TWI768329B - Physical dry surface treatment method of semiconductor wafer and composition for surface treatment thereof - Google Patents

Abstract

The invention relates to a physical dry surface treatment method of a semiconductor wafer and a composition for surface treatment thereof. The composition for surface treatment of the present invention can be used to remove, polish or thin the surface and thickness of the semiconductor wafer. When the semiconductor wafer is regenerated or thinned, it is used for high-speed blast grinding of the surface of the semiconductor wafer, and the surface treatment composition contains a mixture of soft elastic carriers and hard particles. It has abrasive material adhering to hard particles, which is aimed at the surface to be treated of the semiconductor wafer to remove the coating or metal layer of the wafer on the surface, and can achieve the effect of polishing. Outside recycling. Compared with the conventional chemical mechanical polishing or dry and wet etching processes, this new method does not need to use liquids such as wet abrasives and chemical etching agents, abrasive slurry, and water. Not only can it save the cost of the above-mentioned abrasive slurry and the disposal of harmful substances produced by subsequent processing, but also can reduce the damage to the future environment.

Description

Physical dry surface treatment method of semiconductor wafer and composition for surface treatment thereof

The present invention belongs to a surface treatment technology of a semiconductor substrate, and specifically refers to a physical dry surface treatment method of a semiconductor wafer and a composition for surface treatment thereof, so as to improve the efficiency of removing, polishing or thinning the surface of the semiconductor substrate , not only fast and safe and not easy to be broken, but also without the use of chemical liquids or water during operation, reducing environmental damage, and improving the safety of personnel during operation.

Due to the rapid and mature development of integrated circuit technology on semiconductor devices, the semiconductor industry has become one of the booming industries. On the other hand, semiconductor wafers are produced by many steps such as film formation, exposure, etching, polishing, and cleaning of substrates such as silicon wafers. Generally, fabs need to use up to 30% or even more of the monitoring and testing wafers (Monitor Wafer, Dummy Wafer) in mass production. Test wafers. The early test wafers were discarded together with the outdated wafers after use, resulting in a lot of toxic industrial waste. Later, with the rapid development of the industry, the size of the wafer material became larger, and the cost became higher and higher, and gradually developed The Reclaimed Wafer industry is developed, which is to replace the used test wafers and eliminate the coatings (such as insulating films or metal films) on the wafers. After grinding, polishing and other procedures, the material can be continuously recycled and reused.

The existing method for regenerating semiconductor wafers mainly uses wet etching technology to remove the coating on the surface of the wafer, such as insulating coatings such as SiO2 and Si3N4, or metal coatings such as Al, Cu, and Ti. After lapping and/or grinding the surface of the semiconductor wafer, chemical mechanical polishing (Chemical Mechanical Polish, CMP), or direct chemical mechanical polishing, is pre-planarized, and finally the wafer surface is After reaching the original state, the semiconductor wafer can be reused repeatedly within a predetermined thickness.

However, according to the composition of different coatings, different corrosive liquids (such as hydrofluoric acid) must be used to etch the regenerated wafers, which increases the complexity of the etching process, and also generates toxic gases during the process, causing the process to increase. security issues. In addition, the corrosion efficiency of corrosive liquids for different coating compositions is also different, which leads to the problem of uneven surface thickness of the regenerated wafer, and the surface of the regenerated wafer after wet etching is easy to be dissolved by the corrosive liquid. Ions or impurities adhere and leave contaminants on the surface of the regenerated wafer. As a result, the remaining contaminants must be removed before subsequent processes can be performed, which is also a considerable burden on the manufacturing cost. In addition, chemical mechanical polishing will also produce waste such as waste grinding liquid and grinding sludge. These chemical wastes will harm our environment. In order to prevent the ecological environment from being damaged by toxic chemical waste liquids, etching or The chemical waste liquid produced in the chemical mechanical polishing process cannot be discharged arbitrarily, so manufacturers need to pay for the cost of chemical waste liquid recycling, equipment and labor costs.

