JP2002026049A - Surface treating method of substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface treating method of a substrate having irregularities on the surface (e.g. a semiconductor substrate having protruding insulating parts and recessed electrode parts formed on the surface being used in the formation of a metal film pattern) in which only the protrusions can be reformed selectively in the fabrication of a semiconductor device. SOLUTION: Properties at the surface part of protrusions on a substrate (A) are varied selectively by touching the surface part of a planar or sheet-like article (B) only to the surface part of protrusions on the substrate (A) having irregularities on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for treating a surface of a substrate. The substrate surface treatment method of the present invention is useful for the surface treatment of a semiconductor substrate. When manufacturing various electronic components, for example, semiconductor devices such as diodes, transistors, and LSIs, a metal film (UBM) is formed on a bump formation region.
Film; under bump metal).

[0002]

2. Description of the Related Art As a semiconductor device, a device having a metal electrode such as an aluminum electrode is known. A bump is formed on the aluminum electrode by solder or the like, but the solder and the aluminum electrode have poor wettability. Therefore, a metal film pattern is formed on the aluminum electrode by a metal film having good wettability with solder or the like.

The pattern formation of the metal film in the manufacture of a semiconductor device is generally performed by a pattern formation method using photolithography. However, the above-described pattern formation by photolithography has a problem in that the process cost of facilities and the like in the photolithography and etching steps is extremely high, and that wastewater treatment of an etching solution or the like is troublesome, thereby deteriorating the working environment.

Recently, as a method of forming the metal film pattern, a metal film having good wettability is provided on surfaces of an insulating portion and an electrode portion formed on a semiconductor substrate, and the insulating portion and the electrode for the metal film are provided. A method of forming a pattern by peeling and removing only a metal film on an insulating portion by using an adhesive sheet by utilizing a difference in adhesiveness with a portion has been proposed (JP-A-10-6).
No. 4912).

In such a method of forming a pattern using an adhesive sheet for peeling and removing a metal film, a metal film other than a portion on which a metal film is to be formed, for example, a metal film on an insulating portion is peeled and removed without leaving an adhesive sheet. Of the metal film is required. However, if the adhesion between the insulating film and the metal film is high, it has been difficult to remove and remove the metal film on the insulating portion in a completely patterned form.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device, which comprises forming a substrate having an uneven surface on its surface (for example, a convex insulating portion and a concave electrode portion used for forming a metal film pattern are formed on the surface). It is an object of the present invention to provide a surface treatment method for a substrate which can selectively modify only the projections of a semiconductor substrate or the like.

Another object of the present invention is to provide a method for forming a metal film pattern by using the method for treating a surface of a substrate.

[0008]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that the above-mentioned object can be achieved by the following method. Reached.

That is, according to the present invention, the surface of a flat or sheet-like article (B) is brought into contact only with the surface of a projection on a substrate (A) having an uneven surface.
The present invention relates to a method for treating a surface of a substrate, wherein a property of a surface portion of a convex portion on the substrate (A) is selectively changed.

According to the above method, by appropriately selecting the surface member of the article (B), a desired treatment can be performed only on the surface of the projection, and the properties of the surface of the projection and the surface of the depression can be discriminated. Can be

[0011] In the method for treating a surface of a substrate, a part of a surface member of the article (B) is transferred to a surface of a convex portion on the substrate (A) by contacting a surface of the article (B). Preferably.

According to the surface member of the article (B), the substrate (A)
Means for changing the property of the upper convex surface portion is not particularly limited, but according to the method of transferring the surface member of the article (B) to the convex surface portion on the substrate (A), The property change can be easily performed.

Transferring to the surface of the convex portion on the substrate (A);
Examples of the surface member of the article (B) include those containing a fluorine-containing resin.

By transferring the fluorine-containing resin to the surface of the convex portion on the substrate (A), the free energy of the surface portion of the convex portion can be reduced, and the surface of the convex portion on the substrate (A) can be reduced. Can be effectively weakened.

The surface member of the article (B) to be transferred to the surface of the convex portion on the substrate (A) may be one containing a fluorine adhesive substance.

The fluorine adhesive substance can be easily transferred to the surface of the convex portion on the substrate (A), can reduce the free energy of the surface portion, and adhere to the surface of the convex portion on the substrate (A). Sex can be effectively weakened.

In the method for treating a surface of a substrate, the substrate (A) having the uneven surface on which the surface treating method is applied is a semiconductor substrate having a convex insulating portion and a concave electrode portion formed on the surface. Especially useful in cases.

