WO2008111729A1

WO2008111729A1 - Method of thinning substrate, apparatus for thinning substrate and system having the same

Info

Publication number: WO2008111729A1
Application number: PCT/KR2008/000497
Authority: WO
Inventors: Ki-Jeong Lee; Sang-Hoon Kim; Kwang-Chul Lee; Jeong-Min Kim
Original assignee: Innoroot Co., Ltd.
Priority date: 2007-03-09
Filing date: 2008-01-28
Publication date: 2008-09-18
Also published as: KR20080082846A

Abstract

A method of thinning a substrate is described. According to the method, a substrate having a front surface, on which a circuit pattern is formed, and to which a protection tape is attached, is horizontally secured so that a rear surface of the substrate is exposed. An amount of an etching solution to be supplied is determined based on a predetermined etching thickness of the substrate. The substrate is dipped in the etching solution. The substrate is rotated to reduce the thickness of the substrate. Thus, a substrate may be uniformly thinned, and manufacturing costs may be reduced.

Description

METHOD OF THINNING SUBSTRATE, APPARATUS FOR THINNING SUBSTRATE AND SYSTEM HAVING THE SAME

Technical Field The present invention relates to a method of thinning a substrate, an apparatus for thinning a substrate and a system having the apparatus for thinning a substrate. More particularly, the present invention relates to a method of thinning a substrate for etching a surface of a substrate such as a semiconductor wafer so as to thin the substrate, an apparatus for thinning a substrate and a system having the apparatus for thinning a substrate.

Background Art

Nowadays, research is being conducted on a semiconductor device having a multilayer structure so as to improve processing rate, memory capacitance, etc. In order to manufacture the semiconductor device having a multilayer structure, a semiconductor wafer needs to be thinned.

Conventional methods for thinning a substrate include a method of mechanically polishing a surface of a substrate. However, when a substrate is thinned through mechanical polishing, the substrate may be damaged through a polishing process.

Thus, a chemical mechanical polishing (CMP) method using slurry, a dry polishing method using a plasma gas, a spin-etching method using an etching solution, etc. are recently used. However, when a substrate is thinned through the CMP method, the polishing rate of the substrate is low. Furthermore, it is difficult to thin the substrate to have a thickness less than about 75 μm. Thus, the CMP method may not be practically appropriate. When a substrate is thinned through the dry polishing method, heat generated by high-speed friction may cause damage to a circuit, and the substrate may have a damaged layer due to mechanical processing. Furthermore, the substrate may be also damaged by a plasma gas. When a substrate is thinned through the etching method using an etching solution, the etching solution used for thinning a substrate may be difficult to reuse, and thus costs for the etching solution may be high.

Disclosure of the Invention Technical Problem

The present invention provides a method of thinning a substrate, which is capable of uniformly thinning a substrate and minimizing an amount of an etching solution. Furthermore, the present invention provides an apparatus for thinning a substrate so as to perform the above-mentioned method of thinning a substrate.

Furthermore, the present invention provides a system having the above-mentioned apparatus for thinning a substrate. Technical Solution According to a method of thinning a substrate according to an example embodiment of the present invention, a substrate having a front surface, on which a circuit pattern is formed, and to which a protection tape is attached, is horizontally secured so that a rear surface of the substrate is exposed. An amount of an etching solution to be supplied is determined based on a desired etching thickness of the substrate. The substrate is dipped in the etching solution. The substrate is rotated to etch the rear surface of the substrate.

The amount of the etching solution may increase as the desired etching thickness of the substrate increases, and the amount of the etching solution may decrease as the desired etching thickness of the substrate decreases. Preferably, the substrate may be cleaned and dried.

The etching solution may include at least one selected from the group consisting of a fluoride salt, a nitrate, sulfuric acid and phosphoric acid, and the substrate may be rotated at about 10 to about 200 rpm while the substrate is etched. An apparatus for thinning a substrate according to an example embodiment of the present invention includes a securing part, an etching chamber and an etching solution supply part. The securing part secures a substrate having a front surface, on which a circuit pattern is formed, and to which a protection tape is attached, to expose a rear surface of the substrate, the securing part being capable of rotating the substrate. The etching chamber receives an etching solution. The etching solution supply part provides an etching solution having an amount determined based on a desired etching thickness of the substrate. Preferably, the securing part may include a chuck, on which the substrate is disposed, a vacuum suction member providing vacuum to the chuck and a rotation member providing driving power to the chuck to rotate the chuck.

