Disclosure of Invention
The embodiment of the invention provides a preparation method of a chip, which can effectively reduce the manufacturing cost of the chip.
In order to solve the technical problems, the invention is realized as follows:
In a first aspect, an embodiment of the present invention provides a method for manufacturing a chip, including the following steps:
S1, cutting a silicon carbide rod into a plurality of silicon carbide substrate slices, wherein the thickness of each silicon carbide substrate slice is smaller than a first set value;
s2, arranging an auxiliary layer on at least one side of the silicon carbide substrate sheet to obtain a composite sheet, wherein the total thickness of the composite sheet is larger than a second set value, and the second set value is larger than the first set value;
s3, processing the composite sheet to obtain a chip;
S4, removing the auxiliary layer on the chip.
Further, the first set value is less than 200 μm.
Further, the second set value is 200 μm to 350 μm.
Further, step S2 includes:
s21, bonding the auxiliary layer on one side of the silicon carbide substrate sheet to obtain the composite sheet;
s22, grinding the composite sheet to adjust the thickness, flatness and roughness of the composite sheet.
Further, the auxiliary layer is a polycrystalline silicon carbide layer or an aluminum oxide layer.
Further, step S2 includes:
s21', mixing auxiliary materials, and carrying out tape casting molding on the carbon surface of the silicon carbide substrate slice;
S22', sintering the silicon carbide substrate slice, and forming the auxiliary layer on the carbon surface of the silicon carbide substrate slice to obtain the composite slice;
And S23', grinding the composite sheet to adjust the thickness, flatness and roughness of the composite sheet.
Further, the auxiliary material is a mixture obtained by mixing silicon carbide powder or aluminum oxide powder serving as aggregate, clay and polyvinyl alcohol.
Further, step S2 includes:
S21', setting an adhesive on the carbon surface of the silicon carbide substrate sheet;
S22', bonding the auxiliary layer on the carbon surface of the silicon carbide substrate sheet;
S23', sintering the silicon carbide substrate sheet to obtain the composite sheet;
and S24', grinding the composite sheet to adjust the thickness, the flatness and the roughness of the composite sheet.
Further, the adhesive is a mixture obtained by mixing clay and polyvinyl alcohol with silicon carbide powder or aluminum oxide powder serving as aggregate, and the auxiliary layer is a polycrystalline silicon carbide layer or an aluminum oxide layer.
In a second aspect, embodiments of the present invention provide a chip prepared by the preparation method described in the above embodiments.
In the embodiment of the invention, the silicon carbide crystal ingot is cut into a plurality of thin-substrate slices, and the auxiliary layer is arranged on each thin-substrate slice to obtain the composite slice, so that the thin-substrate slices are prevented from being broken in the processing process, and finally, after the composite slice is processed to obtain the silicon carbide chip, the auxiliary layer is removed to obtain the silicon carbide chip with thinner thickness, thereby effectively reducing the manufacturing cost of the chip.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The method for manufacturing a chip according to an embodiment of the present invention is described below with reference to the drawings in combination with specific embodiments.
The preparation method of the chip provided by the embodiment of the invention comprises the following steps:
s1, cutting a silicon carbide rod into a plurality of silicon carbide substrate slices, wherein the thickness of each silicon carbide substrate slice is smaller than a first set value;
S2, arranging an auxiliary layer on at least one side of the silicon carbide substrate sheet to obtain a composite sheet, wherein the total thickness of the composite sheet is larger than a second set value, and the second set value is larger than the first set value;
s3, processing the composite sheet to obtain a chip;
s4, removing the auxiliary layer on the chip.
In particular, referring to fig. 2 and 3, in the method of manufacturing a chip according to an embodiment of the present invention, first, a silicon carbide rod 10 may be cut into a plurality of silicon carbide substrate pieces 20, the silicon carbide rod 10 being a silicon carbide (SiC) ingot, and the silicon carbide ingot being single-crystal silicon carbide. The thickness of each silicon carbide substrate sheet 20 may be less than the first set point so that the same silicon carbide rod 10 may cut as thin as possible and as many substrate sheets as possible. Because the SiC ingot grows at a slow rate, approximately 5cm per week, the thinner the thickness of each piece cut, the lower the cost of the SiC chip 40 produced.
