Researchers Submit Patent Application, "Method and Apparatus for Processing a Substrate", for Approval (USPTO 20180179656)

Electronics Newsweekly |

By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Okuzono, Takahisa (Tokyo, JP); Fujikata, Jumpei (Tokyo, JP), filed on , was made available online on .

No assignee for this patent application has been made.

News editors obtained the following quote from the background information supplied by the inventors: "Plating technology is employed, for example, to deposit a metal in fine interconnect trenches or holes, or resist openings formed in a surface of a wafer, or to form bumps (protruding electrodes), which are to be electrically connected to package electrodes or the like, on a surface of a substrate. Plating technology is also employed to fill a metal into via holes in the production of an interposer or a spacer which has a large number of via plugs vertically penetrating therethrough and which is to be used in so-called three-dimensional packaging of semiconductor chips.

"For example, it is common practice in TAB (Tape Automated Bonding) or flip chip to form protruding connection electrodes (bumps) of gold, copper, solder or nickel, or of multiple layers of such metals at predetermined portions (electrodes) of the surface of a semiconductor chip, having interconnects formed therein, so that the semiconductor chip can be electrically connected via the bumps to package electrodes or TAB electrodes.

"Electroplating of a wafer is performed by applying a voltage between an anode and the wafer, which serves as a cathode, while keeping them immersed in a plating solution. In order to enable the plating solution to easily enter recesses or through-holes formed in the wafer surface, the wafer is subjected to a pre-wetting treatment which is to replace air, existing in the recesses or through-holes, with a pre-wetting liquid. The pre-wetting treatment is performed by immersing the wafer in the pre-wetting liquid held in a pre-wetting tank (see, for example, Japanese Patent No. 4664320).

"However, in the above-described conventional pre-wetting treatment, the entire wafer is immersed in the pre-wetting liquid. Therefore, it is necessary to use a large amount of pre-wetting liquid. In addition, it takes considerable time to fill the pre-wetting liquid into the pre-wetting tank, and to discharge the pre-wetting liquid from the pre-wetting tank.

"In order to solve such problems, a spray-type pre-wetting treatment has been proposed which involves spraying a pre-wetting liquid onto a wafer surface. However, the pre-wetting liquid with a high pressure can cause collapse of patterns formed on the water. With such a background, there is a demand for a soft pre-wetting technique which does not cause pattern collapse."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "According to embodiments, there are provided a method and apparatus which can perform a soft pre-wetting treatment of a substrate, such as a wafer, with use of a pre-wetting liquid in a smaller amount as compared to the conventional pre-wetting treatment.

"Embodiments, which will be described blow, relate to a method and an apparatus for replacing air in recesses or through-holes (e.g., via holes, trenches, resist openings, etc.), formed in a surface of a substrate such as a wafer, with a pre-wetting liquid by bringing the pre-wetting liquid into contact with the surface of the substrate prior to performing plating of the substrate.

"In an embodiment, there is provided a method of processing a surface of a substrate while holding the substrate with a substrate holder including a first holding member and a second holding member, the second holding member having an opening, said method comprising: holding the substrate with the substrate holder by sandwiching the substrate between the first holding member and the second holding member, with the surface of the substrate being exposed through the opening of the second holding member, and pressing a sealing ridge of the substrate holder against a peripheral portion of the substrate; pressing a sealing block against the substrate holder to cover the sealing ridge, thereby forming an external space defined by the substrate holder, the exposed surface of the substrate, and the sealing block; forming a vacuum in the external space; performing a seal inspection to check a sealed state provided by the sealing ridge based on a change in pressure in the external space; and performing a pre-wetting treatment by supplying a pre-wetting liquid to the external space while evacuating air from the external space to bring the pre-wetting liquid into contact with the exposed surface of the substrate.

"In an embodiment, the seal inspection and the pre-wetting treatment are performed successively in a pre-wetting tank.