The apparatus for thinning a substrate may further include a cleaning part spraying deionized water to the substrate and a drying part spraying dry air or nitrogen gas to the substrate. Furthermore, the apparatus for thinning a substrate may further include a cooling part to control the temperature of the etching solution.

A system for thinning a substrate according to an example embodiment of the present invention includes a grinding apparatus, an etching apparatus and a first transferring apparatus. The grinding apparatus includes a first securing part and a grinder. The first securing part secures a substrate having a front surface, on which a circuit pattern is formed, and to which a protection tape is attached, to expose a rear surface of the substrate, the first securing part being capable of rotating the substrate. The grinder grinds the rear surface of the substrate to thin the substrate. The etching apparatus includes a second securing part, an etching chamber receiving an etching solution and an etching solution supply part. The second securing part secures the substrate to expose the rear surface of the substrate, the second securing part being capable of rotating the substrate. The etching solution supply part provides an etching solution having an amount determined based on a desired etching thickness of the substrate. The first transferring apparatus transfers the substrate from the grinding apparatus to the etching apparatus.

Preferably, the system for thinning a substrate may further include a ring frame mounting apparatus and a second transferring apparatus. The ring frame mounting apparatus includes a third securing part securing the substrate to expose the rear surface of the substrate and a ring frame disposed to surround the substrate secured by the third securing part, the ring frame being capable of being released from the third securing part. The second transferring apparatus transfers the substrate from the etching apparatus to the ring frame mounting apparatus.

According to the above, a substrate may be uniformly thinned, and manufacturing costs may be reduced. Furthermore, manufacturing efficiency may be improved.

Brief Description of the Drawings

FIG. 1 is a flowchart illustrating a method of thinning a substrate according to an example embodiment of the present invention.

FIGS. 2, 3, 4 and 5 are schematic cross-sectional views illustrating an apparatus for thinning a substrate according to an example embodiment of the present invention and explaining the operation of the apparatus.

FIG. 6 is a schematic plan view illustrating a system for thinning a substrate according to an example embodiment of the present invention.

FIG. 7 is a schematic view illustrating a grinding apparatus illustrated in FIG. 6.

FIG. 8 is a schematic view illustrating a grinding apparatus illustrated in FIG. 6.

FIG. 9 is a schematic view illustrating a substrate combined with a ring frame. ^Description of reference numerals of the main elements in drawings* 100, 400: apparatus for thinning a substrate 200: grinding apparatus 300: first transferring apparatus 500: second transferring apparatus 600: ring frame mounting apparatus

Best Mode for Carrying Out the Invention

Hereinafter, a method of thinning a substrate according to an example embodiment of the present invention will be described more fully. Method of thinning a substrate

According to a method of thinning a substrate according to an example embodiment of the present invention, a substrate having a front surface, on which a circuit pattern is formed, and to which a protection tape is attached, is horizontally secured so that a rear surface of the substrate is exposed. An amount of an etching solution to be supplied is determined based on a predetermined etching thickness of the substrate. The substrate is dipped in the etching solution. The substrate is rotated to reduce the thickness of the substrate.

Firstly, a substrate having a protection tape is prepared. For example, the substrate may be a semiconductor wafer substrate having a front surface, on which a circuit pattern is formed. The protection tape serves to protect the circuit pattern. Thereafter, the substrate is horizontally secured (step SlO). For example, the substrate may be secured by a porous chuck using the negative pressure of vacuum. Particularly, the porous chuck may make contact with the protection tape of the substrate to secure the substrate.

