CN106711018B

CN106711018B - semiconductor wafer surface processing method

Info

Publication number: CN106711018B
Application number: CN201510783081.1A
Authority: CN
Inventors: 官振豪; 张延瑜
Original assignee: CRYSTALWISE Tech Inc
Current assignee: CRYSTALWISE Tech Inc
Priority date: 2015-11-16
Filing date: 2015-11-16
Publication date: 2019-12-10
Anticipated expiration: 2035-11-16
Also published as: CN106711018A

Abstract

the invention discloses a semiconductor wafer surface processing method, which is suitable for an electric discharge machining device, wherein the electric discharge machining device comprises an electric discharge electrode and a container filled with electric discharge machining liquid; the wafer surface processing method comprises the following steps: immersing the discharge electrode and the wafer in the container containing the discharge machining liquid, and driving the discharge electrode and the wafer to be close to each other; and providing electric energy to the discharge electrode and driving the discharge electrode to discharge near the first surface of the wafer so as to change the first surface shape of the wafer and create a required surface morphology. Alternatively, the second surface of the wafer may be subjected to a similar process to that described above to create a desired surface topography, or one of grinding, milling and chemical mechanical polishing to create a low warpage surface.

Description

Semiconductor wafer surface processing method

Technical Field

the present invention relates to semiconductor wafer processing, and more particularly, to a method for processing a semiconductor wafer surface to create a desired surface morphology of the wafer.

background

in the manufacturing process of semiconductor wafers, after the wafers are subjected to a plurality of processes, a large amount of stress is inevitably accumulated on the structure of the wafers, so that the wafers are deformed such as warped, and the warped deformation may be generated by the stress generated by grinding the wafers after the wafers are cut; or the thermal expansion coefficients of the multilayer structures in the wafer are different, so that the shrinkage force and the stress are not uniform when the wafer is annealed and recrystallized, and the warping of the wafer is further increased. In any case, the presence of wafer warpage causes the shape of the wafer to change, and when the shape of the wafer changes, many problems occur in the subsequent processes, such as: in the process of transporting and moving the wafer, besides the problem that the wafer Fork (Fork) is easy to scratch the surface of the wafer, the wafer may not be smoothly absorbed due to too large curvature of the warpage, so that the wafer is easy to slip and break; in addition, when the wafer is optically aligned, the alignment accuracy is also reduced; in addition, when the wafer is subjected to subsequent processes such as epitaxy, etching, photolithography, and diffusion processes, the uneven warpage on the surface of the wafer may affect the yield of the subsequent processes. In other words, how to effectively control or improve the warpage of the wafer is one of the problems that needs to be improved by the present companies.

referring to fig. 1, in order to eliminate the warpage of the wafer, it is common practice in the prior art to place the wafer 1 on the polishing pad 2 of the polishing machine, and apply pressure on the upper and lower surfaces of the wafer 1 to perform double-sided polishing or wheel polishing so as to process and remove a certain thickness on the upper and lower surfaces of the wafer 1, thereby reducing the warpage of the wafer 1. However, as shown in fig. 2, the above-mentioned method of grinding the surface of the wafer 1 by applying pressure to a certain thickness not only causes the cost problem of waste of the wafer material due to excessive removal amount of the wafer 1, but also causes the wafer 1 to rebound and return to the warped state due to release of the bending stress of the wafer 1 after the pressure applied to the wafer 1 by the grinder is released, and the problem of large warpage still exists, which is more obvious in the case of thinning the wafer thickness. It can be seen that there is still considerable room for improvement in the current methods for controlling the amount of warpage in a wafer.

disclosure of Invention

In view of the above, an object of the present invention is to provide a method for processing a surface of a semiconductor wafer, which can effectively control or improve the warpage of the wafer with a low removal amount; or to create a desired topography in the surface of the wafer.

