CN115582919A

CN115582919A - Curved surface curved crystal preparation method

Info

Publication number: CN115582919A
Application number: CN202211173148.6A
Authority: CN
Inventors: 贡志锋; 张雪娜; 洪峰; 骆荣辉; 王翠焕; 张贝
Original assignee: Shenzhen Aisin Semiconductor Technology Co ltd
Current assignee: Shenzhen Aisin Semiconductor Technology Co ltd
Priority date: 2022-09-26
Filing date: 2022-09-26
Publication date: 2023-01-10

Abstract

The invention is suitable for the technical field of curved surface curved crystal preparation, and provides a curved surface curved crystal preparation method, which comprises the following steps: providing a female die and a wafer to be processed, wherein the female die is provided with a first curved surface matched with the curved surface of the curved crystal of the target curved surface; acquiring surface parameters of a target curved surface curved crystal, wherein the surface parameters comprise a surface radius and a surface radian; applying first pressure to two first edges of the wafer extending along a first direction to enable the first edges to be attached to the first curved surface until the first edges form a curved surface structure matched with the shape of corresponding areas in the first curved surface; a plurality of contact points distributed along the meridian direction are arranged between the first pressure and the wafer, and the first direction is a direction corresponding to the meridian direction of the curved crystal of the target curved surface; and applying a second pressure to the wafer to enable one surface of the wafer close to the first curved surface to be tightly attached to the first curved surface until the wafer forms a target curved surface structure matched with the first curved surface. The curved surface curved crystal preparation method provided by the invention can effectively improve the yield.

Description

Curved surface curved crystal preparation method

Technical Field

The invention belongs to the technical field of curved surface curved crystal preparation, and particularly relates to a curved surface curved crystal preparation method.

Background

The curved surface bending light splitting wafer (hereinafter referred to as curved surface bending crystal) is generally used in the field of X-ray, and can ensure that X-ray light injected into the wafer at a Bragg angle is converged after diffraction, and the diffraction light intensity is stronger than that of a plane wafer, so that the curved surface bending crystal can realize high light collection efficiency. But the curved surface curved crystal is generally formed by bending a single crystal. Since the single crystal is generally formed by using a brittle material such as mica, silicon, germanium, liF, graphite, and the like, a wafer is fragile when curved surface curved crystal is prepared, and the yield of curved surface curved crystal is low.

Therefore, it is necessary to develop a curved surface curved crystal preparation method capable of improving the yield of curved surface curved crystal.

Disclosure of Invention

The invention aims to provide a curved surface curved crystal preparation method, and aims to solve the technical problem of low yield of curved surface curved crystals in the prior art.

The invention is realized in such a way that a curved surface curved crystal preparation method comprises the following steps:

providing a female die and a wafer to be processed, wherein the female die is provided with a first curved surface matched with the curved surface of the target curved surface curved crystal;

acquiring surface parameters of the target curved surface curved crystal, wherein the surface parameters comprise a surface radius and a surface radian;

applying first pressure to two first edges of the wafer extending along a first direction to enable the first edges to be attached to the first curved surface until the first edges form a curved surface structure matched with the shape of corresponding areas in the first curved surface; a plurality of contact points distributed along a meridional direction are arranged between the first pressure and the wafer, and the first direction is a direction corresponding to the meridional direction of the curved crystal of the target curved surface;

and applying a second pressure to the wafer to enable one surface of the wafer close to the first curved surface to be tightly attached to the first curved surface until the wafer forms a target curved surface structure matched with the first curved surface.

In an alternative embodiment, said applying a second pressure to the entirety of the wafer comprises the steps of:

applying third pressure distributed at intervals on the whole stress surface of the wafer until the stress area of the wafer forms a curved surface structure matched with the shape of the corresponding area of the first curved surface;

applying fourth pressure to the whole stress surface of the wafer until the whole stress surface of the wafer is attached to the first curved surface to form the target curved surface structure; the contact area of the fourth pressure and the wafer is larger than or equal to the area of the force bearing surface of the wafer.

In an alternative embodiment, the first pressure applied to the two first edges of the wafer extending along the first direction and the third pressure applied to the whole force bearing surface of the wafer in a spaced mode are realized by a pre-pressing bending device;

the pre-pressing bending device comprises a female die and a male die, wherein the male die is provided with a plurality of deformation strips distributed at intervals in the first direction, the deformation strips are positioned on one side, away from the female die, of the wafer and can deform under the action of the first pressure and the third pressure so as to be changed from a first state matched with the initial shape of the wafer into a second state matched with the shape of the corresponding area of the first curved surface.

In an optional embodiment, the male die comprises a bracket, the deformation strip and force application modules corresponding to the deformation strip one by one; the force application module is arranged on the bracket, is positioned on one side of the deformation strip away from the female die and is used for applying reciprocating pressure to the corresponding deformation strip; each force application module comprises a plurality of force application single bodies which are arranged at intervals along the second direction; and two ends of the deformation strip in the second direction are respectively in sliding connection with the female die or the bracket along the second direction, and the second direction is a direction corresponding to the sagittal direction of the curved crystal of the target curved surface.

In an alternative embodiment, the force applying unit comprises a screw-threaded part in threaded connection with the bracket;

the pre-pressing bending device further comprises a first explosion-proof film, and the first explosion-proof film is used for being attached to the back face of the wafer;

and/or, the pre-pressing bending device further comprises a strain gauge, wherein the strain gauge is positioned between the female die and the male die and is used for being attached to the wafer so as to monitor the strain of the wafer.

In an alternative embodiment, the applying the fourth pressure to the whole force-bearing surface of the wafer is realized by a final pressure bending device;

the final-pressure bending device comprises a concave die, a pressing component, a second explosion-proof membrane and a protective membrane, wherein the pressing component is provided with a pressing part, the pressing part is located on one side, deviating from the first curved surface, of the wafer, the pressing part is used for applying pressure to the wafer towards the first curved surface, so that the wafer is close to the surface of the first curved surface and the first curved surface are tightly attached, the second explosion-proof membrane is used for being attached to the back surface of the wafer, and the protective membrane is used for being attached to the reflecting surface of the wafer.

In an optional embodiment, the pressing part comprises a pressing plate and a flexible member, wherein the flexible member is arranged on one surface of the pressing plate opposite to the first curved surface and is used for contacting with the wafer;

the flexible part is a soft rubber part; in an initial state, the area of a projection area of the flexible part on the first curved surface is smaller than that of the projection area of the pressure plate on the first curved surface; under pressure, the flexible member is able to fill the entire space between the platen and the wafer.

In an optional embodiment, the target curved crystal is a curved crystal, and the curved crystal preparation method further includes the following steps between the applying of the first pressure to the two first edges of the wafer extending in the first direction and the applying of the second pressure to the wafer:

and applying fifth pressure to two second edges of the wafer, which are oppositely arranged in the first direction, so that the second edges are attached to the first curved surface until the second edges form a curved surface structure matched with the shape of the corresponding area in the first curved surface.

In an alternative embodiment, said providing the female mold and the wafer to be processed comprises the following steps:

providing a concave die and a wafer to be cut;

acquiring arc length and central line length of each side of the curved crystal of the target curved surface;

obtaining processing parameters of the flat planar wafer after flattening treatment according to the length of each side arc and the length of the central line of the curved crystal of the target curved surface, wherein the processing parameters comprise the length of each side arc and the length of the central line of the planar wafer;

and cutting the wafer to be cut according to the processing parameters to obtain the wafer to be processed.

In an optional embodiment, the curved surface curved crystal preparation method further comprises the following steps:

providing a substrate;

and adhering the wafer with the target curved surface structure on the substrate by glue with the expansion coefficient close to that of the wafer.

