TW442869B - Method for avoiding poor photoresist spreading caused by ion implantation - Google Patents

Abstract

The present invention include a step of performing a pre-treatment, after ion implantation, for improving the surface characteristic of the oxide. The pre-treatment includes using a solution composed of ammonia and hydrogen peroxide. The pre-treatment is executed at a temperature of about 40-50 DEG C, preferably 45 DEG C. The ammonia, hydrogen peroxide and water of the solution are at a ratio of about 1:2-6:15-25, preferably 1:4:20. The use of the pre-treatment can improve the surface roughness of the silicon dioxide, thereby eliminating the poor photoresist spreading problem, particularly the photoresist spreading at the edge of the wafer.

Description

442869 V. Description of the invention (l) --- Field of the invention: The present invention relates to a semiconductor process, in particular a new method for improving poor photoresist coating caused by ion implantation. Background of the Invention: Integrated circuit (IC) technology has already made the density of components into a single size, which can increase the size of semiconductor integrated components. After reducing the size of integrated components, integrated circuits have new challenges. For example, the dynamic randomness caused a reduction in storage capacity. The role played by the density of wafers on semiconductor wafers is also important. An important process in building a multi-layer structure, the same alignment. Lithography and etching include the formation of lithographic processes with very fine patterned semi-micron resolution capabilities that affect the results of the process. There is a significant improvement 'and an increase in electronic species. By reducing the integration density of electronic circuits. As electronic circuits continue to shrink in size during the manufacturing process, there is a lack of reliability. Continuous improvement, so in the lithography process, the lithography and etching also provide multiple layers of accurate photoresist patterns as a mask during the manufacturing process. For the body element, it needs a kind of equipment, so the photoresist coating is also required. It will be greatly suspended, and Yuan's court said that Du Yi rolled the fossil and built the office again. ^ ^ Publication 7 The gate is located between the drain and source of the semiconductor. Adding an appropriate voltage between φ BI. _ „Between the gate and the semiconductor can control the channel current between the source and the drain. 0 ^ 升 联 作; I3) A threshold voltage is involved in the port Ionic cloth ° 枉 步骤 β Generally speaking, the use of a comprehensive ion implantation

44286 9 V. Description of the invention (2) Ion doping is used to adjust the ion concentration of p-well and N-well 'and then adjust the starting voltage. It is typical to use the collar to adjust the starting voltage. The planting energy is between 2 5-40 K e V, and the dosage is about half a million. „W tablet mother 100,000 cm 1 Ε 1 1-1 Ε 1 2 ions. For CMOS, the sincerity of the priests and the respect of the beginning of the voltage and the voltage ion implantation caused the poor photoresistance coating on the edge of the wafer. Chuan Xiong showed + +, β The first method to find the existing Hanshan is to increase the amount of coated photoresist. This method will convert the cost of the Muga system to the priests and shishigan scalpel table posts and cause a lot of industrial waste.疋 After the growth of the Yuancheng oxide layer, comprehensive ion doping was performed, and then photoresist was applied to facilitate the patterning of subsequent uses. Atomic force microscope was used to observe Chengxian sowing ^ [/ 卜 S Master JC: Later oxide layer ", And the ion implantation is 6.m angstrom and 14", it can be seen that the surface of the rough seam differentiation layer on both surfaces becomes more ΓΓ, and the two-child decoration will lead to the adverse effect of the oxygen term: ⑴ Zaiguang 、 The surface of Han Yu's photoresist coating has two frictional forces. During this rough coating process, there will be greater Area, so if you want to reach ^ the surface will be larger than the smooth surface. These two disadvantages: soil: the amount of photoresistance required to block the coating will become a problem. Defective ° In order to solve the above-mentioned table for processing the gate oxide layer < perform a pre-treatment, use the characteristics of organic solvents to make its surface characteristics: Second, the above-mentioned pre-treatment can change the water surface of the wafer (hydrophilic). The water-based (hydrophobic) is transformed into the organic solvent used to describe the adhesion of the photoresist on the wafer, but the industrial pollution.-Yes, and it is harmful to the human body, and will increase

44286 9 V. Description of the invention (3) Therefore, the present invention proposes a new concept to solve the problem of poor photoresist coating and avoid the generation of toxic substances. OBJECTS AND SUMMARY OF THE INVENTION The object of the present invention is to provide a method for improving the phenomenon of poor photoresist coating caused by ion implantation. Another object of the present invention is a method for improving the rough surface of an oxide. Another object of the present invention is to treat the surface of the oxide after ion implantation with a specific solution to improve its surface characteristics. The ion implantation step will cause the surface of the silicon dioxide to be roughened. Therefore, the present invention discloses a method for improving the poor coating of the photoresist on the wafer. The steps of the present invention include performing a pre-treatment after ion implantation to improve the surface characteristics of the photoresist to be coated. The solution used in the pretreatment process of the present invention is an aqueous solution composed of aqueous ammonia (40%) and hydrogen peroxide (H 20 2). Using this treatment can improve the surface roughness of silicon dioxide and solve the problem of poor photoresist coating, especially at the edge of the wafer. The mechanism of its chemical reaction is to achieve a dynamic equilibrium state of reversible reaction between oxide dissolution and oxide deposition, that is, a reversible chemical reaction equilibrium including oxide (ammonia), ammonia (NΗ4〇Η), and hydrogen peroxide (Η202). , Changing the arrangement of the atomic lattice on the surface of silicon dioxide and