in order to achieve the above object, the present invention provides a method for processing a surface of a semiconductor wafer, which is suitable for an electrical discharge machining apparatus, the electrical discharge machining apparatus including a discharge electrode and a container containing electrical discharge machining liquid; the wafer is provided with a first surface and a second surface which are opposite; the semiconductor wafer surface processing method comprises the following steps:

A. Immersing the discharge electrode and the wafer in the discharge machining liquid, and driving the discharge electrode and the wafer to be close to each other; and

B. Providing electric energy to the discharge electrode to discharge the first surface of the wafer to remove the material to be processed, and changing the surface morphology of the first surface of the wafer by controlling the material removal amount in different areas.

the invention has the advantages that the surface of the wafer is subjected to discharge machining through the discharge electrode, so that the problem of reducing and improving the warping amount of the wafer can be solved under the condition of small removal amount; in addition, the relative movement between the discharge electrode and the wafer can also create the wafer surface morphology required by the user.

drawings

FIG. 1 is a schematic diagram of a wafer being polished by a polishing machine;

FIG. 2 is a schematic diagram illustrating a wafer polished by a conventional polishing machine;

FIG. 3 is a schematic view of a discharge electrode discharging electricity to a semiconductor wafer according to a first preferred embodiment of the present invention;

FIG. 4 is a schematic view of the wafer surface processing method of the semiconductor according to the preferred embodiment, after the first surface of the wafer is finished by electro-discharge machining;

FIG. 5 is a schematic view of a discharge electrode discharging electricity to a semiconductor wafer according to a second preferred embodiment of the present invention;

FIG. 6 is a schematic view of a discharge electrode discharging electricity to a semiconductor wafer according to a third preferred embodiment of the present invention;

FIG. 7 is a schematic view of a linear discharge electrode discharging electricity to a semiconductor wafer according to a fourth preferred embodiment of the present invention;

FIG. 8 is a schematic view of a linear discharge electrode discharging electricity to a semiconductor wafer according to a fifth preferred embodiment of the present invention;

FIG. 9 is a schematic view of a discharge electrode discharging electricity to a semiconductor wafer according to a sixth preferred embodiment of the present invention;

Fig. 10 is a schematic view of a discharge electrode discharging electricity to a semiconductor wafer according to a seventh preferred embodiment of the present invention.

[ description of reference ]

[ Prior Art ]

1 wafer

2 grinding pad

[ invention ]

10 mechanical arm

20 discharge electrode

201 working surface

30 container

40 bearing seat

50 wafer

501 first surface 502 second surface

21-24 discharge electrodes

211 curved surface 221 working surface

231 working section 241 working face

51-55 wafer

511 to 531 surfaces

Detailed Description

In order to more clearly illustrate the present invention, a preferred embodiment is described in detail below with reference to the accompanying drawings. The semiconductor wafer surface processing method of the present invention is used for processing the surface of a wafer, for example: the 4H crystal phase N-type silicon carbide wafer with semiconductor characteristics is used for controlling, improving or eliminating the warping amount of the wafer or changing the surface of the wafer into the surface form required by the process. The wafer may be a silicon carbide wafer sliced from a wafer column by a multi-line cutting process (or a grinding process), or a silicon carbide wafer polished or sliced from a wafer column by another process (e.g., diffusion, photolithography, etching, ion implantation or a thin film) in which the warpage or surface morphology of the wafer is to be improved. The cutting or grinding plate is used to create a datum plane for subsequent processing, and the polishing or other processes are used to control the amount of warping by the processing and trimming of the back surface. In addition, the method for processing the surface of the semiconductor wafer according to the present invention is particularly suitable for processing a single crystal silicon carbide wafer having high hardness, and the flatness, surface roughness, and the like of the processed wafer can be preferably obtained.