Compared with the prior art, the invention has the technical effects that: the curved surface curved crystal preparation method provided by the embodiment of the invention changes the inherent way that a convex die and a concave die with fixed shapes directly press a wafer to realize the preparation of the target curved surface curved crystal in the traditional technology, and provides a novel curved surface curved crystal preparation method. The contact points distributed along the meridian direction are arranged between the first pressure and the wafer, so that point pressure of the convex die acting on the wafer is changed into linear pressure formed by a plurality of action points, stress on the local part of the wafer in the process of preparing single-curved-surface curved crystal can be effectively reduced, internal strain of the wafer is further reduced, the risk that the contact points of the wafer and the concave die are cracked in the processing process is reduced, and the yield of the target curved-surface curved crystal is improved. Meanwhile, the target curved surface curved crystal is finished by pressing twice, so that the internal strain of the wafer in the processing process can be further reduced, the risk of cracking of a plurality of contact points of the wafer and the female die in the processing process is reduced, and the yield of the target curved surface curved crystal is improved.

The curved surface curved crystal preparation method provided by the embodiment of the invention can realize the preparation of single-curved-surface curved crystal, double-curved-surface curved crystal and the like, is suitable for the preparation of curved surface curved crystal bent with small-radian bending, has high finished product rate of the prepared product, and can be widely applied to the fields of X-ray diffraction (XRD), X-ray reflection (XRR), micro-Fluorescence analysis (XRF), total-reflection Fluorescence analysis (TXRF) and the like. In addition, because the existing double-curved-surface curved crystal preparation technology is monopolized abroad and is high in price, the method provided by the embodiment of the invention is favorable for reducing the price of the double-curved-surface curved crystal and expanding the application of the double-curved-surface curved crystal in the field of X-ray.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention or in the description of the prior art will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram showing the optical path principle and characteristics of a hyperboloid curved crystal;

FIG. 2 is a schematic representation of the Rowland circle geometry;

FIG. 3 is a sagittal radius geometry diagram;

FIG. 4 is a schematic diagram showing the correspondence between the sizes of the wafer before and after flattening;

FIG. 5 is a schematic diagram showing the number and positions of contact points between the conventional male and female dies and the wafer when the wafer is subjected to a press bending operation using the conventional male and female dies;

FIG. 6 is a schematic step diagram of a curved-surface curved-crystal manufacturing method according to an embodiment of the present invention;

FIG. 7 is a schematic diagram illustrating a method for fabricating curved surfaces according to another embodiment of the present invention;

FIG. 8 is a schematic diagram illustrating a method for fabricating curved surfaces according to another embodiment of the present invention;

FIG. 9 is a schematic structural view of a female mold used in an embodiment of the present invention;

fig. 10 is a schematic perspective view of a pre-press bending apparatus used in an embodiment of the present invention;

FIG. 11 is a schematic side view of the pre-press bending apparatus shown in FIG. 10;

FIG. 12 isbase:Sub>A sectional structural view taken along the line A-A in FIG. 11;

FIG. 13 is an enlarged partial schematic view of A in FIG. 12;

FIG. 14 is a schematic perspective view of the pre-press bending apparatus shown in FIG. 1, except for the bracket and the force applying unit;

FIG. 15 is a schematic view of the structure of the wafer subjected to the operation of step S3 by the pre-press bending apparatus;

FIG. 16 is a schematic view showing the change in curvature of the wafer when the operation of step S3 is performed;

FIG. 17 is a schematic view showing the structure of the wafer subjected to the operation of step S5 by the pre-press bending apparatus;

FIG. 18 is a schematic view showing the change in the warpage of the wafer when the operation of step S5 is performed;

FIG. 19 is a schematic view showing the structure of the wafer subjected to the operation of step S41 by the pre-press bending apparatus;

FIG. 20 is a schematic view showing the change in curvature of the wafer when the operation of step S41 is performed;

FIG. 21 is a schematic perspective view of a final press bending apparatus used in an embodiment of the present invention;

FIG. 22 is a schematic side view of the final press bending apparatus of FIG. 21;

FIG. 23 is a cross-sectional view taken along line B-B of FIG. 22 showing the flexible member in an initial state;

fig. 24 is a cross-sectional structural view of the final press bending apparatus shown in fig. 23 after deformation of the flexible member.

Description of reference numerals:

100. a female die; 110. a first curved surface; 200. a wafer; 300. a pre-pressing bending device; 310. a male die; 311. deforming the strip; 312. a support; 313. a force application unit; 314. a strip hole; 320. a boss portion; 330. a strain gauge; 340. a first rupture membrane; 400. a final press bending device; 410. a pressing part; 411. pressing a plate; 412. a flexible member; 420. a second rupture disk; 430. a support frame; 440. a drive member; 450. a protective film; x', a first direction; y', a second direction.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are merely for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise explicitly stated or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as being permanently connected, detachably connected, or integral; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments.

The Curved surface Curved Crystal comprises a single Curved surface Curved Crystal and a Double Curved surface Curved Crystal (DCC), and the single Curved surface Curved Crystal comprises a half-focus (John-Type Curved Crystal) Curved Crystal and a full-focus (Johnson-Type Curved Crystal) Curved Crystal. The curved surface of the semi-focusing curved wafer is a cylindrical surface tangent to the Rowland circle, and the curved surface of the full-focusing curved wafer is a cylindrical surface with the curvature radius consistent with that of the Rowland circle.

Whereas the hyperboloid flexo is based on the Bragg diffraction principle. As shown in fig. 1, when the hyperboloid curved crystal is applied, X-rays from the radiation source S converge to a point I after being diffracted by the hyperboloid curved crystal. If one wants to get X-rays converging to a point, the crystal must have a curvature in two directions. Wherein points S, I lie on a rowland circle of radius R. The bending radius of the crystal in the horizontal direction (meridional direction) is R, and the bending radius R in the vertical direction (sagittal direction) is 2Rsin2 theta, wherein theta is a diffraction angle.

The curved crystal of hyperboloid needs to satisfy the geometrical structure of Roland circle (Roland), there is a Roland circle bending radius R in meridian plane (X-Y plane), there is another bending radius R (2 Rsin2 theta, where theta is Bragg diffraction angle) in sagittal plane (Y-Z plane), the curve in XY plane is Roland circle, the curve in YZ plane is the axis of the line connecting the light source point and the focus point, the whole is the rotating surface of radius R with the perpendicular line connecting the center of the wafer to the light source point and the focus point.

The curved crystal of hyperboloid has the following characteristics:

the hyperboloid curved crystal is placed between a ray source and a sample, geometrical optical relation of a Rowland circle is met, and X rays focused by the hyperboloid curved crystal can be focused to one point. If viewed at an out-of-focus position, an arc can be observed. The hyperboloid curved crystal is based on the Bragg diffraction principle, only allows X-rays meeting the requirement of specific wavelength to pass through, and therefore has a monochromatic effect. Meanwhile, the X-ray can be converged to one point, and the X-ray intensity is improved. This is two of the greatest advantages of hyperboloidal curved crystals.

The curved crystal is generally prepared by grinding and then bending, or bending and then grinding, or directly bending, but the directly bending method is generally only suitable for wafers with large radius, small wafer size and thin thickness, is not suitable for wafers with small radius and large size, and has low yield. Among them, the point that the double curved surface curved crystal processing is difficult is that the bending radius in the sagittal direction is only dozens of millimeters, and the curved surface is very fragile in the bending process. The prior documents mostly focus on the large-radian curved crystal manufacturing or the unidirectional curved crystal manufacturing. There is little literature on the processing of double curved surface curved crystals and no specific processing means is published. The existing commercialized products, what means that XOS company hyperboloid curved crystal adopted belongs to commercial secret, can't obtain.

