Manufacturing method of sapphire substrate and wax dropping equipment
阅读说明：本技术 一种蓝宝石衬底的制造方法和滴蜡设备 (Manufacturing method of sapphire substrate and wax dropping equipment ) 是由 徐良 朱志平 蓝文安 支俊华 占俊杰 阳明益 刘建哲 余雅俊 于 2019-08-27 设计创作，主要内容包括：本发明涉及一种蓝宝石衬底的制造方法和滴蜡设备,该制造方法在晶片退火之后直接进行甩蜡烘烤、滴蜡测量和滴蜡抛光步骤。滴蜡抛光步骤包括：在烘烤后的蜡膜的表面晶片的正中心一次性滴下预先测定的蜡料；将滴蜡后的晶片的蜡膜面与带有热度的陶瓷盘平面相贴,使蜡滴被挤压形成圆形蜡饼,并相应地在晶片的与蜡膜面相对的背面顶起一与蜡饼形状一致的圆台；对产生圆台的晶片的背面进行抛光,使晶片的背面中间凹陷且圆台的外缘与晶背面的其余部分平滑过渡,并成为中间凹陷底部的圆面。滴蜡设备包括吸盘、点胶阀、储蜡桶、导蜡管和数显调压阀。本发明的蓝宝石衬底的制造方法和滴蜡设备,省去了晶片弯曲度分选工作,并能大幅提升衬底的产品合格率。(The invention relates to a manufacturing method of a sapphire substrate and a wax dropping device. The wax dropping polishing step comprises the following steps: dripping wax material measured in advance at one time on the right center of the surface wafer of the baked wax film; attaching the wax film surface of the wafer on which the wax is dropped to the plane of the ceramic disc with heat, so that the wax drops are extruded to form a circular wax cake, and correspondingly jacking a circular table with the shape consistent with that of the wax cake on the back surface of the wafer opposite to the wax film surface; and polishing the back surface of the wafer with the circular truncated cone, so that the middle of the back surface of the wafer is sunken, and the outer edge of the circular truncated cone is smoothly transited with the rest part of the back surface of the wafer and becomes a circular surface at the bottom of the middle sunken part. The wax dropping device comprises a sucker, a dispensing valve, a wax storage barrel, a wax guide pipe and a digital display pressure regulating valve. The manufacturing method of the sapphire substrate and the wax dropping equipment of the invention save the work of sorting the wafer curvature and greatly improve the product percent of pass of the substrate.)
1. A method for measuring and calculating the amount of wax required to be dropped in the manufacturing process of a sapphire substrate is characterized by comprising the following steps:
a. selecting a sapphire wafer after wax throwing as a wafer sample wafer;
b. baking the selected sapphire wafer sample to soften and make the wax film on the surface of the wafer sample soft and sticky;
c. dripping a trace amount of wax material on the exact center of the wafer sample sheet on the surface of the softened wax film;
d. attaching the wax film surface of the wafer sample wafer on which the wax is completely dropped to the plane of the ceramic disc with heat, so that the wax drops are extruded to form a circular wax cake, and correspondingly jacking a circular table with the shape consistent with that of the wax cake on the back surface of the wafer sample wafer opposite to the wax film surface;
e. comparing the formed circular truncated cone with a preset size requirement;
f. repeating the steps c-e until the formed round platform meets the preset size requirement;
g. the total amount of wax dropped is recorded and is the desired amount of wax dropped.
2. A manufacturing method of a sapphire substrate, characterized in that the manufacturing method directly performs a wax throwing baking step and a wax dropping measuring step and a wax dropping polishing step after a wafer annealing step, wherein the wax dropping polishing step comprises:
dropping a wax material determined by the measurement method according to claim 1 at one time from the very center of the wafer on the surface of the wax film after baking;
b', attaching the wax film surface of the wafer on which the wax is dropped to the plane of the ceramic disc with heat, so that the wax drops are extruded to form a circular wax cake, and correspondingly jacking a circular table with the shape consistent with that of the wax cake on the back surface of the wafer opposite to the wax film surface;
and c', polishing the back surface of the wafer for generating the circular platform, so that the middle of the back surface of the wafer is sunken, the outer edge of the circular platform is smoothly transited with the rest part of the back surface of the wafer, and finally the circular surface at the bottom of the middle sunken part is formed, thus forming the sapphire substrate.