Although some industry players have proposed the use of dry sandblasting to remove the coating on the wafer surface, such as Chinese Patent Announcements No. M320168, No. M324847 and Announcement No. 200524031, etc., to reduce the problems caused by etching or grinding to remove the coating, but As shown in the first figure, the sandblasting system uses hard materials such as natural diamonds, artificial diamonds, tungsten carbide, boron carbide, etc. as abrasive materials, and its particle size is about 1um~10um. The speed is high, and the impact on the surface (15) of the wafer (10) is a short click state, and internal stress is formed in the wafer (10), which not only damages the wafer (10), but also leads to a decrease in yield , and if the wafer (10) is thin, cracks or cracks may occur, and because it does not have a grinding effect, the surface (15) of the wafer (10) after removing the coating is relatively uneven (as in Section 1). As shown in the second picture], and there may be residual metal coating (A), so it still needs to be planarized by chemical mechanical polishing.

Furthermore, as applications such as memory and power devices move toward smaller size and higher performance, thinner wafers can bring numerous benefits, including ultra-thin packages and, consequently, smaller form factor, also includes improved electrical performance and better thermal performance. Therefore, the thinning process demand for wafer thinning is also increasing. The wafer thinning process method is similar to the aforementioned method of regenerating wafers. Most of them use chemical mechanical polishing technology for thinning, so they face the same cost and waste liquid treatment problems.

In other words, the current surface treatment of semiconductor wafers such as removal, polishing or thinning cannot fully meet the requirements. too high to And the problem of high breakage rate and low yield rate, and at the same time, it will extend the trouble of processing a large amount of waste liquid. How to solve the above problem is expected by the industry, and it is also a technical problem to be solved by the present invention.

The reason is that the inventors of the present invention have conducted in-depth discussions on the problems faced by the existing regenerated wafers, and have finally successfully developed a physical dry surface treatment of semiconductor wafers through continuous improvement and trial production based on the needs of technological development in recent years. The method and the composition for surface treatment thereof can overcome the disadvantages and inconveniences caused by the use of etching or grinding to remove the coating film and save the manufacturing process and time.

Therefore, the main purpose of the present invention is to provide a physical dry surface treatment method for semiconductor wafers, which can simplify the surface treatment process of regenerated wafers, improve surface machining accuracy, improve surface roughness, and improve surface treatment efficiency. speed.

In addition, another main purpose of the present invention is to provide a physical dry surface treatment method for semiconductor wafers, which can reduce the pollution of chemicals, not only save the procedures and equipment for waste liquid treatment, so that the regenerated wafer process can be More environmentally friendly and safe.

Furthermore, another main object of the present invention is to provide a composition for surface treatment of semiconductor wafers, which can provide a better pressure-relief effect during grinding, and can reduce the metamorphic layer when the surface of the regenerated wafer is removed, thereby Reducing wafer cracks can further improve the yield of the overall process.

Based on this, this creation is mainly through the following technical means to create The body achieves the aforementioned objects and effects: it comprises a step of spraying the surface treatment composition to remove the surface to be treated of a semiconductor wafer at a specific spray angle;

Wherein the composition for surface treatment includes a series of soft elastic carriers and a series of hard microparticles, wherein these soft elastic carriers are selected from elastic materials with stickiness, and the particle size of these soft elastic carriers is 10um~ 150um, and the particle size of these hard particles is 1500~30000 meshes in the international mesh standard [MESH];

When the composition for surface treatment is in high-speed contact with the surface to be treated of the semiconductor wafer, the soft elastic carrier will deform and form high-speed friction and sliding on the surface to be treated. The to-be-treated surface produces a grinding effect, which in turn produces the effect of removing or polishing the to-be-treated surface of the semiconductor wafer.