Therefore, the embodiment of the invention provides a curved surface curved crystal preparation method which is suitable for preparing various curved surface curved crystals. Referring to fig. 6, in an embodiment of the present invention, a curved crystal manufacturing method is provided, including the following steps:

s1, providing a concave die and a wafer to be processed, wherein the concave die 100 is provided with a first curved surface 110 matched with the curved surface of the target curved surface curved crystal, as shown in FIG. 9. The target curved surface bent crystal referred to herein is a curved surface bent crystal obtained by processing according to the curved surface bent crystal preparation method provided in this example. The term "adaptive" means that the radius of the first curved surface 110 is equal to or slightly larger than the radius of the curved surface of the target curved surface curved crystal, and the size of the first curved surface 110 is generally larger than the size of the curved surface of the target curved surface curved crystal, so as to compensate the curvature deviation caused by the wafer to be processed and the attachment thereon.

Specifically, the target curved surface curved crystal can be a single curved surface curved crystal or a double curved surface curved crystal, and can be flexibly selected according to the use requirement. When the target curved-surface curved crystal is a single-curved-surface curved crystal, the first curved surface 110 is a single curved surface, and when the target curved-surface curved crystal is a double-curved-surface curved crystal, the first curved surface 110 is a double curved surface.

The female die 100 may be made of metal, plastic or other hard materials, and the first curved surface 110 may be made by machining, integral molding, or the like. The wafer to be processed is generally a planar wafer, and the material of the wafer may be any one of single crystals such as mica, silicon, germanium, liF, graphite, and the like, and may be determined according to the use environment of the target curved-surface curved crystal. Specifically, since the target curved surface curved crystal is generally used in the field of X-ray, when determining the material of the wafer to be processed, it is generally necessary to select an X-ray tube target material, such as Cu, rh, mo, au, etc., used in an X-ray system to which the target curved surface curved crystal is applied, determine the Ka-line wavelength of the target material after determining the target material, and then select a suitable wafer material according to the Ka-line wavelength. And since the thickness of the wafer to be processed is usually tens of microns and the efficiency of X-ray diffraction is high, the size and material of the wafer to be processed are determined according to the type and design requirements of the target curved crystal.

S2, obtaining surface parameters of the curved crystal of the target curved surface, wherein the surface parameters comprise a surface radius and a surface radian.

Specifically, the curved surface parameters may be set according to customization needs, or may be inferred from information such as the material and thickness of the target and the wafer. When the curved surface parameters need to be deduced according to the information of the target material, the thickness and the like of the wafer, an X-ray tube target material used in an X-ray system applying the target curved surface curved crystal is generally selected, the Ka-line wavelength of the target material can be determined after the target material is determined, then a proper wafer material, namely mica, silicon, germanium, liF, graphite and other single crystals are selected according to the Ka-line wavelength, the crystal plane direction and the diffraction angle theta are determined at the same time, then the curved surface radius of the target curved surface curved crystal is determined according to the diffraction angle theta, and then the curved surface radian is manually set according to the curved surface radius.

It should be noted that, because the target curved surface curved crystal may be a single-curved surface curved crystal or a double-curved surface curved crystal, and the curved surface radius and the curved surface radian of the single-curved surface curved crystal are only one, that is, the radius R of the rowland circle on the meridian plane and the curved surface radian on the meridian plane

The hyperboloid curved crystal has two curved surface radiuses and two curved surface radians, wherein the two curved surface radiuses are respectively a meridian plane Rowland circle radius R and a sagittal plane radius R, and the two curved surface radians are respectively curved surface radians on the meridian plane

And the radian of the curved surface on the sagittal plane

Therefore, when the curved crystal of the target curved surface is a single curved surface, the radius of the curved surface in the curved surface parameters is the radius R of the Rowland circle of the meridian plane, and the radian of the curved surface is the radian of the curved surface on the meridian plane

When the target curved surface curved crystal is a hyperboloid curved crystal, the curved surface radius in the curved surface parameters comprises a meridian plane Rowland circle radius R and a sagittal plane radius R; the radian of the curved surface comprises the radian of the curved surface on the meridian plane

And the radian of the curved surface on the sagittal plane

The camber is generally selected manually according to the material and thickness of the wafer and experience, and generally, the smaller the radius of the target curved surface, the smaller the wafer size, i.e. the smaller the camber, otherwise the wafer is easy to break. The determination of the radius of the curved surface generally needs to be based on some formulas, and for easy understanding, the target curved surface curved crystal is taken as a hyperboloid curved crystal as an example, and how to calculate the radius of the curved surface is illustrated.

(1) Calculating a Bragg angle of incidence θ

Selecting a target material as an Rh target, wherein the Ka line energy is as follows: e =20.22keV;

selecting a single crystal as Mica (Mica), wherein the interplanar spacing of the single crystal is as follows:

wherein

According to the energy wavelength formula: e = hc/λ;

bragg formula: n λ =2dsin θ, take n =1;

the available incident angle θ, θ = arcsin (λ/2 d) =5.2977 °.

(2) Calculating the radius R of the Rowland circle, i.e. the meridian radius

As shown in FIG. 2, the position S of the X-ray source, the light receiving point D of the curved surface and the corresponding node E of the Roland circle form a Δ SED. Specifically, Δ SED is a right triangle, and SD = ED × sin θ =2Rsin θ; i.e. F =2Rsin θ.

And the front focal length and the rear focal length are equal due to the symmetric relation SD = DP. According to the formula, the focal length F =249.73mm is artificially selected; the available rowland circle R = F/(2 sin θ) =1352.368mm.

(3) Calculating sagittal radius r

As shown in fig. 2, a position S where the X-ray source is located, and a light receiving point D of the curved surface curved crystal and a center G of the sagittal plane correspond to each other, form Δ SGD. Specifically, Δ SGD is a right triangle, and r = SD × sin θ =2Rsin2 θ, as shown in fig. 3. That is, sagittal direction r =2Rsin2 θ =23.058mm.

It can be understood that, when other targets are used, the Ka line energy in the above calculation is changed correspondingly, so that the calculation results of the above parameters are changed, which is the prior art and is not described herein in detail. Meanwhile, when the curved surface curved crystal is a single curved surface curved crystal, the calculation mode is similar to the method, but the sagittal radius r is not required to be calculated.

And S3, applying first pressure to the two first edges of the wafer extending along the first direction X' to enable the first edges to be attached to the first curved surface until the first edges form a curved surface structure matched with the shape of the corresponding area in the first curved surface. The first pressure and the wafer have a plurality of contact points distributed along a meridional direction, and the first direction X' is a direction corresponding to the meridional direction of the curved crystal of the target surface. The first direction X' referred to herein as corresponding to the meridional direction of the curved-surface curved crystal means a linear direction in which the extending direction of the planar wafer substantially coincides with the meridional direction of the curved-surface curved crystal in the initial state.

In particular, this step can be carried out by means of one or more male dies in the form of a sheet or block on the side of the wafer facing away from the female die, as shown in fig. 16. Each punch may be in point or face contact with the wafer 200. When each convex die is required to be in surface contact with the wafer 200, the deformation can be realized by adopting a flexible part, so that the contact surface of the convex die and the wafer 200 can be deformed, and the surface of the convex die, which is used for being in contact with the wafer 200 in the deformation process of the curved surface of the wafer 200, can be always attached to the wafer 200. This step may be performed slowly and continuously over a period of time, or may be performed repeatedly and intermittently over a period of time, depending on the conditions of the wafer 200 during processing (e.g., the amount of internal strain).