3. The method of manufacture of claim 2, wherein the wax throwing baking step comprises:
rotating the annealed wafer and throwing wax onto one surface of the rotated wafer to form a wax film covering the surface; the wafer is stopped from rotating, and the wafer is baked so that the wax film is softened and has viscosity.
4. The manufacturing method according to claim 2,
the wax material of the dripping wax is new liquid wax, solid wax is melted by heating or liquid wax is recovered.
5. The wax dropping device used in the manufacturing method according to any one of claims 1 to 4, comprising a suction cup (1) for fixing a wafer, a dispensing valve (2), a wax storage barrel (3), a wax guiding tube (4) and a digital pressure regulating valve, wherein the dispensing valve (2) is arranged above the suction cup (1) in a spinning manner and can freely move in the vertical direction and the horizontal direction, the dispensing valve (2) is connected with the wax storage barrel (3) through the wax guiding tube (4), and the digital pressure regulating valve is arranged in the wax guiding tube (4).
6. The wax dispensing apparatus of claim 5,
the dispensing valve (2) is movably arranged above the sucker (1) through a movable sliding rail and a supporting frame.
Technical Field
The invention relates to the technical field of semiconductor manufacturing, in particular to a manufacturing method of a sapphire substrate and wax dropping equipment.
Background
Sapphire has a series of advantages of high acoustic velocity, high temperature resistance, corrosion resistance, high hardness, high light transmittance, high melting point and the like, and is widely applied as an LED substrate.
In the manufacturing process of the sapphire substrate, slicing, double-side grinding, copper polishing and CMP polishing are mainly performed. The sapphire substrate is a high-temperature grown single crystal, the hardness of which is second only to that of diamond, and the melting point of which is 2250 ℃. Difficult growth conditions result in expensive sapphire crystal costs. The in-sheet thickness values of the cut sapphire wafer are 780-800 micrometers (the in-sheet thickness difference is less than 30 micrometers), the sapphire substrate is subjected to a double-side grinding process on the basis of the cut sapphire wafer, the in-sheet thickness values of the ground sapphire substrate are 690-710 micrometers (the in-sheet thickness difference is less than 10 micrometers), and then the subsequent processes of chamfering, annealing, wax pasting, copper polishing, chemical mechanical polishing and the like are carried out, so that the processing of the sapphire substrate is completed.
Because the relation of sapphire high hardness, the cutting grinding operation in-process wafer can produce stress, and these stress release after the annealing make the wafer take place to deform, need carry out deformation with the wafer when the wax is pasted and select separately, drip wax at the convex surface and form the wax membrane, carry out the polishing operation with the concave surface, then because deformation is difficult to control, need complicated BOW to select separately the step to because finished product face type is inconsistent, be difficult to reach epitaxial producer's demand.
Disclosure of Invention
An object of the present invention is to solve the above problems, and the present invention provides a method of manufacturing a batch of sapphire substrates having a surface shape that tends to be uniform, and a wax dropping apparatus.
According to one aspect of the invention, a method for measuring and calculating the amount of wax dropping required in the manufacturing process of a sapphire substrate is provided, and the method comprises the following steps: a. selecting a sapphire wafer after wax throwing as a wafer sample wafer; b. baking the selected sapphire wafer sample to soften and make the wax film on the surface of the wafer sample soft and sticky; c. dripping a trace amount of wax material on the exact center of the wafer sample sheet on the surface of the softened wax film; d. attaching the wax film surface of the wafer sample wafer on which the wax is completely dropped to the plane of the ceramic disc with heat, so that the wax drops are extruded to form a circular wax cake, and correspondingly jacking a circular table with the shape consistent with that of the wax cake on the back surface of the wafer sample wafer opposite to the wax film surface; e. comparing the formed circular truncated cone with a preset size requirement; f. repeating the steps c-e until the formed round platform meets the preset size requirement; g. the total amount of wax dropped is recorded and is the desired amount of wax dropped.
According to a second aspect of the present invention, there is provided a method of manufacturing a sapphire substrate, which directly performs a wax throwing baking step, a wax dropping measuring step, and a wax dropping polishing step after a wafer annealing step.