Thereby, through the specific realization of the above technical means, the present invention not only has a very simple and fast manufacturing process, but also can improve the processing accuracy, and at the same time, it does not need to use corrosive liquid, so as to avoid the generation of toxic gas in the process, and greatly improve the safety of the process. At the same time, there will be no waste such as waste grinding liquid and grinding sludge, which will reduce the damage to the ecological environment, thereby reducing the cost of chemical waste liquid recycling and processing and the required equipment and labor, which can greatly reduce the cost of waste. process cost to increase its added value and further improve its economic benefits.

And the present invention utilizes the following technical means to further achieve the aforementioned purposes and effects; such as:

The soft elastic carrier system is selected from plastic rubber fibers as raw materials The resulting soft elastic composite has adhesive properties.

The hard microparticles may be selected from diamonds or mixtures thereof.

The hard particles can be selected from boron nitride or mixtures thereof.

The hard microparticles can be selected from tungsten carbide or mixtures thereof.

The specific included angle is 2 degrees to 60 degrees.

The speed at which the composition for surface treatment is ejected is 50 m/s to 200 m/s.

The above-mentioned surface treatment method can be selected to carry out two or more passes, and the particle size of the hard particles of the surface treatment composition in each blasting surface treatment step is different, which is used for rough removal, fine removal and fine polishing in sequence. processing steps.

The semiconductor wafer can be a sapphire substrate, a glass substrate or a quartz substrate.

In order to enable your examiners to further understand the structure, features and other purposes of the present invention, the following are preferred embodiments of the present invention, which are described in detail in conjunction with the drawings, so that those who are familiar with the technical field can implement them in detail.

10: Wafer

15: Surface

20: Sandblasting

A: Residual metal coating

100: Semiconductor Wafers

105: Surface to be treated

500: Composition for Surface Treatment

50: Soft elastic carrier

55: Hard particles

60: debris

Figure 1: A schematic diagram of the operation of the conventional method for removing the coating on the wafer surface by sandblasting technology.

Figure 2: The enlarged schematic diagram of the wafer surface after the conventional sandblasting technique is used to remove the coating on the wafer surface, wherein (A) is a partial re-enlarged schematic diagram to illustrate its roughness.

The third figure: the composition for surface treatment of the semiconductor wafer of the present invention A schematic diagram of mixing, wherein (A) is a schematic diagram of the mixing of the surface treatment composition, and (B) is an enlarged schematic diagram of a single surface treatment composition.

Figure 4: Schematic diagram of the spray grinding structure of the physical dry surface treatment method of the semiconductor wafer of the present invention.

Figure 5: Schematic diagram of the action of spray grinding the surface treatment composition on the wafer surface in the physical dry surface treatment method of the semiconductor wafer of the present invention, wherein (A) is a single surface treatment composition and the wafer surface grinding. state.

Figure 6: A schematic diagram of the state of the composition for surface treatment of the semiconductor wafer of the present invention after the surface of the wafer is spray-polished.

The present invention relates to a physical dry surface treatment method for semiconductor wafers and a composition for surface treatment thereof. The accompanying drawings illustrate specific embodiments of the present invention and their components, all related to front and back, left and right, top and bottom, The upper and lower, and horizontal and vertical references are for convenience of description only, and do not limit the invention, nor restrict its components to any position or spatial orientation. The dimensions specified in the drawings and the description can be changed according to the design and requirements of the specific embodiment of the present invention without departing from the scope of the patent application of the present invention.

The physical dry surface treatment method of semiconductor wafer and the composition for surface treatment of the present invention are as shown in (A) and (B) of the third figure, and the composition (500) for surface treatment of semiconductor wafer is composed of a series of A soft elastic carrier (50) and a series of hard microparticles (55) are mixed, wherein the soft elastic carrier (50) is selected from soft elastic materials with stickiness, such as plastic, rubber or silicone as the base The soft elastic composite made from the raw material of the material, the particle size of the soft elastic carriers (50) is 10um~150um, and the hard particles (55) can be selected from hard materials such as diamond, boron nitride, tungsten carbide, etc. , and the particle size of these hard microparticles (55) is 1500~30000 mesh of the international mesh standard [MESH], and these hard microparticles (55) can stick to the high-speed rotating centrifugal force and high-speed ejection etc. on the surface of the soft elastic carrier (50) [as shown in (B) of the third figure] for high-speed spraying by the spraying equipment;