And S4, as shown in the graph 20, applying a second pressure to the wafer to enable one surface, close to the first curved surface, of the wafer to be tightly attached to the first curved surface until the wafer forms a target curved surface structure matched with the first curved surface.

Specifically, this step can be implemented with the aid of a male die in the prior art, and other male dies capable of implementing the above functions can also be designed by themselves. The above-mentioned pressing process may be performed slowly and continuously over a period of time, or may be performed repeatedly and intermittently over a period of time, and may be performed by a group of molds, or may be performed by a plurality of molds, which may be determined according to the conditions of the wafer during the processing (such as the magnitude of internal strain).

The working principle of the curved surface curved crystal preparation method provided by the embodiment of the invention is as follows:

the conventional curved crystal is formed by pressing a concave die and a convex die which are arranged up and down, and by adopting the technology, in the operation process, as shown in fig. 5, the convex die has only 1 contact point with the wafer 200, and the concave die 100 has 4 contact points with the wafer 200. The 4 contact points where the die 100 contacts the wafer 200 easily cause a problem of chipping of the wafer 200 due to the stress concentration problem.

In order to solve the above problems, the inventors have studied the curved-surface curved crystal manufacturing method provided in the embodiment of the present invention again, and found that when the target curved-surface curved crystal is a single-curved-surface curved crystal, the target curved-surface curved crystal has only the meridional-direction bending radius R, and when the target curved-surface curved crystal is a double-curved-surface curved crystal, the target curved-surface curved crystal has both the meridional-direction bending radius R and the sagittal-direction bending radius R, but the meridional-direction bending radius R is generally large, the bending stress is small, and the sagittal-plane bending radii R are 2Rsin2 θ, sin2 θ < <1, that is, the sagittal-plane bending radii are much smaller, and the single-crystal sheet is very likely to be broken during the bending process.

When the wafer 200 is subjected to the bending operation, first pressure is applied to two first edges of the wafer 200 extending along the first direction X' to make the first edges adhere to the first curved surface 110 until the first edges form a curved surface structure with a shape matching with a corresponding region in the first curved surface 110, and at this time, other regions of the wafer 200 are also bent along with the first edges to form a bent wafer shape, as shown in fig. 16. In the above operation process, a plurality of contact points distributed along the meridian direction are provided between the first pressure and the wafer 200, so that the point pressure of the convex mold acting on the wafer 200 is changed into the line pressure formed by a plurality of acting points, and further, the stress locally applied to the wafer 200 is reduced, and further, the internal strain of the wafer 200 is reduced.

However, after the above operations, the central region of the wafer 200 may not be attached to the first curved surface 110, and then the wafer 200 is integrally pressed by a common convex mold or other devices, so that the central region, the central line, etc. of the wafer 200 may also be closely attached to the first curved surface 110, that is, the surface of the wafer 200, which is used for contacting with the first curved surface 110, is attached to the first curved surface 110 until the wafer 200 forms a curved surface structure adapted to the first curved surface 110.

In summary, the curved-surface curved crystal manufacturing method provided by the embodiment of the present invention changes the inherent way of directly pressing the wafer 200 through the male mold and the female mold having fixed shapes in the conventional technology to realize the manufacturing of the target curved-surface curved crystal, and provides a new curved-surface curved crystal manufacturing method, when manufacturing, first pressure is applied to two first edges extending along the first direction X' of the wafer 200, so that the corresponding edges (i.e., the first edges) of the wafer 200 are attached to the first curved surface 110, so as to manufacture a single-curved-surface curved crystal, and then the entire wafer 200 is pressed, so as to manufacture the final target curved-surface curved crystal. A plurality of contact points distributed along the meridian direction are arranged between the first pressure and the wafer 200, so that the point pressure of the convex mold acting on the wafer 200 is changed into the linear pressure formed by a plurality of action points, the stress on the local part of the wafer 200 in the process of preparing the single-curved-surface curved crystal can be effectively reduced, the internal strain of the wafer 200 is further reduced, the risk of cracking of the contact points of the wafer 200 and the concave mold 100 in the processing process is reduced, and the yield of the target curved-surface curved crystal is improved. Meanwhile, the target curved surface curved crystal is finished by pressing twice, so that the internal strain of the wafer 200 in the processing process can be further reduced, the risk of cracking of a plurality of contact points of the wafer 200 and the concave die 100 in the processing process is reduced, and the yield of the target curved surface curved crystal is improved.

The curved surface curved crystal preparation method provided by the embodiment of the invention can realize the preparation of single curved surface curved crystal, double curved surface curved crystal and the like, is suitable for the preparation of curved surface curved crystal bent with small curvature, has high finished product rate, and can be widely applied to the fields of X-ray diffraction (XRD), X-ray reflection (XRR), micro-Fluorescence analysis (XRF), total-reflection X-ray Fluorescence spectroscopy (TXRF) and the like. In addition, because the existing double-curved-surface curved crystal preparation technology is monopolized abroad and is high in price, the method provided by the embodiment of the invention is favorable for reducing the price of the double-curved-surface curved crystal and expanding the application of the double-curved-surface curved crystal in the field of X-ray.

The step S4 may be implemented by one operation of one mold, or may be implemented by multiple operations of multiple molds. Wherein, when multiple operations are performed with multiple dies, the risk of chipping of the wafer 200 during processing can be further reduced.

As shown in fig. 7, in an alternative embodiment, the step S4 includes the following steps:

s41, applying third pressure distributed at intervals to the whole stress surface of the wafer until the stress area of the wafer forms a curved surface structure matched with the shape of the corresponding area of the first curved surface.

Specifically, in this step, the contact area of the single third pressure and the wafer is smaller than the area of the force-bearing surface of the wafer, and the sum of the contact areas of all the third pressures and the wafer is smaller than the area of the force-bearing surface of the wafer. This step can be carried out by means of a plurality of sheet-like or block-like male moulds on the side of the wafer facing away from the female mould. The male die can be provided with continuous flexible parts extending along the meridian direction or flexible parts distributed at intervals along the meridian direction, and can also be provided with continuous or distributed flexible parts extending along the direction perpendicular to the meridian direction or flexible parts arranged in other modes, so that the male die can be always attached to the wafer when third pressure is applied to the wafer; other structures, such as a convex structure similar to a common convex structure, can be adopted as long as the above functions can be realized, and the structure is not limited only here. This step may be performed slowly and continuously over a period of time, or may be performed repeatedly and intermittently over a period of time, depending on the conditions of the wafer during processing (e.g., the amount of internal strain).

And S42, applying fourth pressure to the whole stress surface of the wafer until the whole stress surface of the wafer is attached to the first curved surface to form a target curved surface structure. The contact area of the fourth pressure and the wafer is larger than or equal to the area of the stress surface of the wafer.

Specifically, the step can be realized by means of the male die in the prior art, and other male dies capable of realizing the functions can also be designed by self. The pressing process may be performed continuously and slowly over a period of time, or may be performed intermittently and repeatedly over a period of time, depending on the conditions of the wafer during processing (e.g., the amount of internal strain).

By adopting the steps provided by the embodiment, the step S4 is realized by dividing into two steps, and the third pressures are distributed at intervals, so that the internal strain of the wafer in the operation process of each step can be effectively reduced, and the risk of the wafer cracking can be effectively reduced.

The steps S3 and S41 can be implemented in various manners, and for convenience of operation, in an alternative embodiment, the steps S3 and S41 are implemented by a pre-press bending device, as shown in fig. 15, 16, 19 and 20. Therefore, the two steps adjacent to each other in the operation sequence can be realized by the same device, and the processing efficiency can be improved.