Referring to fig. 3 and 4, a semiconductor wafer surface processing method according to a first preferred embodiment of the present invention is suitable for an electrical discharge machining apparatus, which includes a robot 10, a discharge electrode 20, a container 30 containing an electrical discharge machining liquid, and a holder 40. The mechanical arm 10 is connected to the discharge electrode 20 for controlling the movement and/or rotation of the discharge electrode 20, and the mechanical arm 10 is further provided with a transmission line connected to the discharge electrode 20 for transmitting electric energy to the discharge electrode 20 for discharging and transmitting a control signal for controlling the intensity of the discharge energy and the discharge pulse frequency of the discharge electrode 20; the discharge electrode 20 is plate-shaped and has a working surface 201 for discharging electric energy; the electrical discharge machining liquid contained in the container 30 may be selected from an emulsified machining liquid with good lubricating and cooling effects, an oily machining liquid such as kerosene, or an aqueous machining liquid such as distilled water or deionized water, wherein the selection of the electrical discharge machining liquid is not one of the limiting requirements of the present invention, and can be selected according to the characteristics of the wafer according to the requirements; the susceptor 40 is used for carrying a wafer 50 and controlling the wafer 50 to move and/or controlling the wafer 50 to rotate along its axis. The wafer 50 has a first surface 501 and a second surface 502 opposite to each other, and as can be seen from fig. 3, both the first surface 501 and the second surface 502 of the wafer 50 have warp deformation.

The semiconductor wafer surface processing method of the invention comprises the following steps:

Step A, immersing the discharge electrode 20 and the wafer 50 in an electrical discharge machining liquid, and driving the discharge electrode 20 and the wafer 50 to approach each other. In the embodiment, the susceptor 40 is disposed at the bottom of the container 30, the second surface 502 of the wafer 50 is vacuum-held by the susceptor 40 and fixed on the susceptor 40, and the susceptor 40 can also control the rotation of the wafer to increase the processing uniformity as required, although the rotation shaft for controlling the rotation can be additionally disposed at one side of the robot 10. The first surface 501 of the wafer 50 faces upward to face the working surface 201 of the discharge electrode 20, wherein the working surface 201 of the discharge electrode 20 is greater than or equal to the first surface 501 or the second surface 502 of the wafer, and in this embodiment, the working surface 201 is slightly larger than the first surface 501 of the wafer. Thus, the robot 10 can be controlled to move toward the wafer 50 to drive the working surface 201 of the discharge electrode 20 to be gradually close to the first surface 501 of the wafer 50.

When the discharge electrode 20 and the wafer 50 approach each other within a predetermined distance range, the next step is performed: step B, providing electrical energy to the discharge electrode 20 to discharge the discharge electrode 20 to the first surface 501 of the wafer 50, so as to change the surface morphology of the first surface of the wafer 50.

in the present embodiment, a control panel supplies the electric energy required for the pulse discharge to the discharge electrode 20 and the control signal for determining the data such as the intensity and frequency of the discharge energy through the transmission line on the robot arm 10, so as to cause the working surface 201 of the discharge electrode 20 to perform the pulse discharge on the first surface 501 of the wafer 50. Accordingly, an ion channel with a strong electric field is formed between the first surface 501 of the wafer 50 and the working surface 201, and a discharge phenomenon occurs, so that the first surface 501 of the wafer 50 is dissociated, melted, or vaporized by ions, and accordingly, the surface morphology of the first surface 501 of the wafer 50 can be changed into a surface morphology complementary to the working surface 501 through multiple pulse discharges. In the present embodiment, the working surface 501 of the discharge electrode 20 is a plane, so as shown in fig. 4, after step B is performed, the first surface 501 of the wafer 50 forms a flat surface complementary to the working surface 501, thereby improving the warpage of the first surface 501 of the wafer 50.

in addition, after the step B, the first surface 501 of the wafer 50 may be subjected to grinding, chemical mechanical polishing, etc. to further obtain a flatter first surface 501 with lower surface roughness, or to create a finer and undamaged atomically flat surface, which is beneficial for the subsequent processes of the wafer 50.