The substrate is dipped in an etching solution for etching (step S20). For example, the substrate may be disposed in a receiving container, and an etching solution may be provided into the receiving container. While the etching solution is provided, the substrate is preferably rotated so that the substrate may be uniformly etched. An amount of the etching solution is determined based on a desired etching thickness of the substrate. The etching thickness of the substrate represents a thickness of a portion of the substrate, which is removed by etching. For example, as the etching thickness of the substrate increases, the amount of the etching solution used for etching may increase. As the etching thickness of the substrate decreases, the amount of the etching solution used for etching may decrease. The amount of the etching solution may vary based on a material of the substrate and the etching ratio of the etching solution. Examples of the etching solution may include a fluoride salt, a nitrate, sulfuric acid, phosphoric acid, etc. in view of etching efficiency. These may be used alone or in a combination thereof.

The substrate dipped in the etching solution rotates (step S30) so as to increase an etching speed and etching uniformity. For example, the substrate may be rotated at about 10 to about 200 rpm. When the rotation speed of the substrate is less than about 10 rpm, uniform etching of the substrate may be difficult to achieve. When the rotation speed of the substrate is more than about 200 rpm, the substrate may spin unstably and uniform etching of the substrate may be difficult to achieve since the etching solution moves to an edge of the substrate. After the substrate is etched, a cleaning solution such as deionized water may be provided to the substrate for cleaning the substrate, and a gas may be provided to the substrate for drying the substrate (step S40). Examples of the gas may include air, nitrogen gas, etc. While the substrate is cleaned or dried, the substrate is preferably rotated, for example, at about 300 to about 2,000 rpm.

The substrate is preferably secured horizontally in view of manufacturing efficiency while the substrate is thinned and cleaned. After the substrate is thinned and cleaned, the substrate may be attached to a thinning tape (or a dicing tape) for easily performing following processes such as a dicing process.

The method of thinning a substrate according to an example embodiment of the present invention may be sequentially performed with a grinding process, a ring mounting process, etc.

The method of thinning a substrate according to an example embodiment of the present invention uses a proper amount of an etching solution depending on a desired etching thickness of a substrate so that the amount of the etching solution used may be minimized. Thus, manufacturing costs may be reduced. Furthermore, the substrate is etched while being horizontally secured so that etching uniformity and manufacturing efficiency may be improved.

Hereinafter, an apparatus for thinning a substrate according to an example embodiment of the present invention will be described more fully with reference to the accompanying drawings.

Apparatus for thinning a substrate

Referring to FIGS. 2 to 5, an apparatus for thinning a substrate 100 according to an example embodiment of the present invention includes a first securing part 120, an etching chamber receiving an etching solution 130 and an etching solution supply part 140. The first securing part 120 secures a substrate 110 having a front surface, on which a circuit pattern is formed, and to which a protection tape 112 is attached, so that a rear surface of the substrate 110 is exposed. Furthermore, the first securing part 120 is capable of rotating the substrate 110. The etching solution supply part 140 provides an etching solution having a predetermined amount determined based on a desired etching thickness of the substrate 110.

For example, the substrate 110 may be a semiconductor wafer substrate having a front surface, on which a circuit pattern is formed. A protection tape 112 is attached to the substrate 110 so that the circuit pattern may not be damaged while the substrate 110 is etched.

The first securing part 120 may include a chuck 122, on which the substrate 110 is disposed, a vacuum suction member 124 providing vacuum to the chuck 122 and a rotation member 126 providing driving power to the chuck 122 to rotate the chuck 122. Vacuum is provided to the chuck 122, and the chuck 122 makes contact with the protection tape 112 to secure the substrate 110. The chuck 122 is preferably a porous chuck so as to easily secure the substrate 110. The first securing part 120 is preferably capable of moving in and out of the etching chamber 130.

The etching chamber 130 receives the etching solution. The substrate 110 is etched in the etching chamber 130.

The etching chamber 130 further includes an outlet 132 to exhaust the etching solution. After the substrate is etched, the etching solution moves out of the etching chamber 130 through the outlet 132. The apparatus for thinning a substrate 100 may further include a gate member 150 to control the outlet 132 to be opened.