As shown in fig. 10 to 14, the pre-press bending apparatus 300 includes a female die 100 and a male die 310, the male die 310 has a plurality of deformation strips 311 spaced along the first direction, the deformation strips 311 are located on a side of the wafer 200 facing away from the female die 100 and can be deformed under the action of a first pressure and a third pressure to change from a first state matching with the original shape of the wafer 200 to a second state matching with the shape of the corresponding region of the first curved surface 110.

Since the curved crystal of the target curved surface may be a single curved crystal or a double curved single crystal, the first curved surface 110 may be a single curved surface or a double curved surface, when the first curved surface 110 is a double curved surface, the first state and the second state of the second curved surface are also generally double curved surfaces, and at this time, different regions of the second curved surface have different bending degrees, and at this time, if the surface of the convex mold 310, which is in contact with the wafer 200, adopts an integrated structure, it is difficult to deform into a curved surface adapted to the first curved surface 110.

To this end, the inventor has developed a male mold 310 provided in the present embodiment, wherein the male mold 310 has a plurality of deformation strips 311 spaced along the first direction. Specifically, the deformation strip 311 in this embodiment is a strip-shaped structure that has certain elasticity and can be bent, and can be a metal strip, a plastic strip, an adhesive tape, etc., and can be an integrated structure, such as a metal strip, a plastic strip, an adhesive tape, etc., and can also be a multilayer structure, such as a metal strip and an adhesive tape, a plastic strip, an adhesive tape, etc. stacked in layers, and can be flexibly selected according to use requirements. In addition, the deformation strip 311 in this embodiment can deform under the action of the first pressure and the third pressure to change from the first state adapted to the initial shape of the wafer 200 to the second state adapted to the shape of the corresponding region of the first curved surface 110, so as to press the wafer 200, and in the pressing process, the deformation strip 311 can be always tightly attached to the wafer 200 to realize surface contact with the wafer 200, and the process can be slowly performed to improve the stress distribution of the wafer 200, so as to reduce the internal strain of the wafer 200 to a smaller extent, thereby effectively reducing the risk of the wafer 200 cracking in the processing process. Meanwhile, the arrangement of the plurality of deformation strips 311 can realize the control of the bending radius of the wafer 200 in two directions, and not only can be matched with the female die 100 to prepare regular single-curved-surface curved crystals and regular double-curved-surface curved crystals, but also can prepare curved-surface curved crystals with asymmetric arc surfaces.

The pre-pressing bending device 300 provided by the embodiment utilizes a deformation self-adaptive technology, effectively improves the contact area between the male die 310 and the wafer 200, reduces the risk of stress concentration of the wafer 200 in the processing process, can effectively improve the yield, is suitable for preparing most curved crystals, especially for preparing hyperbolic curved crystals with small bending radius, and is simple to adjust and convenient to operate.

As shown in fig. 12 and 13, in an alternative embodiment, the male mold 310 includes a support 312, a deformation strip 311, and force application modules corresponding to the deformation strip 311 one by one. The force application module is installed on the bracket 312 and located on one side of the deformation strip 311 away from the female die 100, and is used for applying reciprocating pressure to the corresponding deformation strip 311. Each force application module comprises a plurality of force application single bodies 313 which are arranged at intervals along the second direction Y'. Two ends of the deformation bar 311 in the second direction Y 'are slidably connected to the female die 100 or the bracket 312, respectively, along the second direction Y'. The second direction Y' is a direction corresponding to the sagittal direction of the target curved surface curved crystal. The second direction Y' referred to herein corresponds to the sagittal direction of the curved crystal of the target curved surface, and means a linear direction in which the extending direction of the planar wafer substantially coincides with the sagittal direction of the curved crystal of the target curved surface in the initial state.

Specifically, the biasing members 313 may have the same or different structures. With this configuration, when the operation of step S3 is performed, the force applying units 313 corresponding to the two first edges of the wafer 200 extending in the first direction X' are selected, the amount of pressing the wafer 200 is adjusted, the two first edges of the wafer 200 will gradually adhere to the first curved surface 110 with the adjustment of the pre-pressing amount, and the plurality of pressing portions 410 are in contact with the wafer 200 during the whole process, so that the contact stress is small. Meanwhile, the structure is adopted to facilitate the smooth proceeding of the step S41, which is particularly characterized in that when the step S41 is performed, the pressing amount of all the force application monomers 313 on the wafer 200 is adjusted, so that different areas of the wafer 200 can be attached to the first curved surface 110, and because the force application monomers 313 are independent of each other, different areas of the deformation strip 311 can be deformed to different degrees as required, so that the wafer 200 can be adapted to the first curved surfaces 110 of different shapes, and compared with the single force application monomer 313 adopted by each force application module, the possibility of complex deformation of a deformation part can be further improved, and the preparation requirements of curved crystals of different curved surfaces can be met.

In an alternative embodiment, the force application unit 313 includes a threaded member that is threadedly coupled to the bracket 312. Specifically, the screw may be a screw, a threaded rod, or a combination of a screw, a threaded rod, and other components, and may be flexibly selected according to a use requirement, which is not limited herein. The force applying unit 313 has the structure provided by the embodiment, and is simple in structure, convenient to adjust and low in cost.

In one embodiment, the threaded connection is provided by a fine-pitch screw or a micro-head. By adjusting its depth, the arc of the deformation bar 311 can be changed. The double-curved surface can be formed by a plurality of screw elements and a plurality of deformation strips 311.

In order to further reduce the risk of breaking the wafer 200 when the pre-press bending apparatus 300 provided in the above embodiments is used for operation, as shown in fig. 13, in an alternative embodiment, the pre-press bending apparatus 300 further includes a first explosion-proof film 340, and the first explosion-proof film 340 is used for being attached to the back surface of the wafer 200, so as to provide support for the wafer 200, improve the toughness of the wafer 200, and reduce the risk of local fracture.

Specifically, the wafer 200 has a reflection surface and a surface opposite to the reflection surface, and the reflection surface is generally referred to as a front surface and the surface opposite to the front surface is referred to as a back surface. In fig. 13, the upper surface of the wafer 200 is a reflection surface, and the first explosion-proof film 340 is attached to the lower surface of the wafer 200, i.e. the surface of the wafer 200 contacting the first curved surface 110. The first explosion-proof film 340 in this embodiment may be a tough film made of a polymer material, and the surface of the tough film is coated with glue and adhered to the wafer 200.

As shown in fig. 13, in an alternative embodiment, the pre-press bending apparatus 300 further includes a strain gauge 330. The strain gauge 330 is disposed between the female mold 100 and the male mold 310, and is attached to an upper surface or a lower surface of the wafer 200, and monitors the strain of the wafer 200. When in use, the strain gauge 330 may be attached to the wafer 200, and then the wafer 200 is placed on the cavity die 100. The strain gauge 330 in this embodiment may be a wireless strain gauge or a wired strain gauge. When the strain gauge 330 is in a wired structure, after the wafer 200 is placed on the die 100, a data line connected to the strain gauge 330 needs to be connected to an external data processing device (e.g., a computer) through a gap between the deformation strips 311; when the strain gauge 330 is in a wireless structure, the strain gauge 330 is connected to an external data processing device (e.g., a computer) in a wireless transmission manner, so that the connection is convenient and fast, and there is no need to worry about adverse effects on the data lines during the bending process of the wafer 200 or adverse effects on the bending operation of the wafer 200 due to the existence of the data lines.