Then, when the warpage of the second surface 502 of the wafer 50 is to be improved or the surface type of the second surface 502 of the wafer 50 is to be changed, in addition to performing at least one of grinding, grinding and chemical mechanical polishing processes on the second surface 502 of the wafer 50, after step B, a step C of turning over the wafer 50 so that the second surface 502 of the wafer 50 faces the discharge electrode 20 is further included; and driving the discharge electrode 20 and the wafer 50 to approach each other, and providing electrical energy to the discharge electrode 20 to drive the discharge electrode 20 to discharge to the second surface 502 of the wafer 50, so as to change the surface morphology of the second surface 502 of the wafer 50. The difference between the step C and the step B is that the method further includes a step of flipping the wafer 50 to direct the surface of the wafer 50 that has not been subjected to surface processing toward the discharge electrode 20, i.e., to make the second surface 502 of the wafer 50 face the working surface 201 of the discharge electrode 20, so as to change the second surface 502 of the wafer 50 to a desired plane or surface shape by the pulse discharge of the discharge electrode 20.

In order to obtain a finer second surface for facilitating the subsequent processing of the wafer, step D is further included after step C, wherein the first surface 501 and/or the second surface 502 of the wafer 50 are subjected to one of grinding, grinding and chemical mechanical polishing processes. In this step, the wafer surface having passed through the edm process is further finely processed to create a flatter and less rough surface, but if the wafer has reached the required flatness after the edm process, step D may not be executed, and the embodiment of executing step D is not limited thereto.

it should be noted that, the wafer surface processing method of the present invention not only can improve the problem of warpage of the wafer, but also can create a desired surface on the surface of the wafer according to the process requirements, such as: curved surfaces, even those with points of inflection. Referring to fig. 5, a wafer surface processing method according to a second preferred embodiment of the present invention is different from the previous embodiment in that the working surface of the discharge electrode 21 includes a curved surface 211, so that the first surface 511 of the wafer 51 after the discharge processing in step B has a surface shape complementary to the curved surface 211.

In addition to the processing method of the plate-shaped discharge electrode, referring to fig. 6, a wafer surface processing method according to a third preferred embodiment of the present invention is shown, and unlike the previous embodiments, the discharge electrode 22 of the present embodiment is a rod-shaped electrode, and the area of the working surface 221 of the discharge electrode 22 is substantially smaller than the area of the surface 521 of the wafer 52, so that when the discharge electrode 22 discharges the wafer 52 in step B, at least one of the discharge electrode 22 and the wafer 52 can be driven to rotate and/or move, for example: the wafer 52 can be driven to rotate, and the discharge electrode 22 is sequentially moved from the outer periphery of the wafer 52 to the center of the wafer 52 in coordination with the rotation of the wafer 52 by one cycle, and when the wafer 52 rotates by one cycle, the discharge electrode 22 is controlled to further move towards the center of the wafer 52 by a preset distance in coordination with the adjustment of the vertical distance between the discharge electrode 22 and the wafer 52, so that the surface morphology of the wafer 52 with ring grains can be formed on the surface 521 of the wafer 52, and the difference of the ring grains depends on the size of the electrode, the shape of the electrode, the setting of the distance between the rings, the relative movement speed between the electrode and the wafer, the discharge voltage, the conductivity of the wafer material, and the like. In addition, the discharge electrode 22 and the wafer 52 can be controlled to form other different types of movements to generate other different wafer surface shapes, but not limited thereto.