"In an embodiment, the seal inspection and the pre-wetting treatment are performed while keeping the substrate holder, holding the substrate, in a vertical position.

"In an embodiment, the method further comprises: re-forming a vacuum in the external space after the seal inspection and before the pre-wetting treatment; and checking a sealed state provided by the sealing block based on a change in pressure in the external space.

"In an embodiment, the method further comprises: discharging the pre-wetting liquid from the external space after the pre-wetting treatment; and then performing a pretreatment by supplying a pretreatment liquid to the external space to bring the pretreatment liquid into contact with the exposed surface of the substrate.

"In an embodiment, the seal inspection, the pre-wetting treatment, and the pretreatment are performed successively in a pre-wetting tank.

"In an embodiment, there is provided an apparatus for processing a surface of a substrate, comprising: a substrate holder configured to hold the substrate between a first holding member and a second holding member, the second holding member having an opening through which the surface of the substrate can be exposed, the substrate holder having a sealing ridge to be pressed against a peripheral portion of the substrate; a sealing block having a larger shape than the sealing ridge; an actuator configured to press the sealing block against the substrate holder; a vacuum line coupled to the sealing block; an on-off valve attached to the vacuum line; a processing controller configured to perform a seal inspection to check a sealed state provided by the sealing ridge based on a change in pressure in an external space formed by the substrate holder, the exposed surface of the substrate, and the sealing block; a pre-wetting liquid supply line coupled to the sealing block; and a pre-wetting liquid supply valve attached to the pre-wetting liquid supply line, wherein the processing controller is configured to keep the on-off valve and the pre-wetting liquid supply valve open simultaneously at least for a predetermined period of time.

"In an embodiment, the apparatus further comprises a pre-wetting tank in which the seal inspection is performed and to which the pre-wetting liquid is supplied.

"In an embodiment, the apparatus further comprises: a drain line coupled to the sealing block, the drain line communicating with the external space; and a pretreatment liquid supply line coupled to the sealing block, the pretreatment liquid supply line communicating with the external space.

"In an embodiment, the apparatus further comprises a plating tank configured to immerse the substrate, held by the substrate holder, in a plating solution to plate the substrate.

"In an embodiment, there is provided a non-transitory computer-readable storage medium that stores a program for causing a plating apparatus to perform a method of processing a surface of a substrate while holding the substrate with a substrate holder including a first holding member and a second holding member, the second holding member having an opening, said method comprising: holding the substrate with the substrate holder by sandwiching the substrate between the first holding member and the second holding member, with the surface of the substrate being exposed through the opening of the second holding member, and pressing a sealing ridge of the substrate holder against a peripheral portion of the substrate; pressing a sealing block against the substrate holder to cover the sealing ridge, thereby forming an external space defined by the substrate holder, the exposed surface of the substrate, and the sealing block; forming a vacuum in the external space; performing a seal inspection to check a sealed state provided by the sealing ridge based on a change in pressure in the external space; and performing a pre-wetting treatment by supplying a pre-wetting liquid to the external space while evacuating air from the external space to bring the pre-wetting liquid into contact with the exposed surface of the substrate.

"According to the above-described embodiments, the external space is formed between the exposed surface of the substrate held by the substrate holder and the sealing block. The pre-wetting liquid is supplied only to this external space. This makes it possible to significantly reduce the use of the pre-wetting liquid as compared to the conventional method. Furthermore, since the pre-wetting liquid is injected into the external space while evacuating air from the external space, the pre-wetting liquid can easily enter recesses or through-holes formed in the substrate, thereby expelling air from the recesses or through-holes."

For additional information on this patent application, see: Okuzono, Takahisa; Fujikata, Jumpei. Method and Apparatus for Processing a Substrate. Filed and posted . Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220180179656%22.PGNR.&OS=DN/20180179656&RS=DN/20180179656

Keywords for this news article include: Technology, Electronics, Semiconductor, Patent Application.

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