The apparatus for thinning a substrate 100 may further include a cleaning part 160 providing a cleaning solution to the substrate 110 and a drying part 170 providing a dry gas to the substrate 110. The cleaning solution and the dry gas may be sprayed through the same nozzle. The apparatus for thinning a substrate 100 may further include an outer chamber 180 surrounding the etching chamber 130. The outer chamber 180 may be spaced apart from the etching chamber 130 by a predetermined distance, and the cleaning solution may be exhausted through an empty space between the etching chamber 130 and the outer chamber 180. Furthermore, the apparatus for thinning a substrate 100 may further include a cooling part (not shown) to prevent the etching solution from being excessively heated. When the substrate is etched, the etching solution may be excessively heated, for example, by reaction with the substrate so that an etching process is not stably controlled. The cooling part controls the temperature of the etching solution, thereby improving the stability of the etching process.

Hereinafter, the operation of an apparatus for thinning a substrate according to an example embodiment of the present invention will be described more fully. Referring to FIG. 2, the substrate 110 having the front surface, on which the circuit pattern is formed, and to which a protection tape 112 is attached, is secured on the chuck 122 of the first securing part 120 so that the rear surface of the substrate 110 is exposed. Particularly, the chuck 122 makes contact with the protection tape 112 to secure the substrate 110. When the substrate 110 is secured, the first securing part 120 moves the chuck 120 into the etching chamber 130 so that the substrate 110 is disposed in the etching chamber 130.

Referring to FIG. 3, an etching solution is provided into the etching chamber 130. An amount of the etching solution may depend on a desired etching thickness of the substrate 110. For example, as the etching thickness of the substrate increases, the amount of the etching solution used for etching may increase. Examples of the etching solution may include a fluoride salt, a nitrate, sulfuric acid, phosphoric acid, etc. in view of etching efficiency. These may be used alone or in a combination thereof. When the etching solution is provided, the outlet 132 of the etching chamber 130 is closed by the gate member 150 so that the etching solution may remain in the etching chamber 130. Preferably, the substrate 110 is rotated by the chuck 122 until etching the substrate is completed. For example, the substrate 110 may be rotated at about 10 to about 200 rpm.

Referring to FIG. 4, after the substrate 110 is etched, the outlet 132 is opened by the gate member 150. Accordingly, the etching solution is exhausted. Furthermore, the chuck 122 moves upward so that the substrate 110 is separated from the etching solution quickly.

A cleaning solution such as deionized water is provided to the substrate 110 by the cleaning part 160. After the substrate 110 is cleaned, a dry gas is provided to the substrate 110 by the drying part 170. The cleaning solution may be exhausted through an empty space between the etching chamber 130 and the outer chamber 180. While the substrate 110 is cleaned or dried, the substrate 110 is preferably rotated, for example, at about 300 to about 2,000 rpm. Referring to FIG. 5, the substrate 110 is secured by a second securing part

190. Particularly, the rear surface of the substrate 110 makes contact with a chuck 192 of the second securing part 190 so that the substrate 110 may be secured by the second securing part 190. Thus, the substrate 110 is separated from the first securing part 190 so that the protection tape 112 is exposed. The second securing part 190 may include the chuck 102 making contact with the substrate 110, a vacuum suction member 194 providing vacuum to the chuck 192 and a rotation member 196 providing driving power to the chuck 192 to rotate the chuck 192.

While the substrate 110 is etched, impurities may remain adjacent to the protection tape 112. Thus, the protection tape 112 is preferably cleaned and dried by the clean part 160 and the drying part 170, respectively.

After the substrate 110 is cleaned and dried, the substrate 110 may be transferred to the first securing part 120 and then transferred to an apparatus for following processes. The apparatus for thinning a substrate according to an example embodiment of the present invention uses a proper amount of an etching solution depending on a desired etching thickness of a substrate so that the amount of the etching solution used may be minimized. Thus, manufacturing costs may be reduced. Furthermore, the substrate is etched while being horizontally secured, and an etching process, a cleaning process and a drying process are performed in the same chamber so that manufacturing efficiency may be improved.