d42869 V. Description of the invention (4) --- It can improve the surface roughness caused by the ion implantation process of adjusting the starting voltage. In addition, this step can remove by-products or particles produced by ion implantation at the same time. The temperature range of the processing step is about 40-50 degrees Celsius, preferably 45 degrees Celsius. The solution The composition of ammonia water (NΗ40Η): hydrogen peroxide (H2O2): water (h2〇) is about J. 2_6 15-25, preferably 1: 4: 20 *. * Detailed description of the invention: The present invention What is to be disclosed is a method for reducing the surface roughness of oxides. In the present invention, the methods disclosed include, but are not limited to, treating the surface of an oxide layer through ion implantation to improve the effect of photoresist coating. ί Hair: a solution used to treat ion implantation: tritium I :, surface to improve its surface characteristics β, its detailed description will be described below. Refer to Figure-this is a flowchart example of the method steps. In this step, you can first prepare or provide a semiconductor material as a substrate or wafer. You can use ^ to limit the single crystal hair with the crystal orientation of <1GG> as the hair! If the embodiment = round, then 'some already Known processes such as the production of well-type "heterogeneous and isolated regions" are made in wafers using known edge region technology.… Or field oxidation is followed by a step of forming oxide layers on the wafer in step 110. On, like

ΕΒϋ 442869 V. Description of the invention (5) The silicon dioxide layer is used as a gate oxide layer in the process of making the transistor. This silicon dioxide layer is generally formed by a thermal oxidation method, and the process temperature is about 700 to A thickness of about 50 to 200 angstroms is formed between 110 ° C. Of course, a general technique such as chemical vapor deposition using TEOS as a reactant can also form a silicon dioxide layer. The pre-treatment 'step 120 can be performed after the ion implantation (step 115). The above-mentioned ion implantation can be an ion implantation for adjusting the start voltage or an ion implantation for other purposes. The background description shows that the ion implantation step will cause a roughening of the surface of the silicon dioxide. Therefore, the use of the pretreatment step of the present invention can improve the influence caused by the above phenomenon. In addition, the formulation of the present invention can be used to treat the surface of silicon dioxide to achieve better surface characteristics even without the steps of ion implantation. Therefore, the processing of the present invention after the ion implantation of the initial voltage adjustment is only one of the preferred application embodiments of the present invention, and is not intended to limit the scope of application of the present invention. The pretreatment step proposed in the present invention uses a solution to process the silicon dioxide layer. For a preferred embodiment, the above solution formula is APM (ammonin peroxide m] t Xture; APM), which contains ammonia (νη4οη). ), The aqueous solution β composed of hydrogen peroxide (h2o2) can be used to recover the surface of the silicon dioxide, reduce its thickness, and even be flatter than the surface without ion implantation. Similarly, the application of the invention can solve the problem of poor photoresist coating, especially at the edge of the wafer. The results of observation with an atomic force microscope are shown in the figure, and the roughness is reduced to about 2.86 angstroms, which is even less than that of

Page 8 44286 9 V. Description of the invention (6) Surface roughness 6.60 5 angs flat even after ion implantation. The mechanism of its action is to achieve the dynamic equilibrium state of the reversible reaction of oxide dissolution and oxide deposition, that is, the reversible reaction including oxide (oxi de), ammonia (MAY), and hydrogen peroxide (h2O2). Chemical reaction equilibrium. From the experimental data in Figure 2, it can be seen that the use of APM-enhanced dynamic equilibrium reaction can effectively reduce the coarse chain degree on the surface of the dioxide and further eliminate the factors of poor coating in the subsequent lithographic photoresist coating process. The above-mentioned reversible chemical reaction has the effect of "tempering" the film, which can modify the arrangement of the atomic lattice on the surface of silicon monoxide and improve the surface coarse sugar caused by the initial voltage ion implantation. In addition to ..,, + J M is used to remove by-products or particles produced by ion implantation. Λ 对 pair cup dipper When the cage is the main two l * λα This release can also reduce the photoresist spin coating

The resistance on the surface of the Tao film and the parachute umbrella R Tu You λ # π such as &amp; and reduce the use of the first resistance, in order to facilitate the photo-resistance. In the conventional example, the temperature range of 佶 4 ^ ^ ^ ^ 4 0 -5 0 ^ pi h A PM step temperature is about Fu Shi, the degree of 4 ϋ bU degree 'is better to take the ice, 1 ammonia (NH40H ): Hydrogen peroxide (fj 45 degrees. Composition of Luo solution ... 2-6: Photoresist on silicon surface ": The oxidation characteristics of the two-step treatment in AP two steps have been improved, so one is provided. The subsequent photoresist coating on the silicon oxide surface can improve the coating surface of condition a to facilitate the image. This method is different from the conventional technique; = the polarity of the current Japanese yen surface with poor cloth is used to