Wherein, the wax dropping polishing step comprises: dropping a wax material determined by the measurement method according to
Wherein, should get rid of the wax and toast the step and include: rotating the annealed wafer and throwing wax onto one surface of the rotated wafer to form a wax film covering the surface; the wafer is stopped from rotating, and the wafer is baked so that the wax film is softened and has viscosity.
Wherein the wax material of the dripping wax is new liquid wax, solid wax melted by heating or liquid wax recovered.
According to a third aspect of the present invention, there is provided a wax dropping apparatus used in the manufacturing method, comprising a suction cup for fixing a wafer, a dispensing valve, a wax storage barrel, a wax guide pipe and a digital pressure regulating valve, wherein the dispensing valve is arranged above the suction cup in a spinning manner and freely movable in vertical and horizontal directions, the dispensing valve is connected with the wax storage barrel through the wax guide pipe, and the digital pressure regulating valve is located in the wax guide pipe.
Wherein, the dispensing valve is movably arranged above the sucker through a movable sliding rail and a supporting frame.
According to the manufacturing method of the sapphire substrate and the wax dropping device, the complex wafer curvature sorting work is omitted, the problems that the surface type of the finished product substrate is poor and deformation intervals are dispersed due to abnormal shape after wafer annealing are solved, and the product percent of pass is greatly improved.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
fig. 1 shows a schematic view of a wax dropping apparatus for a sapphire substrate according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below according to examples. While exemplary embodiments of the present disclosure have been shown in the specification, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
In the conventional method for manufacturing the sapphire substrate, after cutting, chamfering, wax throwing, baking and annealing, a curvature sorting procedure is required, the concave surface and the convex surface of a wafer are determined, the concave surface is used as the front surface polishing operation, and the stress release after annealing is difficult to control, so that the sorting work difficulty is increased, and the polished surface is difficult to confirm. The basic idea of the invention is that the operation of dropping wax and pasting is added after the wax is thrown and baked, the surface shape of the wafer is trimmed, the trimmed wafer front is directly polished without sorting, the process is simplified, and the product yield is improved.
A manufacturing method of a sapphire substrate directly performs a wax throwing baking step, a wax dropping amount measuring and calculating step and a wax dropping patch polishing step after a wafer annealing step, wherein the wax dropping amount measuring and calculating step comprises the following steps: selecting a sapphire wafer after wax throwing as a wafer sample wafer; baking the selected sapphire wafer sample to soften and make the wax film on the surface of the wafer sample soft and sticky; dripping a trace amount of wax material on the exact center of the wafer sample sheet on the surface of the softened wax film; attaching the wax film surface of the wafer sample wafer on which the wax is completely dropped to the plane of the ceramic disc with heat, so that the wax drops are extruded to form a circular wax cake, and correspondingly jacking a circular table with the shape consistent with that of the wax cake on the back surface of the wafer sample wafer opposite to the wax film surface; comparing the formed circular truncated cone with a preset size requirement; repeating the steps of dripping wax, pasting and extruding wax until the formed round table meets the preset size requirement; the total amount of wax dropped is recorded and is the desired amount of wax dropped.
The wax dropping and pasting step comprises the following steps: dripping the measured wax material at one time on the right center of the surface wafer of the baked wax film; attaching the wax film surface of the wafer on which the wax is dropped to the plane of the ceramic disc with heat, so that the wax drops are extruded to form a circular wax cake, and correspondingly jacking a circular table with the shape consistent with that of the wax cake on the back surface of the wafer opposite to the wax film surface; and polishing the back surface of the wafer with the circular truncated cone, so that the back surface of the wafer is slightly concave, the outer edge of the circular truncated cone is in smooth transition with the rest part of the back surface of the wafer, and finally the wafer becomes a circular surface with a slightly concave bottom, and the sapphire substrate is formed.
The wax material of the dripping wax can be new liquid wax, solid wax melted by heating and liquid wax recovered, and the wax material is required to be consistent with the wax material of the throwing wax. The wafer may be round or square, with dimensions including but not limited to 2-12 inches.
The wax throwing and baking step comprises: rotating the annealed wafer and throwing wax onto one surface of the rotated wafer to form a wax film covering the surface; the wafer is stopped from rotating, and the wafer is baked so that the wax film is softened and has viscosity.
As shown in figure 1, the invention also relates to wax dropping equipment used in the preparation method, which comprises a
In a specific embodiment, the dispensing
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
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