Hereinafter, a system for thinning a substrate according to an example embodiment of the present invention will be described more fully with reference to the accompanying drawings.

System for thinning a substrate

FIG. 6 is a schematic plan view illustrating a system for thinning a substrate according to an example embodiment of the present invention. Referring to FIG. 6, a system for thinning a substrate 1000 may include a grinding apparatus 200, a first transferring apparatus 300, an etching apparatus 400, a second transferring apparatus 500 and a ring frame mounting apparatus 600.

FIG. 7 is a schematic view illustrating a grinding apparatus illustrated in FIG. 6. Referring to FIG. 7, the grinding apparatus includes a securing part 210 and a grinder 220. The securing part 210 includes a chuck 212, on which a substrate 20 is disposed, a vacuum suction member 214 providing vacuum to the chuck 212 and a rotation member 216 providing driving power to the chuck 212 to rotate the chuck 212. A circuit pattern is formed on a front surface of the substrate 20, and a protection tape 22 is attached to the front surface to protect the circuit pattern. The securing part 210 secures the front surface of the substrate 20 by using vacuum suction so that a rear surface of the substrate 20 is exposed.

The grinding apparatus 200 grinds the rear surface of the substrate 20 to thin the substrate 20. The substrate 20 may be thinned to have a uniform thickness. Alternatively, the substrate 20 may be thinned to have a varying thickness so as to previously compensate for the substrate 20 being non-uniformly etched in a following etching process using an etching solution. For example, the substrate 20 may be thinned so that a central portion of the substrate 20 may be thinner than a peripheral portion of the substrate 20. The substrate 200 is preferably grinded so that the substrate 200 may not be damaged. For example, the substrate 200 may be grinded to have a thickness of about 75 to about 100 μm. After the substrate 20 is thinned by the grinding apparatus 200, the substrate 200 is transferred to the etching apparatus 400 by the first transferring apparatus 300. The first transferring apparatus 300 may include a securing part. The securing part includes a chuck, on which the substrate 20 is disposed, and a vacuum suction member providing vacuum to the chuck. The substrate 20 transferred to the etching apparatus may be etched, cleaned and dried. The etching apparatus is substantially the same as the apparatus for thinning a substrate according to an example embodiment of the present invention, which is described with reference to FIGS. 2 to 5. Thus, any explanation concerning constitution and operation will be omitted. The substrate 20 etched by the etching apparatus 400 is transferred to the ring frame mounting apparatus 600 by the second transferring apparatus 500.

After the substrate 20 is thinned and cleaned, a thinning tape (or a dicing tape) is preferably attached to the substrate 20 for handling the substrate and for easily performing following processes. The ring frame mounting apparatus 600 attaches a thinning tape to the substrate 20.

FIG. 8 is a schematic view illustrating a grinding apparatus illustrated in FIG. 6. FIG. 9 is a schematic view illustrating a substrate combined with a ring frame. Referring to FIGS. 8 and 9, the ring frame mounting apparatus 600 includes a securing part 610 and a ring frame 620. The securing part 610 receives the substrate 20 from the second transferring apparatus 500 and secures the substrate 20. The ring frame 620 is disposed to surround the substrate 20 secured by the securing part 610. The ring frame is capable of being released from the securing part 6210. The ring frame is combines with a thinning tape 622. The securing part 610 may include a chuck 612, on which the substrate 20 is disposed, securing the substrate 20 and a vacuum suction member 614 providing vacuum to the chuck. The chuck 612 makes contact with the protection tape 22 of the substrate 20 to secure the substrate 20 so that the rear surface of the substrate 20 is exposed. The ring frame mounting apparatus 600 attach the thinning tape 622 to the rear surface of the substrate 20 so that the substrate 20 may be maintained in a tensive state by the ring frame 620 and the thinning tape 622 and may be easily handled. Furthermore, the protection tape

22 may be removed from front surface of the substrate 20, and following processes may be performed.

According to the system for thinning a substrate according to an example embodiment of the present invention, an amount of an etching solution used may be minimized. Thus, manufacturing costs may be reduced. Furthermore, a semiconductor wafer having a thickness of about 5 to about 50 μήi may be manufactured through sequential processes.