It should be noted that, when the pre-press bending apparatus 300 is provided with the first explosion-proof film 340 and the strain gauge 330 at the same time, the two films are required to be separately disposed on two sides of the wafer 200, and at this time, since the first explosion-proof film 340 is generally attached to the back surface of the wafer 200, the strain gauge 330 is attached to the reflection surface of the wafer 200. When the curved-surface curved-wafer manufacturing apparatus is provided with only the strain gauge 330, the strain gauge 330 is generally attached to the back surface of the wafer 200 in order to prevent the reflective surface of the wafer 200 from being damaged by the attachment of the strain gauge 330. Since the strain gauge 330 is attached to the reflective surface, the strain gauge 330 needs to be removed after use, and the removal of the strain gauge 330 may affect the normal use of the wafer 200, this solution is only suitable for use when the pressure is applied to the wafer 200 at each stage in the curved-surface wafer manufacturing process, and is not suitable for use when the target curved surface is manufactured.

By adopting the structure, when the wafer to be processed is processed, the strain of the wafer 200 can be measured in real time through the strain gauge 330, and the internal stress of the wafer 200 is calculated by means of an external data processing device, so that an operator can adjust the pressure applied to a deformation part through the monitoring result, the phenomenon that the internal stress of the wafer 200 exceeds the yield strength and is cracked due to overlarge pressure is prevented, the yield is further improved, and the strain gauge 330 can be eliminated after the bending process is determined. The pre-pressing bending device 300 provided by the embodiment adopts a stress-strain adaptive technology and combines a stress analysis technology to ensure that the internal stress of the wafer 200 is monitored in the measuring process, and the pre-pressing amount applied to the deformation part can be continuously adjusted according to the monitoring result during use so as to realize the pre-pressing of the wafer 200, thereby greatly reducing the probability of the curved-surface bent crystal cracking in the bending process.

As shown in fig. 13, in an alternative embodiment, the strain gauge 330 is attached to a surface of the wafer 200 away from the first curved surface 110, so as to prevent the surface of the wafer 200 contacting the first curved surface 110 from adversely affecting the first curved surface 110.

On the basis of the above embodiment, in order to further improve the stability of the force applying member for applying the pressure to the deformation member, as shown in fig. 13, in an alternative embodiment, the screw member includes a shoulder screw threadedly connected to the bracket 312, and a constant force elastic member sleeved on one end of the shoulder screw near the female die 100. Specifically, the constant-force elastic part is sleeved on the shaft shoulder screw and is concentric with the shaft shoulder screw, and the shaft shoulder on the shaft shoulder screw can block the constant-force elastic part from moving upwards, so that when the shaft shoulder screw is rotated downwards, the constant-force elastic part is extruded, and the other end of the constant-force elastic part is contacted with the deformation part and pushes the deformation part to protrude downwards. Through the shoulder screw, not only the profiling of the curved surface is realized, but also the wafer 200 is always in a stressed state due to the action of the constant-force elastic piece, which is beneficial to the continuous deformation until being attached to the first curved surface 110.

The sliding connection between the deformation strip 311 and its supporting component (the die 100 or the bracket 312) has various ways, for example, a sliding groove is provided on the deformation strip 311, and a sliding rail or a sliding block in sliding fit with the supporting component is provided on the deformation strip 311; or the deformation bar 311 is provided with a sliding rail or a sliding block, and the supporting member is provided with a sliding groove in sliding fit with the sliding rail or the sliding block, but other forms can also be adopted.

As shown in fig. 12 and 14, in an alternative embodiment, the female die 100 or the support 312 is respectively provided with a plurality of protrusions 320 corresponding to the plurality of deformation strips 311 one to one on both sides of the second direction Y'. Both ends of each deformation strip 311 are opened with a long hole 314 extending along the second direction Y'. The elongated hole 314 is used for the corresponding boss 320 to pass through and slide, so as to realize the sliding connection of the deformation strip 311 with the female die 100 or the bracket 312.

In the initial state, the deformation strip 311 is in a straight state or an initial bent state, in which the distance between the elongated holes 314 at both ends of the same deformation strip 311 in the horizontal direction is long, and the protrusion 320 is generally located in a first region of the elongated hole 314, where the first region is a half region of the elongated hole 314 close to the center of the deformation strip 311. When the deformation strip 311 is pressed, the bending degree of the deformation strip is gradually increased, and the distance between the elongated holes 314 at the two ends of the same deformation strip 311 in the horizontal direction is gradually shortened, during which the protrusions 320 are always located in the corresponding elongated holes 314, so as to limit the two ends of the deformation strip 311 to stretch in the second direction Y'.

By adopting the structure provided by the embodiment, the sliding connection between the deformation strip 311 and the concave die 100 or the bracket 312 is realized, and the deformation strip 311 is convenient to mount.

The protrusion 320 in the above embodiments may be integrally formed on the die 100 or the bracket 312, or may be detachably fixed to the die 100 or the bracket 312. When the convex part 320 is integrally formed on the female die 100 or the bracket 312, the structure is stable and the assembly is convenient; when the projection 320 is detachably mounted to the die 100 or the holder 312, maintenance and replacement are facilitated.

Step S42 can be implemented in various ways, and in order to reduce the risk of wafer chipping during the operation, in an alternative embodiment, step S42 can be implemented by a final-press bending apparatus.

As shown in fig. 21 to 24, the final-pressure bending apparatus 400 includes a female mold 100, a pressing assembly, a second rupture disk 420, and a protective membrane 450. The pressing assembly has a pressing part 410. The pressing part 410 is located at a side of the wafer 200 facing away from the first curved surface 110. The pressing portion 410 is used for applying a pressure to the wafer 200 towards the first curved surface 110, so that the surface of the wafer 200 close to the first curved surface 110 is tightly attached to the first curved surface 110. The second explosion-proof film 420 is attached to the back surface of the wafer 200, and the protective film 450 is attached to the reflective surface of the wafer 200.

The pressing assembly in this embodiment may be a manual assembly, which is driven by a hand or other foreign object to apply pressure to the wafer 200; alternatively, an electrical component, such as a press block having a driving member 440 such as an air cylinder or a hydraulic cylinder, may be used to automatically apply pressure to the wafer 200 by an electrical, pneumatic, or other system. The surface of the pressing portion 410 contacting the wafer 200 may have a flexible layer, or the shape of the pressing portion is adapted to the first curved surface 110, so that when the pressing portion is driven by pressure to cooperate with the first curved surface 110 to clamp the wafer 200, the surface of the wafer 200 close to the first curved surface 110 is tightly attached to the first curved surface 110, and the curved surface of the pressed wafer 200 is adapted to the first curved surface 110. The fitting here means that the curved surface shape and radius of the wafer 200 are identical or substantially identical to the curved surface shape and radius of the first curved surface 110.

The final press bending apparatus 400 used in the present embodiment uses the following principle:

when the anti-explosion device is used, the second anti-explosion film 420 is attached to the back surface of the wafer 200 to be processed, the protective film 450 is attached to the reflecting surface of the wafer 200 to be processed, then the wafer 200 to be processed is placed between the first curved surface 110 and the pressing part 410, and the pressing part 410 is controlled to apply pressure towards the first curved surface 110 to the wafer 200, so that the surface, close to the first curved surface 110, of the wafer 200 is tightly attached to the first curved surface 110 until the wafer 200 is shaped.

During this period, the second explosion-proof membrane 420 is attached to the wafer 200, so that the risk of the wafer 200 being broken during the pressing process can be effectively reduced. Meanwhile, in order to further reduce the risk of the wafer 200 breaking during the above process, the wafer 200 to be processed used in the present embodiment may be the wafer 200 that has been subjected to pressing deformation by other bending devices. Thus, the wafer 200 itself placed between the first curved surface 110 and the pressing portion 410 has a curved surface shape corresponding to the first curved surface 110, and only a small amount of deformation is required to form a shape adapted to the first curved surface 110, which further reduces the risk of cracking. In this embodiment, the protective film does not have adhesive or is torn off without leaving a primer film. After the wafer 200 is prepared, the protective film 450 is torn off, so that the reflective surface of the wafer 200 can be effectively protected from being scratched.