Further, the present invention provides a method of forming a metal film on the entire surface of a semiconductor substrate having a convex insulating portion and a concave electrode portion formed on a surface thereof, after performing the surface treatment method on the semiconductor substrate. After attaching the adhesive sheet to the entire surface of the outermost layer portion of the formed metal film, by performing a step of peeling the adhesive sheet, the metal film on the surface of the convex insulating portion is selectively peeled and removed. A method of forming a metal film pattern only on a concave electrode portion on a semiconductor substrate.

Only on the surface of the convex insulating portion on the semiconductor substrate,
By performing a certain kind of treatment (for example, the transfer treatment), it is possible to effectively weaken the adhesiveness between the convex insulating portion and a metal film to be formed thereafter, thereby removing the metal film. The performance is improved. On the other hand, regarding the concave electrode portion,
Since the surface treatment is not performed, the adhesion to the metal film does not decrease. By selectively treating only the convex insulating portions on the semiconductor substrate in this manner, a favorable result can be obtained in forming a metal film pattern using an adhesive sheet.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION In the semiconductor manufacturing process, a metal film pattern is formed on a substrate in a semiconductor manufacturing process by taking a case where a semiconductor substrate is used as a substrate (A) as an example of a method for treating a substrate according to the present invention. The method will be described in detail, but the method for treating the surface of a substrate of the present invention is not limited to these examples.

FIG. 1 is a cross-sectional view of a semiconductor substrate 1 in which a convex insulating portion 3 and a concave electrode portion 4 are formed, and a metal electrode pattern is formed on the electrode portion 4.

As the semiconductor substrate 1, there is a silicon substrate or the like. Further, a semiconductor element region 2 such as a diode or a transistor can be formed on the semiconductor substrate 1 of the present invention. The electrode part 4 is patterned to obtain conduction with the semiconductor element 2. The method of forming the insulating section 3 and the electrode section 4 on the semiconductor substrate 1 is not particularly limited, and can be formed by various methods. For example, the insulating section 3 and the electrode section 4 are formed by forming the insulating section 3 on the semiconductor substrate 1 by a CVD method or the like and then using photolithography.
It is formed by a method of patterning the insulating portion 3 and forming the electrode portion 4 at a necessary place. An aluminum electrode or the like is used as the electrode part 4, and silica, BP,
SG (Bolon Phosphorus Silicate Glass), PSG
(Phosphorus Silicate Glass), silicon nitride, polyimide and the like are used.

Next, as shown in FIG.
The surface treatment sheet 5 (plate-shaped or sheet-shaped article (B)) is brought into contact with only the surface of the upper insulating portion 3 and heated. Heating is performed by the heater 6. In FIG. 2, the heater 6 is provided only at the lower part of the semiconductor substrate 1, but the heater 6 can be provided at the upper part of the surface treatment sheet 5. As the heater 6, lamination using a hot plate or a heat roll is used. As a result, a part (small amount) of the surface treatment sheet 5 is transferred to the surface layer on the insulating portion 3 and the properties of the insulating portion 3 change.

As the surface treatment sheet 5, for example,
Fluorine-containing resins are preferably used. Examples of such a sheet include a sheet made of a general-purpose fluorine resin such as polytetrafluoroethylene, poly (chlorotrifluoroethylene), and polyvinylidene fluoride, but other sheets may be used. In addition, as the sheet 5 for surface treatment, an adhesive sheet 5 ′ in which a fluorine-based adhesive layer is provided on a sheet substrate can be used. The sheet substrate may be in a sheet shape or a tape shape. Examples of the sheet substrate include plastic films used for general adhesive sheets such as polyethylene, polypropylene, polyethylene terephthalate, and acetylcellulose.
For the adhesive layer, for example, various adhesive substances such as an acrylic polymer containing a fluorine atom are used. When the pressure-sensitive adhesive sheet 5 ′ is used as the surface treatment sheet 5,
The adhesive layer of the pressure-sensitive adhesive sheet 5 'is brought into contact with the contact surface side with the substrate.

In the method for forming a metal electrode pattern according to the present invention,
The above processing is performed on the semiconductor substrate 1, and the surface treatment sheet 5 is separated from the semiconductor substrate 1. Next, a metal film is provided on the surfaces of the insulating section 3 and the electrode section 4 formed on the semiconductor substrate 1. The metal film is an adhered portion of the adhesive sheet A for peeling and removing the metal film. The metal film 9 serving as an adherend is a film having good solder wettability, and specifically, gold, copper, silver, platinum, iron, tin,
It is formed using nickel, nickel-vanadium alloy, or the like. Among them, it is preferable to use gold (Au).