Then, an auxiliary layer 30 is disposed on at least one side of the silicon carbide substrate sheet 20, one side of the silicon carbide substrate sheet 20 may be used as an epitaxial wafer (EPI), the auxiliary layer 30 may be combined with the thin silicon carbide substrate sheet 20 to obtain a composite sheet, the total thickness of the composite sheet is greater than a second set value, and the second set value is greater than the first set value. That is, the thickness of the silicon carbide substrate sheet 20 after the lamination is increased, and the thin silicon carbide substrate sheet 20 after the dicing can be effectively prevented from being directly processed to be broken during the processing.
The composite sheet may then be subjected to a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) process to obtain a chip 40. Finally, the auxiliary layer 30 on the chip 40 can be removed, and the obtained chip 40 has a thinner thickness and a complete integral structure and is not damaged. By utilizing the preparation method provided by the invention, more thinner silicon carbide substrate sheets 20 can be cut out on the same silicon carbide rod 10, so that more thinner chips 40 can be prepared, and the preparation cost of the chips 40 is effectively reduced.
It should be noted that, in the present application, the silicon carbide rod 10 may have a rod-like structure, or may have other silicon carbide ingots from which the silicon carbide substrate sheet 20 may be cut, the structure and working principle of cutting the silicon carbide rod 10 into the silicon carbide substrate sheet 20, and the method of controlling the cutting thickness of the silicon carbide substrate sheet 20, which will be understood and easily implemented by those skilled in the art, and will not be described in detail.
Therefore, in the embodiment of the present invention, by cutting the silicon carbide rod 10 into a plurality of thin silicon carbide substrate slices 20, so that the same silicon carbide rod 10 can cut more and thinner silicon carbide substrate slices 20, and then arranging the auxiliary layer 30 on each thin silicon carbide substrate slice 20 to obtain a composite slice, increasing the thickness of the silicon carbide substrate slices 20, preventing the thin silicon carbide substrate slices 20 from being broken in the processing process, and finally processing the composite slice to obtain the silicon carbide chip 40, removing the auxiliary layer 30 to obtain the silicon carbide chip 40 with thinner thickness.
According to one embodiment of the invention, the first set point is smaller than 200 μm. The second set value is 200 μm to 350 μm.
That is, as shown in fig. 2, the thickness of the silicon carbide substrate sheet 20 cut from the single crystal silicon carbide rod 10 may be less than 200 μm, and preferably the thickness of the silicon carbide substrate sheet 20 is 100 μm or less, ensuring that as many silicon carbide substrate sheets 20 as possible can be cut from the silicon carbide rod 10, so that more chips 40 can be manufactured from the same silicon carbide rod 10, and the manufacturing cost of the chips 40 can be reduced. The cut silicon carbide substrate sheet 20 may be composited with the auxiliary layer 30, and the total thickness of the silicon carbide substrate sheet 20 and the auxiliary layer 30 may be 200 μm to 350 μm.
It should be noted that, on the premise that the flatness TTV (total thickness variation) and roughness are equal to each other so as to meet the manufacturing requirement of the chip 40, the standard thickness of the silicon carbide substrate 20 after standard grinding is 350 μm, and if the thickness of the silicon carbide substrate is less than 350 μm, the silicon carbide substrate is easy to be damaged in the subsequent manufacturing process.
According to the application, the thickening treatment is carried out on the cut thinner silicon carbide substrate, so that the total thickness of the silicon carbide substrate slice 20 and the auxiliary layer 30 can meet the requirement of the subsequent chip 40 manufacturing process, and finally, the auxiliary layer 30 is removed on the prepared chip 40 by etching and other methods, so that the thickness of the prepared chip 40 is thinner, and more chips 40 can be prepared by one silicon carbide ingot, thereby effectively reducing the manufacturing cost of the chip 40.