Referring to fig. 7, a wafer surface processing method according to a fourth preferred embodiment of the present invention is different from the foregoing embodiments in that the discharge electrode 23 applied in this embodiment is a linear electrode having a working segment 231 with a substantially linear shape for discharging electricity to the wafer 53, and the working segment 231 is disposed in a manner substantially parallel or approximately parallel to the surface 531 of the wafer 53, or the relative positions of the working segment 231 and the surface 531 of the wafer 53 can be adjusted according to the design requirements of other wafer surface forms, and in step B, when the working segment 231 of the discharge electrode 23 discharges electricity to the surface 531 of the wafer 53, the working segment of the discharge electrode 23 is driven to move along the radial direction of the wafer 53, so as to process a desired plane or other form surface on the surface 531 of the wafer 53; referring to fig. 8, in addition to the discharge electrode 23 driven to move along the radial direction of the wafer in the foregoing embodiment, the wafer 53 may be driven to move or rotate to form a desired wafer surface shape according to the wafer surface processing method in the fifth preferred embodiment of the present invention; alternatively, the working segment 231 of the discharge electrode 23 is moved to an axis perpendicular to the wafer 53 and the wafer 53 is rotated to form the desired wafer surface morphology. In other words, the user can preset the relative movement between the discharge electrode and the wafer or the rotation of the wafer according to the requirement, so as to process the required plane, and the embodiment is not limited to the above.

it should be noted that the relative positions of the wafer and the discharge electrode are not limited to the description of the above embodiments. For example, referring to fig. 9, a wafer surface processing method according to a sixth preferred embodiment of the present invention is different from the first embodiment in that the discharge electrode 24 is disposed on the bottom surface of the container 30, and the working surface 241 is upward; the wafer 54 to be surface processed is suspended above the container 30 and is controlled to approach the discharge electrode 24 for processing the surface of the wafer. In addition, referring to fig. 10, a wafer surface processing method according to a seventh preferred embodiment of the present invention is different from the first preferred embodiment in that a susceptor for supporting and fixing a wafer 55 is disposed on a sidewall surface of the container 30, the wafer 55 is designed to be vertical, and a discharge electrode 25 adapted to the wafer 55 is also designed to be vertical, so that the wafer surface processing method according to the present invention can be performed. Thus, it can be seen from the foregoing embodiments that the wafer surface processing method of the present invention is applicable to various combinations of the relative positions of the discharge electrode and the wafer.

when the discharge electrode performs the electrical discharge machining process on the wafer, an ultrasonic generator may be disposed in the container to provide ultrasonic oscillation energy to assist the removed object to leave the surface of the wafer, and the surface roughness of the wafer may be homogenized by matching with the machining liquid with the added micro-abrasive particles to assist the surface electrical discharge machining process on the wafer, so that the removed amount of the wafer is more uniform and the surface of the wafer is more flat.

The semiconductor wafer surface processing method can be suitable for wafers of various sizes, and can achieve the effect of improving or controlling the warping amount of the wafer under the condition of low wafer removal amount. For example, please refer to the table in the following table, which is a comparison table of the wafer removal amount and the wafer warpage amount after performing various surface processing on the 2 nd and 4 th wafers, wherein, as can be seen from the table in the first step, the 2 nd wafer after wire cutting generally has a warpage amount of 10-60 um; the wafer after the wire-cutting process of 4 hours generally has a warpage amount of 10-100 um. As can be seen from the table I, the semiconductor wafer surface processing method of the present invention has the lowest wafer removal amount in both the case of 2-hour wafer and the case of 4-hour wafer, and the wafer warpage amount after processing is relatively low, i.e., the semiconductor wafer surface processing method of the present invention can achieve a lower wafer removal amount compared to the prior art, and can control the warpage amount of the wafer more effectively.

Watch 1

in summary, the semiconductor wafer surface processing method of the present invention, through the electrical discharge machining and the control of the material removal amount in different areas, not only can obtain better wafer warpage control under the condition of lower wafer removal amount, but also can form a plane or a curved surface required by the process on the surface of the wafer according to the requirement of the user, so as to facilitate the subsequent processes, for example: the effect application of the wafer surface pre-deformation can be made according to the deformation possibly caused by the subsequent process. In addition, the semiconductor wafer surface processing method adopts an electric discharge processing mode, and the discharge electrode does not directly apply pressure to the wafer, so that the problem that the wafer rebounds to cause warpage still exists after the surface processing is finished is solved.