To further reduce the risk of the wafer 200 being broken when the pressure applying part 410 applies pressure to the wafer 200, referring to fig. 23, in an alternative embodiment, the pressure applying part 410 includes a pressure plate 411 and a flexible member 412, and the flexible member 412 is installed on a side of the pressure plate 411 opposite to the first curved surface 110 and is used for contacting the wafer 200.

In an alternative embodiment, the flexible member 412 is a soft rubber member. As shown in fig. 23, in the initial state, the area of the projection area of the flexible member 412 on the first curved surface 110 is smaller than the area of the projection area of the pressing plate 411 on the first curved surface 110; as shown in fig. 24, the flexible member 412 can fill the entire space between the pressing plate 411 and the first curved surface 110 under pressure.

In this embodiment, the soft rubber member may be made of silica gel having good fluidity, or may be an air bag filled with water or gas. The soft rubber part has good filling effect. In use, when the pressing portion 410 receives pressure, the pressing plate 411 moves towards the first curved surface 110, and meanwhile, the soft rubber gradually contacts with the wafer 200 and is extruded and deformed, and as the soft rubber is continuously stressed and deformed, the whole space surrounded by the pressing plate 411 and the wafer 200 is gradually filled, and uniform pressure is applied to the wafer 200, so that the wafer 200 is completely attached to the first curved surface 110. With this configuration, different areas of the wafer 200 are uniformly stressed, thereby reducing the risk of chipping.

The pressing assembly has various implementations, and as shown in fig. 21 to 24, in an alternative embodiment, the pressing assembly includes a supporting frame 430, a driving member 440, and a pressing portion 410. The driving member 440 is mounted on the driving member 440 of the supporting frame 430 and is located on a side of the pressing portion 410 away from the first curved surface 110. The driving member 440 has a telescopic function or can move relative to the supporting frame 430 for applying a pushing force to the pressing portion 410 toward the first curved surface 110. In this embodiment, the supporting frame 430 is used to support the driving element 440, and limit the driving element 440 to a side of the pressing portion 410 away from the first curved surface 110, and the shape of the supporting frame may be flexibly set according to the use requirement, for example, the supporting frame may adopt an L-shaped structure, a U-shaped structure, and the like, and is not limited herein. The driving member 440 may be a manual member driven by hand or other objects during use, or an electric member such as an air cylinder, an electric cylinder, a hydraulic cylinder, etc. In addition, the driving member 440 may be connected to or disconnected from the pressing portion 410, and when the driving member 440 is connected to the pressing portion 410, it may not only apply a pushing force to the pressing portion 410 towards the first curved surface 110, but also apply a pulling force to the pressing portion 410, which may be flexibly selected according to the use requirement, and is not limited herein.

With the structure provided by this embodiment, the entire structure of the pressing assembly is simple, and it is convenient to apply pressure to the pressing portion 410, so as to facilitate the smooth processing of the wafer 200.

In order to further reduce the risk of the wafer cracking during the manufacturing process when the target curved-surface curved crystal is the double-curved-surface curved crystal due to different bending degrees of the single-curved-surface curved crystal and the double-curved-surface curved crystal, as shown in fig. 8, in an alternative embodiment, the target curved-surface curved crystal is the double-curved-surface curved crystal, and the curved-surface curved crystal manufacturing method further includes the following steps between step S3 and step S4:

and S5, applying fifth pressure to two second edges of the wafer, which are oppositely arranged in the first direction, so that the second edges are attached to the first curved surface until the second edges form a curved surface structure matched with the shape of the corresponding area in the first curved surface. Wherein the fifth pressure has a plurality of contact points distributed along the second direction Y' with the wafer.

In particular, this step can be performed by the pre-press bending device described above (as shown in fig. 17 and 18), or by one or more other male dies in the form of a sheet or block located on the side of the wafer facing away from the female die. Each punch may be in point or face contact with the wafer. When each terrace die is in contact with the wafer surface, the flexible part capable of realizing deformation can be adopted for realizing, so that the contact surface of the terrace die and the wafer can be deformed, and the surface of the wafer, which is used for being in contact with the wafer in the convex die in the deformation process, can be always attached to the wafer. This step may be performed slowly and continuously over a period of time, or may be performed repeatedly and intermittently over a period of time, depending on the conditions of the wafer during processing (e.g., the amount of internal strain).

The curved surface curved crystal preparation method provided by the embodiment is suitable for preparing a curved surface curved crystal, as shown in fig. 15 to fig. 20, during preparation, step S3 may be performed first to realize single-side pre-pressing in the meridional direction, step S5 is performed to realize single-side pre-pressing in the sagittal direction, after the two steps are completed, the central position of the wafer often cannot contact with the lowest position of the first curved surface, and finally, step S4 is performed to realize comprehensive pre-pressing, so that the deformation of the wafer in step S4 can be effectively reduced, the risk of wafer cracking in the step S4 is further reduced, and the yield of products is improved.

The wafer to be processed can be obtained by purchase or can be prepared by self-processing. When self-processing, it can be prepared in the following manner. Illustratively, the above-mentioned providing of the female mold and the wafer to be processed comprises the steps of:

s11, providing a concave die and a wafer to be cut.

In particular, the wafer to be cut is generally a planar wafer having dimensions larger than the wafer to be processed.

And S12, obtaining the arc length and the central line length of each side of the curved crystal of the target curved surface.

Specifically, the target curved surface curved crystal is generally a regular pattern, and after the curved surface radius and the curved surface radian of the target curved surface curved crystal are determined, the arc length and the center line length of each side of the target curved surface curved crystal can be calculated, and can also be set according to customization requirements. As shown in fig. 4, two long sides a, which are oppositely arranged in the curved crystal of the target curved surface, have the same arc length, two short sides b have the same arc length, and two central lines (a 'and b') are provided. The length of each side arc and the length of the center line can be calculated by the radius of the curved surface, the radian of the curved surface and the known technology, and are not described herein again.

And S13, obtaining processing parameters of the flat wafer after flattening treatment according to the length of each side arc and the length of the central line of the curved crystal of the target curved surface, wherein the processing parameters comprise the length of each side arc and the length of the central line of the flat wafer.

Specifically, as shown in fig. 4, each side arc length of the target curved-surface bent crystal is the side arc length of the planar wafer, and the center line length of the target curved-surface bent crystal is the center line length of the planar wafer.

And S14, cutting the wafer to be cut according to the processing parameters to obtain the wafer to be processed.

Because the target curved surface curved crystal is a curved surface structure, and the wafer used in processing is generally a plane wafer, in order to improve the yield of the curved crystal, in the actual processing process, the curved surface of the target curved surface curved crystal is selected to be flattened (which can be completed by simulation software), and then the corresponding processing parameters of the wafer are obtained. The processing parameters include the degree of curvature, arc length, etc. of each side of the flattened wafer. In some embodiments, as shown in FIG. 4, the wafer may be seen after it is flattened to be actually concave on both sides and convex up and down. In other embodiments, the wafer may have other shapes after being flattened, and the shape is not limited herein.

By adopting the structure, compared with the to-be-processed wafer with a rectangular structure, the edge shape of the to-be-processed wafer can be matched with the side length shape of the curved crystal of the target curved surface, and the risk of cracking of the wafer in the subsequent processing process can be effectively reduced.

In other embodiments, the curved surface curved crystal preparation method further comprises the following steps:

s6, providing a substrate.

The substrate can be made of plastic materials, metal materials and the like, generally has a supporting surface matched with the first curved surface, and is used for bearing the processed curved crystal of the target curved surface.