As shown in FIG. 3, the metal films 7 and
It is preferable to form three layers in which 8 and 9 are sequentially formed. First
The metal film 7 of the layer is a film for forming a good junction with the electrode part 4, and specifically, titanium, vanadium, chromium,
Thin films of cobalt, zirconium, aluminum, tantalum, tungsten, platinum, nitrides of these metals, and alloys containing these metals as main components are used. Among these, a titanium thin film is preferable. The second-layer metal film 8 is a film for adjusting the stress applied to the interface between the metal film 7 and the insulating portion 3, and specifically includes nickel, copper, palladium, and alloys containing these metals as main components. And the like. Among these, a nickel thin film is preferable. Due to the internal stress of the metal film 8 of the second layer, the adhesiveness at the interface between the metal film 7 and the insulating portion 3 is reduced, and the peeling and removal of the metal film by the adhesive sheet A is easier. Then, as the third layer, a metal film 9 having good solder wettability, which serves as a portion to be adhered to the adhesive sheet A, is provided.

Next, as shown in FIG. 4, an adhesive layer of an adhesive sheet A is attached to the metal film 9 provided on the surface of the insulating portion 3 and the electrode portion 4 formed on the semiconductor substrate 1. Peel off the adhesive sheet A. At the time of this peeling removal, the surface of the insulating portion 3 has good peelability at the interface with the metal film 7 by the surface treatment. On the other hand, since the interface between the electrode portion 4 and the metal film 7 has good adhesiveness, the interface is not removed by the adhesive sheet A. By this operation, the metal films 7, 8, on the surface of the insulating portion 3,
9 is selectively peeled off, and a desired metal electrode pattern is formed on the electrode portion 4 on the semiconductor substrate 1 as shown in FIG.

According to the metal electrode pattern forming method of the present invention, a metal electrode pattern having good wettability with bumps is reliably formed on the electrode portion 4 on the semiconductor substrate 1 as shown in FIG. The bumps can be easily formed on the metal electrode thus patterned, and the manufacturing process of the semiconductor device can be performed simply and at low cost.

The adhesive sheet A is obtained by forming an adhesive layer b on a sheet base material a. The adhesive sheet A is
Any of a sheet shape and a tape shape may be used.

Examples of the sheet substrate a include plastic films used for general adhesive sheets such as polyethylene, polypropylene, polyethylene terephthalate, and acetylcellulose. As the adhesive forming the adhesive layer, a base polymer applied to a general pressure-sensitive adhesive is used. Such base polymers include:
Any known various polymers such as an acrylic polymer and a rubber material can be used, but it is particularly preferable to use an acrylic polymer. A crosslinking agent and various additives can be appropriately blended in the adhesive layer.

[0031]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited thereto.

Reference Example 1 Acrylic polymer A (weight average molecular weight: 2.8 million, weight average molecular weight (Mw)) composed of a copolymer of 2-ethylhexyl acrylate / methyl acrylate / acrylic acid = 30/70/10 (weight ratio) (Number average molecular weight (Mn) = 22)
100 g of a 27% by weight toluene solution of dipentaerythritol hexaacrylate (manufactured by Nippon Synthetic Chemical; trade name:
UV3000B) 10 g and a polyisocyanate compound (Nippon Polyurethane Industry; trade name: Coronate L)
0.8 g of the adhesive composition (toluene solution)
It is applied on a film substrate made of a polyester film having a thickness of 50 μm, and dried in a drying oven at 130 ° C. for 3 times each
After drying for 30 minutes, an adhesive layer having a thickness of 35 μm was formed to prepare an adhesive sheet.

Example 1 A semiconductor substrate 1 having a surface provided with a convex insulating portion 3 and a concave electrode portion 4 as shown in FIG. 1 is prepared. In addition, the convex insulating portion 3 is a polyimide film, and the concave electrode portion 4 is an aluminum thin film.
Next, as shown in FIG. 2, a PTFE (polytetrafluoroethylene) plate having a thickness of 1 mm is brought into contact only with the protrusion insulating portion 3, and is sandwiched between a lower portion of the semiconductor substrate 1 and an upper portion of the PTFE by a hot plate. Crimping was performed at 150 ° C. and 10 kg / cm ² for 30 seconds. Thereafter, the PTFE plate was removed.