It should be noted that the aforementioned wafer may be a SiC single crystal wafer or other types of semiconductor wafers such as silicon wafer, gallium arsenide, gallium nitride, etc., and is not limited to the aforementioned 4H crystal phase N-type silicon carbide wafer. Furthermore, when the semiconductor wafer surface processing method is applied to a wafer with the resistivity of 0.001-1 ohm-cm, the warping amount of the wafer can be effectively reduced.

In addition, because the surface stress is still caused by a certain damage layer on the surface of the wafer after slicing or grinding, the processed surface can generate warping change due to the difference of the surface stress of the two surfaces after electric discharge processing, therefore, before the step A or before processing, the wafer can be subjected to high-temperature heat treatment to release the stress, so as to reduce the warping change and warping degree.

It should be noted that the multi-wire cutting process may be a diamond slurry plus wire cutting process, a diamond wire cutting process, or a multi-wire electrical discharge cutting process. The electrical discharge surface machining process removes the wafer material by the electrical discharge machining device according to the set relative movement to form the required surface morphology and surface roughness. The grinding process such as grinding, grinding and the like can be performed by single-side waxing bonding or double-side adhesive bonding, and then using diamond abrasive grains with a certain particle size and a grinding disc, wherein the particle size of the diamond abrasive grains is 0.5-10 um, and the grinding disc can be a cast iron disc, a resin copper disc, a pure copper disc, a tin disc or a soft polishing pad.

In addition, the grinding process may be performed using a grinding wheel of sintered diamond particles. It should be noted that the grinding procedure or the wheel grinding procedure is not necessarily used, and there is no specific sequence between them, i.e. the wheel grinding procedure and the grinding procedure are performed first or the wheel grinding procedure is performed first. In other words, whether polishing or grinding process is used during the wafer surface processing or not, the scope of the present invention should be encompassed.

The above is only a preferred embodiment of the present invention, and when the wafer surface processing method is performed, the second surface may be processed first, and then the first surface may be processed. In addition, the surface morphology of the wafer to be processed is only used as an exemplary illustration, and is not limited to the warpage with the concave first surface and the convex second surface.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A semiconductor wafer surface processing method is suitable for an electric discharge machining device, the electric discharge machining device comprises an electric discharge electrode and a container containing electric discharge machining liquid, wherein the electric discharge electrode is provided with a working surface, and the working surface faces to the wafer and is used for discharging electricity to the wafer; the wafer is provided with a first surface and a second surface which are opposite, and the area of the working surface is larger than or equal to that of the first surface of the wafer; the semiconductor wafer surface processing method comprises the following steps:

B. Providing electric energy to the discharge electrode to discharge the discharge electrode to the first surface of the wafer so as to change the surface morphology of the first surface of the wafer, and driving the wafer to rotate when the discharge electrode discharges to the wafer.

2. The method as claimed in claim 1, wherein the wafer has a resistivity of 0.001 to 1 ohm-cm.

3. The method according to claim 1, wherein the wafer is one of a SiC single crystal wafer, a silicon wafer, a GaAs semiconductor wafer, and a GaN semiconductor wafer.

4. A semiconductor wafer surface processing method is suitable for an electric discharge machining device, the electric discharge machining device comprises an electric discharge electrode and a container containing electric discharge machining liquid, wherein the electric discharge electrode is provided with a working surface, the working surface comprises a curved surface, and the working surface faces to the wafer and is used for discharging the wafer; the wafer is provided with a first surface and a second surface which are opposite; the semiconductor wafer surface processing method comprises the following steps:

B. Providing electric energy to the discharge electrode to discharge the discharge electrode to the first surface of the wafer so as to change the surface morphology of the first surface of the wafer, wherein the first surface of the wafer forms a surface morphology complementary to the curved surface.