And S7, bonding the wafer with the target curved surface structure on the substrate through glue with the expansion coefficient close to that of the wafer.

The target curved crystal and the substrate are fixed by the expansion coefficient close to glue, so that the risk of cracking of the target curved crystal caused by temperature change in the using process can be effectively reduced. When the curved-surface wafer bending device is used, the movement and position adjustment of the curved-surface curved wafer can be realized through the substrate, and the risk that the service life and the service performance of the wafer are influenced by directly touching the wafer can be effectively reduced.

In other embodiments, the curved surface curved crystal preparation method further includes the following steps after the wafer forms the target curved surface structure matched with the first curved surface (i.e. step S4):

and S8, detecting whether the target curved surface structure is consistent with the curved surface of the curved crystal of the target curved surface.

The step can be detected by a female die and a male die which have curved surface structures consistent with the curved surface of the curved crystal of the target curved surface. During detection, the wafer generated in the step S4 is placed between the female die and the male die, pressure is applied to the upper die, so that the wafer is as close as possible to the lower die under the combined action of gravity or gravity and external pressure, when the upper die moves to the lowest position, whether the distance between the two dies is the thickness of the wafer is determined, if not, and if the difference is greater than the error value, the target curved surface structure formed by the wafer formed in the steps is unqualified, and if or within the error value, the target curved surface structure formed by the wafer formed in the steps is qualified.

Whether the curved surface structure of the product meets the requirements or not can be verified through the step S8, so that problems can be found in time when the product is unqualified, unreasonable places in the steps are adjusted, and the qualification rate of the finished product is finally guaranteed.

When step S6 and step S7 are present, step S8 is generally performed before step S6 and step S7.

In a specific embodiment, the curved surface curved crystal is a hyperboloid curved crystal, and the curved surface curved crystal preparation method includes step S1, step S2, step S3, step S4 and step S5, where step S4 includes steps S41 and S42, and steps S3, S41 and S5 are implemented by using a pre-press bending device as shown in the figure, and step S4 is implemented by using a final-press bending device.

When a double-curved-surface curved crystal is prepared, as shown in fig. 15, the pressing amount of the force application monomer (namely, the force application monomer is shown by a dashed line in the figure) located at the first edge of the wafer to the deformation strip is increased, and the first edge of the wafer (namely, the edge extending in the meridian direction) is pre-pressed until the first edge of the wafer and the first curved surface are attached to each other to realize line contact, as shown in fig. 16; then, as shown in fig. 17, the pressing amount of the force applying unit located at the second edge of the wafer (i.e., the force applying unit is shown by a dashed frame in the figure) on the deformation bar is increased, the second edge of the wafer is pre-pressed until the four edges of the wafer are all attached to the first curved surface, and as shown in fig. 18, the pressing amount of the remaining force applying unit (i.e., the force applying unit is shown by a dashed frame in the figure) on the deformation bar is finally increased, so that the remaining region of the wafer is pre-pressed until the center line and the central region of the wafer are both attached to the first curved surface, as shown in fig. 20.

And because the pre-pressing bending device adopts the deformation strips which are arranged at intervals, the pre-pressing bending device can be well adapted to the shape of the first curved surface in the process, but the risk of the wavy texture of the wafer exists, so that after the operation, the die is replaced by the final-pressing bending device, and the pre-pressing is carried out on the whole surface of the wafer again until the wafer is shaped to form the final target curved-surface curved crystal.

The foregoing is considered as illustrative only of the preferred embodiments of the invention, and is presented merely for purposes of illustration and description of the principles of the invention and is not intended to limit the scope of the invention in any way. Any modifications, equivalents and improvements made within the spirit and principles of the invention and other embodiments of the invention without the creative effort of those skilled in the art are included in the protection scope of the invention based on the explanation here.

Claims

1. The preparation method of the curved surface curved crystal is characterized by comprising the following steps:

acquiring surface parameters of the curved crystal of the target curved surface, wherein the surface parameters comprise a surface radius and a surface radian;

applying first pressure to two first edges extending along a first direction of the wafer to enable the first edges to be attached to the first curved surface until the first edges form a curved surface structure matched with the shape of corresponding areas in the first curved surface; a plurality of contact points distributed along a meridional direction are arranged between the first pressure and the wafer, and the first direction is a direction corresponding to the meridional direction of the curved crystal of the target curved surface;

2. The curved crystal preparation method according to claim 1, wherein said applying a second pressure to the entirety of the wafer comprises the steps of:

applying third pressure distributed at intervals to the whole stress surface of the wafer until the stress area of the wafer forms a curved surface structure matched with the shape of the corresponding area of the first curved surface;

applying fourth pressure to the whole stress surface of the wafer until the whole stress surface of the wafer is attached to the first curved surface to form the target curved surface structure; the contact area of the fourth pressure and the wafer is larger than or equal to the area of the stress surface of the wafer.

3. The curved crystal preparation method according to claim 2, wherein the applying of the first pressure to the two first edges extending in the first direction of the wafer and the applying of the third pressures distributed at intervals to the entire force-bearing surface of the wafer are performed by a pre-press bending device;

the pre-pressing bending device comprises a female die and a male die, the male die is provided with a plurality of deformation strips distributed at intervals along the first direction, the deformation strips are positioned on one side, away from the female die, of the wafer and can deform under the action of the first pressure and the third pressure so as to be changed from a first state matched with the initial shape of the wafer into a second state matched with the shape of the corresponding area of the first curved surface.

4. The curved crystal preparation method according to claim 3, wherein the male die comprises a support, the deformation strips and force application modules in one-to-one correspondence with the deformation strips; the force application module is arranged on the bracket, is positioned on one side of the deformation strip away from the female die and is used for applying reciprocating pressure to the corresponding deformation strip; each force application module comprises a plurality of force application single bodies which are arranged at intervals along the second direction; and two ends of the deformation strip in the second direction are respectively in sliding connection with the female die or the bracket along the second direction, and the second direction is a direction corresponding to the sagittal direction of the curved crystal of the target curved surface.

5. The curved crystal preparation method of claim 4, wherein the force application unit comprises a screw member in threaded connection with the support;

6. The curved crystal preparation method according to claim 2, wherein the fourth pressure is applied to the entire force-bearing surface of the wafer by a final-pressure bending device;

the final-pressure bending device comprises a female die, a pressing component, a second explosion-proof membrane and a protective membrane, wherein the pressing component is provided with a pressing part, the pressing part is positioned on one side, deviating from the first curved surface, of the wafer, the pressing part is used for applying pressure towards the first curved surface to the wafer so that the surface, close to the first curved surface, of the wafer is tightly attached to the first curved surface, the second explosion-proof membrane is used for being attached to the back surface of the wafer, and the protective membrane is used for being attached to the reflecting surface of the wafer.

7. The curved crystal preparation method according to claim 6, wherein the pressing part comprises a pressing plate and a flexible member, the flexible member being mounted on a surface of the pressing plate opposite to the first curved surface for contacting the wafer;

8. The curved crystal production method according to any one of claims 1 to 7, wherein the target curved crystal is a curved crystal, and the curved crystal production method further comprises the following steps between the application of the first pressure to the two first edges of the wafer extending in the first direction and the application of the second pressure to the wafer:

9. The curved crystal production method according to any one of claims 1 to 7, wherein the providing of the die and the wafer to be processed comprises the steps of:

providing a concave die and a wafer to be cut;

obtaining processing parameters of the flat planar wafer after flattening treatment according to the arc length and the central line length of each side of the target curved surface curved crystal, wherein the processing parameters comprise the arc length and the central line length of each side of the planar wafer;

10. The curved crystal preparation method according to any one of claims 1 to 7, further comprising the steps of:

providing a substrate;