surface of the wafer 5 without dead angle etching.

[0032] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for etching a wafer with a gradient structure, wherein the edge of the upper surface of the wafer has a step surface, and the step surface includes a horizontal step surface and a vertical step surface connected to each other, characterized in that: include: S1, controlling the wafer to rotate, spraying the acid etching solution on the upper surface of the wafer through the first nozzle, and driving the first nozzle to swing back and forth in an arc shape, while spraying hot air flow to the center position and edge area of ​​the upper surface of the wafer; S2, spraying the acid etching liquid on the horizontal step surface through a second nozzle, and controlling the second nozzle to swing back and forth along the edge direction of the wafer; the axis of the second nozzle is perpendicular to the horizontal step surface; S3, spraying the acid etching liquid obliquely onto the vertical step surface through a third nozzle; the axis of the third nozzle points to the angle between the horizontal step surface and the vertical step surface.

2. The method for etching a wafer having a gradient structure as claimed in claim 1, characterized in that: The swing angle of the first nozzle is 60-80°.

3. The etching method of a wafer with a gradient structure as claimed in claim 1, characterized in that: The swing angle of the second nozzle is 30-90°.

4. The method for etching a wafer having a gradient structure as claimed in claim 1, characterized in that: The axis of the first nozzle is perpendicular to the upper surface of the wafer.

Images