5. A semiconductor wafer surface processing method is suitable for an electric discharge machining device, the wafer is provided with a first surface and a second surface which are opposite, the electric discharge machining device comprises an electric discharge electrode and a container containing electric discharge machining liquid, wherein the electric discharge electrode is provided with a working surface, the area of the working surface is smaller than that of the first surface of the wafer, and the working surface faces the wafer and is used for discharging the wafer; the semiconductor wafer surface processing method comprises the following steps:

B. Providing electrical energy to the discharge electrode to discharge the discharge electrode to the first surface of the wafer, and simultaneously driving at least one of the discharge electrode and the wafer to rotate and/or move to change the surface morphology of the first surface of the wafer.

6. A semiconductor wafer surface processing method is suitable for an electric discharge machining device, the wafer is provided with a first surface and a second surface which are opposite, the electric discharge machining device comprises a discharge electrode and a container containing electric discharge machining liquid, wherein the discharge electrode is a linear electrode, the discharge electrode is provided with a linear working section, and the working section is parallel to the first surface of the wafer and used for discharging the wafer; the semiconductor wafer surface processing method comprises the following steps:

B. Providing electric energy to the discharge electrode, so that the discharge electrode discharges to the first surface of the wafer, and simultaneously driving the discharge electrode to move along the radial direction of the wafer and/or driving the wafer to rotate, so as to change the surface form of the first surface of the wafer.

7. A semiconductor wafer surface processing method is suitable for an electric discharge machining device, and the electric discharge machining device comprises an electric discharge electrode and a container containing electric discharge machining liquid; the wafer is provided with a first surface and a second surface which are opposite; the semiconductor wafer surface processing method comprises the following steps:

B. Providing electric energy to the discharge electrode, so that the discharge electrode discharges to the first surface of the wafer to change the surface morphology of the first surface of the wafer, and then performing at least one of grinding, grinding and chemical mechanical polishing to the first surface of the wafer.

8. A semiconductor wafer surface processing method is suitable for an electric discharge machining device, and the electric discharge machining device comprises an electric discharge electrode and a container containing electric discharge machining liquid; the wafer is provided with a first surface and a second surface which are opposite; the semiconductor wafer surface processing method comprises the following steps:

B. providing electric energy to the discharge electrode to discharge the first surface of the wafer by the discharge electrode so as to change the surface morphology of the first surface of the wafer;

C. turning over the wafer to make the second surface of the wafer face the discharge electrode; and

The discharge electrode is driven to approach the wafer and provide electric energy to the discharge electrode to discharge the second surface of the wafer so as to change the surface morphology of the second surface of the wafer.

9. The method of claim 8, further comprising a step D of performing at least one of grinding, grinding and chemical mechanical polishing on the first surface and/or the second surface of the wafer after the step C.

10. a semiconductor wafer surface processing method is suitable for an electric discharge machining device, and the electric discharge machining device comprises an electric discharge electrode and a container containing electric discharge machining liquid; the wafer is provided with a first surface and a second surface which are opposite; the semiconductor wafer surface processing method comprises the following steps:

B. Providing electric energy to the discharge electrode to discharge the discharge electrode to the first surface of the wafer so as to change the surface morphology of the first surface of the wafer, wherein when the discharge electrode discharges the wafer, ultrasonic oscillation energy is also provided to perform surface roughness homogenization treatment on the wafer.

11. a semiconductor wafer surface processing method is suitable for an electric discharge machining device, and the electric discharge machining device comprises an electric discharge electrode and a container containing electric discharge machining liquid; the wafer is provided with a first surface and a second surface which are opposite; the semiconductor wafer surface processing method comprises the following steps:

Wherein, before step A, the method further comprises the following steps: the wafer is processed by high temperature heat treatment to release the stress and reduce the warpage.