A method of providing the auxiliary layer 30 on the silicon carbide substrate sheet 20 will be described in detail.
In some embodiments of the invention, step S2 comprises:
S21, bonding an auxiliary layer 30 on one side of the silicon carbide substrate sheet 20 to obtain a composite sheet;
s22, grinding the composite sheet to adjust the thickness, flatness and roughness of the composite sheet.
That is, in the manufacturing method of the chip of the present invention, the auxiliary layer 30 may be bonded on the silicon carbide substrate sheet 20 to obtain a composite sheet, and then the composite sheet (the total thickness of the silicon carbide substrate sheet 20 and the auxiliary layer 30 is 350 μm) is ensured by grinding the composite sheet to adjust the thickness, flatness and roughness thereof.
Alternatively, in the present application, the auxiliary layer 30 may employ a polycrystalline silicon carbide layer or an aluminum oxide layer. The single crystal SiC increases the number of silicon carbide substrate pieces 20 cut by the silicon carbide rod 10 by Bonding. By using a standard Bonding mode, a high-temperature-resistant material is bonded on monocrystalline SiC, and then standard grinding is performed, the thickness (350 um, the standard thickness of the existing SiC substrate sheet) of the composite sheet is adjusted, the flatness TTV (total thickness variation) and the roughness are equivalent, so that the manufacturing requirement of the chip 40 can be met, and the silicon carbide substrate sheet 20 is prevented from being damaged in the manufacturing process.
Meanwhile, the auxiliary layer 30 bonded on the silicon carbide substrate sheet 20 may be the same or different materials, such as high temperature resistant materials including polycrystalline silicon carbide, aluminum oxide, etc., to ensure that the composite material (composite sheet) can withstand the semiconductor process at a temperature higher than 1800 ℃. By adopting the preparation method provided by the application, more thinner silicon carbide substrate sheets 20 can be cut out on the same silicon carbide rod 10, so that more thinner chips 40 can be prepared, and the preparation cost of the chips 40 is effectively reduced. Of course, the Bonding process is understood and can be implemented by those skilled in the art, and will not be described in detail in the present application.
In other embodiments of the present invention, step S2 includes:
S21', mixing auxiliary materials, and carrying out tape casting on the carbon surface of the silicon carbide substrate sheet 20;
S22', sintering the silicon carbide substrate sheet 20, and forming an auxiliary layer 30 on the carbon surface of the silicon carbide substrate sheet 20 to obtain a composite sheet;
S23', the composite sheet is ground to adjust its thickness, flatness, and roughness.
That is, in the method for manufacturing a chip of the present invention, the silicon carbide substrate sheet 20 may be thickened by selecting an appropriate high temperature resistant material by casting, CVD for a plurality of times, or the like. The high temperature resistant material can be an auxiliary material obtained by mixing silicon carbide powder or aluminum oxide powder serving as aggregate, clay and polyvinyl alcohol. After the auxiliary materials are mixed, casting molding is performed on the carbon surface of the silicon carbide substrate sheet 20. And then sintering the silicon carbide substrate 20 at a high temperature, forming an auxiliary layer 30 on the carbon surface of the silicon carbide substrate 20 to obtain a composite sheet, and finally grinding the composite sheet to adjust the thickness, flatness and roughness of the composite sheet to obtain the composite sheet with 350 mu m.
Specifically, in the standard flow of the casting method, silicon carbide powder or aluminum oxide powder is used as aggregate, clay and polyvinyl alcohol (PVA) with the mass fraction of 3% -8% are added for mixing, casting molding is carried out on the carbon surface of the silicon carbide substrate, the thickness of the obtained auxiliary layer 30 is approximately 200um-600um, and then high-temperature sintering is carried out at the temperature of 800 ℃ to 1400 ℃. After sintering, a 350um composite sheet can be obtained by standard grinding. In the subsequent manufacturing process of the chip 40, the auxiliary layer 30 on the composite sheet is removed by etching or the like, so that the chip 40 with the thickness of less than 100 μm can be obtained.