Industrial Applicability

As described above, a substrate may be uniformly thinned, and costs for thinning a substrate may be reduced. Furthermore, manufacturing efficiency may be improved.

Although the exemplary embodiments of the present invention have been described, it is understood that the present invention should not be limited to these exemplary embodiments but various changes and modifications can be made by one ordinary skilled in the art within the spirit and scope of the present invention as hereinafter claimed.

Claims

1. A method of thinning a substrate, the method comprising: horizontally securing a substrate having a front surface, on which a circuit pattern is formed, and to which a protection tape is attached, so that a rear surface of the substrate is exposed; determining an amount of an etching solution to be supplied based on a desired etching thickness of the substrate; dipping the substrate in the etching solution; and rotating the substrate to etch the rear surface of the substrate.

2. The method of claim 1, further comprising: cleaning the substrate; and drying the substrate.

3. The method of claim 1, wherein the etching solution comprises at least one selected from the group consisting of a fluoride salt, a nitrate, sulfuric acid and phosphoric acid.

4. The method of claim 1, wherein the substrate rotates at 10 to 200 rpm.

5. The method of claim 1, wherein determining the amount of the etching solution increases the amount of the etching solution as the desired etching thickness of the substrate increases, and decreases the amount of the etching solution as the desired etching thickness of the substrate decreases.

6. An apparatus for thinning a substrate, the apparatus comprising: a securing part securing a substrate having a front surface, on which a circuit pattern is formed, and to which a protection tape is attached, to expose a rear surface of the substrate, the securing part being capable of rotating the substrate; an etching chamber receiving an etching solution; and an etching solution supply part providing an etching solution having an amount determined based on a desired etching thickness of the substrate.

7. The apparatus of claim 6, wherein the securing part includes a chuck, on which the substrate is disposed, a vacuum suction member providing vacuum to the chuck and a rotation member providing driving power to the chuck to rotate the chuck.

8. The apparatus of claim 6, further comprising: a cleaning part spraying deionized water to the substrate; and a drying part spraying dry air or nitrogen gas to the substrate.

9. The apparatus of claim 6, further comprising a cooling part to control the temperature of the etching solution.

10. The apparatus of claim 6, wherein the etching solution comprises at least one selected from the group consisting of a fluoride salt, a nitrate, sulfuric acid and phosphoric acid.

11. A system for thinning a substrate, the system comprising: a grinding apparatus including a first securing part and a grinder, the first securing part securing a substrate having a front surface, on which a circuit pattern is formed, and to which a protection tape is attached, to expose a rear surface of the substrate, the first securing part being capable of rotating the substrate, and the grinder grinding the rear surface of the substrate to thin the substrate; an etching apparatus including a second securing part, an etching chamber receiving an etching solution and an etching solution supply part, the second securing part securing the substrate to expose the rear surface of the substrate, the second securing part being capable of rotating the substrate, and the etching solution supply part providing an etching solution having an amount determined based on a desired etching thickness of the substrate; and a first transferring apparatus to transfer the substrate from the grinding apparatus to the etching apparatus.

12. The system of claim 11, wherein each of the first and securing parts comprises a chuck, on which the substrate is disposed, a vacuum suction member providing vacuum to the chuck and a rotation member providing driving power to the chuck to rotate the chuck, and the first transferring apparatus secures the substrate by vacuum suction.

13. The system of claim 11, wherein the etching solution further comprises: a cleaning part spraying deionized water to the substrate; and a drying part spraying dry air or nitrogen gas to the substrate.

14. The system of claim 11, wherein the etching solution comprises at least one selected from the group consisting of a fluoride salt, a nitrate, sulfuric acid and phosphoric acid.

15. The system of claim 11, further comprising: a ring frame mounting apparatus including a third securing part securing the substrate to expose the rear surface of the substrate and a ring frame disposed to surround the substrate secured by the third securing part, the ring frame being capable of being released from the third securing part; and a second transferring apparatus to transfer the substrate from the etching apparatus to the ring frame mounting apparatus.