The physical dry surface treatment method of the semiconductor wafer of the present invention is shown in Figures 3 and 4. The feature of the present invention is that the surface treatment comprises a method for spraying the surface treatment composition at a specific spray angle to remove a semiconductor wafer. The step of the surface to be treated (105) of the circle (100) is carried out, wherein the surface treatment composition (500) comprises a soft elastic carrier (50) with hard microparticles (55) adhered to the surface, and the specific angle is 2 to 60 degrees, and the surface treatment composition (500) is ejected at a speed of 50m/s~200m/s, so that the surface treatment composition (500) and the surface to be treated (105 of the semiconductor wafer (100) ) during high-speed contact, as shown in the fifth figure, the soft elastic carrier (50) will deform and form high-speed friction and sliding on the surface to be treated (105). (50) Hard particles (55) are adhered and adsorbed on the surface, so that they can produce a grinding effect with respect to the to-be-processed surface (105) of the semiconductor wafer (100), thereby generating and removing the to-be-processed surface (105) of the semiconductor wafer (100). 105) of the coating or the effect of the polished surface to be treated (105);

And according to some embodiments, the present invention can be based on the composition of surface treatment The material (500) selects hard particles (55) of different materials (such as diamond, boron nitride, tungsten carbide or their mixtures) or different particle sizes (such as 5000, 10000 or 15000 mesh), and can be used to remove semiconductor wafers ( 100) coating of different materials on the surface to be treated (105), and further can achieve the thinning effect of thinning the semiconductor wafer (100) (for example, selecting hard particles (55) with a mesh size of about 10,000), or for semiconductor wafer (100) thinning Flattening or mirror polishing of the surface (105) of the wafer (100) to be processed (for example, selecting hard particles (55) with a mesh number of 20,000).

Furthermore, according to some embodiments, the present invention can further depend on the state of the surface (105) of the semiconductor wafer (100) to be processed, such as the semiconductor wafer (100) without coating, with coating (such as insulating coating or metal coating) ], and choose to carry out two or more blasting surface treatment steps, and the particle size of the hard particles (55) of the surface treatment composition (500) in each blasting surface treatment step is different, or according to the manufacturer's The surface to be processed (105) of the semiconductor wafer (100) has different thickness requirements, and multiple processing steps such as rough removal, fine removal and fine polishing are sequentially performed to meet the requirements of processing speed and processing accuracy. Of course, the method of the present invention can also be applied in combination with typical processes such as etching, chemical mechanical polishing, or cleaning before and after the process according to the process requirements of the semiconductor wafer (100).

Also, according to some embodiments, the semiconductor wafer ( 100 ) of the present invention may further be a sapphire substrate, a glass substrate or a quartz substrate for removing the coating film or polishing the surface.

As can be seen from the above, the characteristic of the physical dry surface treatment method for semiconductor wafers of the present invention is that, as shown in Figures 4, 5 and 6, it utilizes soft The action of the surface treatment composition of the elastic carrier (50) and the hard microparticles (55) to blast away the surface to be treated (105) of the semiconductor wafer (100), when the soft surface treatment composition (500) When the elastic carrier (50) is in high-speed contact with the surface to be treated (105), the soft elastic carrier (50) itself will deform and cause frictional sliding on the surface of the workpiece (as shown in the fifth figure), and use the friction to make the soft elastic The hard particles (55) on the surface of the carrier (50) are removed or polished, so that the surface residues (60) are scraped off [as shown in (A) of the fifth figure]. In terms of the chemical mechanical polishing technology, not only the process is extremely simple and fast, but also corrosive liquids (such as hydrofluoric acid) are not required to avoid the generation of toxic gases during the process, which greatly improves the safety of the process. In addition, there will be no waste such as waste grinding liquid, grinding sludge, etc., which reduces the damage to the ecological environment, thereby reducing the cost of equipment and manpower required for the recycling and processing of chemical waste liquid, so that the present invention can simplify the regeneration. The surface treatment process of the wafer can improve the processing fineness and the speed of surface treatment.