By adopting the preparation method provided by the application, more thinner silicon carbide substrate sheets 20 can be cut out on the same silicon carbide rod 10, so that more thinner chips 40 can be prepared, and the preparation cost of the chips 40 is effectively reduced. Of course, the process principle of the casting method is understood and can be implemented by those skilled in the art, and will not be described in detail in the present application.
In some embodiments of the invention, step S2 comprises:
s21', setting an adhesive on the carbon surface of the silicon carbide substrate sheet 20;
s22', bonding the auxiliary layer 30 on the carbon surface of the silicon carbide substrate sheet 20;
s23', sintering the silicon carbide substrate sheet 20 to obtain a composite sheet;
s24", grinding the composite sheet to adjust the thickness, flatness and roughness thereof.
In other words, in the method of manufacturing a chip of the present invention, the auxiliary layer 30 may also be compounded on the silicon carbide substrate by an adhesive.
Specifically, first, an adhesive may be coated on the carbon surface of the silicon carbide substrate sheet 20, then the auxiliary layer 30 is bonded on the carbon surface of the silicon carbide substrate sheet 20, and the silicon carbide substrate sheet 20 is sintered to obtain a composite sheet. Finally, the thickness, flatness and roughness of the composite sheet are adjusted by grinding the composite sheet, so that the composite sheet with 350 mu m can be obtained.
The adhesive can be a mixture obtained by mixing silicon carbide powder or aluminum oxide powder serving as aggregate, clay and polyvinyl alcohol, and the auxiliary layer 30 can be prepared from a material with a high temperature resistant temperature of more than 2000 ℃ such as a polycrystalline silicon carbide layer or an aluminum oxide layer. By using silicon carbide powder or aluminum oxide powder as aggregate, adding clay and polyvinyl alcohol (PVA) with the mass fraction of 3% -8% as a binder, binding materials such as polycrystalline silicon carbide and aluminum oxide on the carbon surface of the silicon carbide substrate sheet 20, sintering at high temperature, wherein the sintering temperature can reach above 1700 ℃, carrying out standard grinding after sintering, and adjusting the thickness, flatness and roughness of the composite sheet to obtain the composite sheet with 350 mu m.
In the subsequent manufacturing process of the chip 40, the auxiliary layer 30 on the composite sheet is removed by etching or the like, so that the chip 40 with the thickness of less than 100 μm can be obtained. By adopting the preparation method provided by the application, more thinner silicon carbide substrate sheets 20 can be cut out on the same silicon carbide rod 10, so that more thinner chips 40 can be prepared, and the preparation cost of the chips 40 is effectively reduced.
In summary, in the embodiment of the present invention, the silicon carbide ingot is cut into a plurality of slip-sheet substrate pieces, and the auxiliary layer 30 is disposed on each of the slip-sheet substrate pieces, so as to obtain a composite sheet, prevent the slip-sheet substrate pieces from being broken during the processing process, and finally, after the composite sheet is processed to obtain the silicon carbide chip 40, the auxiliary layer 30 is removed, so that the silicon carbide chip 40 with a thinner thickness is obtained, thereby effectively reducing the manufacturing cost of the chip 40.
The present invention also provides a chip 40, and the chip 40 is prepared by the preparation method in the above embodiment (see fig. 2 and 3). Since the method for manufacturing a chip according to the embodiment of the present invention has the above technical effects, the chip 40 manufactured according to the method for manufacturing a chip of the present invention is thinner and lower in cost.
Of course, the specific preparation process of the chip 40 is understood and can be implemented by those skilled in the art, and will not be described in detail in the present application.
The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present invention and the scope of the claims, which are to be protected by the present invention.