Subsequently, as shown in FIG. 3, after the metal films 7, 8, and 9 are provided on the semiconductor substrate 1, the adhesive sheet prepared in Reference Example 1 is rolled at 50 ° C. on the metal film. I stuck it. After that, heat and hold at this temperature for 1 minute,
Cooled to room temperature. After peeling the adhesive sheet,
Only the metal films 7, 8, and 9 on the insulating film 3 were peeled off together with the adhesive sheet, and a metal electrode pattern for bump connection was formed on the electrode portion 4.

Comparative Example 1 The same operation as in Example 1 was performed, except that the surface treatment for the PTFE plate was not performed. The metal film on the insulating portion 3 was only partially peeled and removed, and no metal electrode pattern was obtained.

Reference Example 2 Polymer A comprising a copolymer of 2-ethylhexyl acrylate / pentafluoroethyl acrylate / acrylic acid = 50/47/3 (weight ratio) (weight average molecular weight 300,000
Weight average molecular weight (Mw) / number average molecular weight (Mn) = 8)
And Nippon Polyurethane Industry Co., Ltd .; an adhesive composition (ethyl acetate solution) containing 3.2 g of a coronate L) was applied on a 100 μm-thick polyester film base material, and dried in a drying oven. ° C
For 3 minutes each to form an adhesive layer having a thickness of 5 μm to prepare an adhesive sheet for surface treatment.

Example 2 A semiconductor substrate 1 having a convex insulating portion 3 and a concave electrode portion 4 formed on the surface thereof as shown in FIG. 1 is prepared. In addition, the convex insulating portion 3 is a polyimide film, and the concave electrode portion 4 is an aluminum thin film.
Next, as shown in FIG. 2, the pressure-sensitive adhesive layer of the surface treatment adhesive sheet was brought into contact with only the convex insulating portion 3 and attached at 140 ° C. along a roll.

Subsequently, as shown in FIG. 3, after the metal films 7, 8, 9 are provided on the semiconductor substrate 1, the adhesive sheet prepared in Reference Example 1 is rolled at 50 ° C. on the metal film. Pasted along. Thereafter, the mixture was heated and held at this temperature for 1 minute and cooled to room temperature. When the adhesive sheet was peeled off, only the metal films 7, 8, and 9 on the insulating film 3 were peeled off together with the adhesive sheet, and a metal electrode pattern for bump connection was formed on the electrode portion 4.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a semiconductor substrate having a convex insulating portion and a concave electrode portion.

FIG. 2 is a cross-sectional view of a method of performing a surface treatment only on a convex insulating portion.

FIG. 3 is a cross-sectional view in which a metal film is provided on the surfaces of a convex insulating portion and a concave electrode portion.

FIG. 4 is a step of attaching a metal film peeling and removing adhesive sheet to the metal film of FIG. 3;

FIG. 5 is a metal electrode pattern formed on a concave electrode portion on a semiconductor substrate.

[Explanation of symbols]

 Reference Signs List 1 semiconductor substrate 3 insulating part 4 electrode part 5 sheet for surface treatment 7, 8, 9 metal film A adhesive sheet

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ryo Namagawa 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Chikage Noritake 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Inside Denso Co., Ltd. (72) Inventor Ichiharu Kondo 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. Inside the Denso Co., Ltd. (72) Inventor Ken Miyajima 1-1-1, Showa-cho, Kariya-shi, Aichi Pref.

Claims (6)

[Claims] 1. A flat or sheet-like article (B) only on the surface of a convex portion on a substrate (A) having an uneven surface.
A method for treating a surface of a substrate, characterized by selectively changing properties of a surface portion of a convex portion on a substrate (A) by contacting the surface portion of the substrate. 2. A part of a surface member of the article (B) is transferred to a surface of a projection on the substrate (A) by bringing the surface of the article (B) into contact with the article. The method for treating a surface of a substrate according to claim 1. 3. The method according to claim 2, wherein the surface member of the article (B) contains a fluorine-containing resin. 4. The method for treating a surface of a substrate according to claim 2, wherein the surface member of the article (B) contains a fluorine adhesive substance. 5. A substrate (A) having an uneven shape on its surface,
The method according to any one of claims 1 to 4, wherein the semiconductor substrate has a convex insulating portion and a concave electrode portion formed on a surface thereof. 6. A step of performing a surface treatment method according to claim 5 on a semiconductor substrate having a convex insulating portion and a concave electrode portion formed on a surface thereof, and thereafter forming a metal film on the entire surface of the substrate.
After attaching the adhesive sheet to the entire surface of the outermost layer portion of the formed metal film, by performing a step of peeling the adhesive sheet, the metal film on the surface of the convex insulating portion is selectively peeled and removed. Forming a metal film pattern only on a concave electrode portion on a semiconductor substrate.