At the same time, it can reduce the pollution of chemicals, not only save the procedures and equipment of waste liquid treatment, so that the regenerated wafer process can be more environmentally friendly and safe. In addition, the metamorphic layer of the semiconductor wafer (100) during regeneration can be reduced, thereby improving the yield of the overall process.

To sum up, it can be understood that the present invention is an invention with excellent creativity, in addition to effectively solving the problems faced by habitual practitioners, it also greatly improves the efficacy, and there is no identical or similar product creation or product creation in the same technical field. Open use, and at the same time have the improvement of efficacy, so the present invention has been in line with the "novelty" and "progressive" of the invention patent. The requirement of “step-by-step” is to apply for an invention patent in accordance with the law.

100: Semiconductor Wafers

105: Surface to be treated

500: Composition for Surface Treatment

Claims (9)

A composition for surface treatment of a semiconductor wafer, the composition for surface treatment comprises a series of soft elastic carriers and a series of hard microparticles, wherein the soft elastic carriers are made of elastic materials with adhesion, and the The particle size of the soft elastic carrier is 10um~150um, and the particle size of these hard particles is 1500~30000 mesh of the international mesh standard [MESH]; so that these hard particles can be stained during high-speed rotation centrifugal force and ejection. Adhered to the surfaces of the soft elastic carriers, a surface to be processed of a semiconductor wafer is sprayed and removed by a spraying device. The composition for surface treatment of semiconductor wafers as claimed in claim 1 of the scope of the application, wherein the soft elastic carriers are selected from soft elastic composites made of plastic, rubber or silicone as the base material. The composition for surface treatment of semiconductor wafers as claimed in claim 1 of the scope of the application, wherein the hard particles can be selected from natural diamonds, synthetic diamonds or mixtures thereof. The surface treatment composition for a semiconductor wafer as claimed in claim 1 of the scope of the application, wherein the hard particles can be selected from boron nitride, boron carbide or mixtures thereof. The surface treatment composition for a semiconductor wafer as claimed in claim 1 of the scope of the application, wherein the hard particles can be selected from tungsten carbide or a mixture thereof. A physical dry surface treatment method of a semiconductor wafer, comprising a step of spraying the surface treatment composition to remove the surface to be treated of a semiconductor wafer at a specific spray angle, wherein the surface treatment composition is an application The one described in any one of Claims 1 to 5 of the scope of the patent, and the speed of the surface treatment composition ejection is 50m/s~200m/s; so that the surface treatment composition and the surface to be treated of the semiconductor wafer are During high-speed contact, the soft elastic carrier will deform and form high-speed friction and sliding on the surface to be treated, and because the surface of the soft elastic carrier adheres and adsorbs hard particles, it can produce a grinding effect relative to the surface to be treated, thereby generating removal or polishing of the semiconductor The effect of the wafer surface to be processed. The physical dry surface treatment method of a semiconductor wafer as claimed in claim 6 of the scope of the application, wherein the specific angle is 2 degrees to 60 degrees. The physical dry surface treatment method for semiconductor wafers as claimed in claim 6 of the scope of the application, wherein the surface treatment method can be selected to perform two or more passes, and the surface treatment composition of each blasting surface treatment step is hard The particle sizes of the microparticles are different, and are used for the processing steps of rough removal, fine removal and fine polishing in sequence. The method for physical dry surface treatment of a semiconductor wafer according to claim 6 of the scope of the application, wherein the semiconductor wafer can be a sapphire substrate, a glass substrate or a quartz substrate.

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