4428 6 9 V. Description of the invention (7) Increase the adhesion of photoresist. The present invention uses an aqueous solution of nitrogen water and hydrogen peroxide to achieve a chemical reaction equilibrium between the oxide and the solution. After the reaction, the thickness of the oxide layer will not decrease, and the net reaction of the APM pretreatment can obtain flat silicon dioxide. Surface β In addition, the amount of photoresist coating can be reduced from 3.5 cc per wafer to 2.0 c per wafer, so the present invention can also reduce the cost of the process. There will also be significant improvements in photoresist coating on wafer edges. The invention is described above with reference to the preferred embodiments. Those skilled in the art can make some modifications to the invention without departing from the spirit of the invention. The scope of patent protection should be regarded as the scope of the attached patent application and its equivalent. It depends.

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Claims (1)

442869 VI. Application Patent Scope 1. A method for improving photoresist coating on an oxide layer, the method comprising: providing a wafer having an oxide layer formed thereon; performing a processing step using an aqueous solution containing ammonia (NΗ40Η) And a mixed solution of hydrogen peroxide (H2O2) to treat the oxide layer; and coating a photoresist on the oxide layer. 2. The method for improving photoresist coating on an oxide layer according to item 1 of the patent application scope, further comprising performing an ion implantation before the processing step. 3. The method for improving photoresist coating on an oxide layer as described in item 1 of the scope of the patent application, wherein the volume percentage of the above mixed solution ammonia water: hydrogen peroxide: water is about 1: 2-6: 1 5-2 5 . 4. For the method for improving photoresist coating on an oxide layer according to item 3 of the patent application, wherein the volume percentage of the above mixed solution is about 1: 4: 20. 5. For the method for improving photoresist coating on the oxide layer according to item 1 of the patent application scope, wherein the temperature range for performing the above-mentioned processing steps is between about 40 and 50 degrees Celsius. 6. For the method for improving photoresist coating on an oxide layer according to item 5 of the patent application scope, wherein the temperature range for performing the above processing steps is about 45 degrees Celsius. Page 12 442869 6. Application Patent Range 7. A method for improving photoresist coating on an oxide layer, the method includes: providing a wafer having an oxide layer formed thereon; performing an ion adjusting the starting voltage Implanted in the wafer, the ion implantation causes the surface of the oxide layer to be roughened; performing a processing step to treat the oxide layer with a mixed solution containing ammonia and hydrogen peroxide to reduce the surface roughness of the oxide layer; And coating a photoresist on the oxide layer. 8. The method for improving photoresist coating on an oxide layer according to item 7 of the scope of patent application, wherein the volume percentage of the above mixed solution ammonia water: hydrogen peroxide: water is about 1: 2-6: 1 5-2 5 . 9. For the method for improving photoresist coating on an oxide layer according to item 8 of the patent application, wherein the volume percentage of the above mixed solution is about 1: 4: 20. 10. The method for improving photoresist coating on an oxide layer according to item 7 of the scope of patent application, wherein the temperature range for performing the above-mentioned processing steps is about 40-50 degrees Celsius. 11. The method for improving photoresist coating on an oxide layer according to item 10 of the patent application range, wherein the temperature range for performing the above-mentioned processing steps is about 45 degrees Celsius. 1 2. —A method for improving oxide roughness, characterized by Page 13 44286 9 VI. Scope of Patent Application A mixed solution of ammonia and hydrogen peroxide is used to treat the oxide to reduce the thickness of the oxide layer. 1 3. The method for improving the surface roughness of an oxide layer according to item 12 of the scope of patent application, wherein the volume percentage of the above mixed solution ammonia water: hydrogen peroxide: water is about 1: 2-6: 1 5-2 5 = 1 4. The method for improving the surface roughness of an oxide layer according to item 13 of the scope of patent application, wherein the volume percentage of the above mixed solution is about 1: 4: 20. 15. The method for improving the surface roughness of an oxide layer according to item 12 of the scope of patent application, wherein the above mixed solution is used in a temperature range of about 40 to 50 degrees Celsius. 16. The method for improving the surface roughness of an oxide layer according to item 15 of the scope of patent application, wherein the above mixed solution is used in a temperature range of about 45 degrees Celsius. 1 7. A method for improving the roughness of oxides, which is characterized by using an aqueous solution containing ammonia and hydrogen peroxide in a temperature range of about 40 to 50 degrees Celsius, preferably 45 degrees Celsius. The oxide is treated at a low temperature, and the composition of the solution is: oxygen water: hydrogen peroxide: water ratio of about 1: 2-6: 1 5-2 5, preferably 1: 4: 2 0 to improve the Roughness of oxides. Page 14