JP3358751B2 - Method for planarizing thick film resist and method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of flattening a thick film resist, and is suitably applied to, for example, a method of flattening a thick film resist applied in a bump forming process on a silicon (Si) wafer.

[0002]

2. Description of the Related Art Conventionally, in a process of forming bumps on a silicon wafer, a thick resist is formed to ensure sufficient quality and reliability. That is, as shown in FIG. 7, a barrier metal layer 4 is formed on a silicon (Si) wafer 2 (FIG. 7A) having an aluminum (Al) electrode 3 formed on the surface (FIG. 7B), A thick resist layer 5 is formed on this surface (FIG. 7C).

In this state, a bump forming portion 6 is formed on the resist layer 5 by a photo process.
(D)) By forming a solder on the bump forming portion 6, a bump made of the solder can be formed.

[0004]

However, when bumps are formed by such a method, in the step of forming a thick resist layer 5 on the silicon wafer 2, as shown in FIG. 5 becomes thicker, and a convex portion 5A called a crown is generated.

As a result, the exposure and etching accuracy deteriorates, and as shown in FIG. 7 (D), the accuracy of the bump forming portion 6 deteriorates, so that an error occurs in the diameter of the bump formed on the bump forming portion 6 and the yield decreases. There was a problem that got worse.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is an object of the present invention to make it possible to perform a shape generation process applied to a thick resist layer with higher precision and uniformity.

[0007]

According to the present invention, there is provided a method for planarizing a thick resist applied to a substrate, comprising the steps of: The formed substrate 2 is inserted between the rotating roll 21 and the receiving base 23 set at a predetermined interval,
The surface of the thick resist layer 5 is flattened.

In the present invention, the method for flattening the thick film resist includes the step of inserting the substrate 2 on which the thick film resist layer 5 is formed between the rotating roll 21 and the receiving table 23 disposed in the vacuum chamber 31. To do it.

In the present invention, the method for flattening a thick-film resist is such that a predetermined sheet 41 is placed on the surface of the thick-film resist layer 5, and the substrate 2 on which the thick-film resist layer 5 is formed and the sheet 41 are simultaneously formed. It is inserted between the rotating roll 21 and the receiving stand 23. Further, in the present invention, a step of forming an electrode on the substrate 2 and a step of forming a barrier metal 4 on the electrode
Forming a thick film resist 5 on the barrier metal 4
Forming a bump forming portion 6 by selectively removing the thick film resist 5, and forming a bump 15 in the bump forming portion 6. after the step of forming a resist 5, those
The substrate 2 on which the thick resist layer 5 is formed is set at a predetermined interval.
Between the rotating roll 21 and the cradle 23
Thus, a step of flattening the surface of the thick resist layer 5 is provided.

[0010]

The surface of the thick-film resist layer 5 is flattened by the rotating roll 21, so that a predetermined shape generation process (the generation process of the forming section 6) for the thick-film resist layer 5 is performed with high accuracy and uniformity. be able to.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

In FIG. 1 in which the same reference numerals are given to portions corresponding to FIG. 7, a barrier metal layer 4 is formed on a silicon wafer 2 having an aluminum (Al) electrode 3 formed on its surface (FIG. 1A The barrier metal layer 4 is made of chromium (Cr) foil 11,
A copper (Cu) foil 12 and a gold (Au) foil 13 are sequentially formed using a sputter or the like.

In this state, a thick resist layer 5 for forming bumps is formed on the surface of the barrier metal layer 4 as shown in FIG. At this time, a convex portion 5A called a crown is formed in the peripheral portion of the thick film resist layer 5. This is inserted in the direction of arrow a between the rotating roll 21 and the receiving stand 23 as shown in FIG.

Here, the interval between the rotating roll 21 and the cradle 23 is formed such that the thick resist layer 5 on which the projections 5A are formed can be flattened. Accordingly, the convex portion 5A of the thick-film resist layer 5 passing between the rotary roll 21 and the pedestal 23 is flattened.

The silicon wafer 2 thus obtained
On the other hand, as shown in FIG. 3A, a bump forming portion 6 is formed by a photo process, and further, as shown in FIG. 3B, a solder bump 15 is formed by plating.

Further, as shown in FIG. 4A, the thick film resist layer 5 is removed by a predetermined chemical, and as shown in FIG. 4B, the barrier metal layer 4 is removed by etching. . In this state, a substantially spherical solder bump 15A is formed by heating and melting the solder bump 15 as shown in FIG.

In the above configuration, after forming the barrier metal layer 4 on the surface of the silicon wafer 2 (FIG. 1A),
When the thick-film resist layer 5 is formed on the surface of the barrier metal layer 4, a protrusion 5A is formed around the thick-film resist layer 5. When the surface of the thick film resist layer 5 is flattened by passing the convex portion 5A through the rotating roll 21, the subsequent bump forming portion 6
In the process (FIG. 3 (A)) for forming the pattern, the exposure accuracy is improved, and the bump forming portion 6 can be formed in a target shape with high accuracy. As a result, the shape of the solder bumps 15 formed on the bump forming portion 6 can be made uniform, and the yield can be improved by that much.

In the process of forming the thick resist layer 5 (FIG. 1B), even if the setting conditions of the spin coating are relaxed and the surface is slightly uneven,
1, the bump forming portion 6 having the target shape can be formed, and the bump forming portion 6 can be more easily formed.
The forming part 6 can be formed.

According to the above-described structure, in a state where the thick-film resist layer 5 has been formed, the flattened resist layer 5 is flattened by the rotating roll 21, so that a more accurate and uniform bump can be formed.

In the above embodiment, the case where the silicon wafer 2 on which the thick-film resist layer 5 is formed is passed through the rotating roll 21 in the air has been described. However, the present invention is not limited to this. You may make it pass through the rotating roll 21.

That is, as shown in FIG.
The receiving table 23 is disposed in the vacuum chamber 31, and the silicon wafer 2 on which the thick film resist layer 5 is formed is inserted between the rotating roll 21 and the receiving table 23. At this time, in the step of applying the thick-film resist layer 5, the air bubbles entrained in the thick-film resist layer 5 escape to the outside by the pressing force of the rotating roll 21 and the negative pressure in the vacuum chamber, so that a more uniform gas is obtained. A thick resist layer 5 can be obtained.

In the above-described embodiment, the case where the silicon wafer 2 on which the thick-film resist layer 5 is formed is directly passed through the rotating roll 21 has been described. However, the present invention is not limited to this, and as shown in FIG. A thin resin sheet 41 is placed on the surface of the thick resist layer 5 and
1 and the cradle 23 may be inserted. In this way, a more stable flatness can be obtained on the surface of the thick resist layer 5.

Further, in the above embodiment, the case where the thick resist layer 5 formed on the surface of the silicon wafer 2 is flattened has been described, but the present invention is not limited to this, and the present invention is not limited to this. The method can be widely applied to a case where a thick resist layer is formed and flattened.

[0024]

As described above, according to the present invention, a thick resist layer applied on a substrate is flattened by using a rotating roll to generate a shape applied to the thick resist layer. Processing can be performed with higher precision and uniformity.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a procedure for forming a bump according to the present invention.

FIG. 2 is a schematic diagram for explaining a method of flattening a thick film resist according to the present invention.

FIG. 3 is a cross-sectional view showing a bump forming procedure according to the present invention.

FIG. 4 is a cross-sectional view showing a bump forming procedure according to the present invention.

FIG. 5 is a schematic diagram illustrating a method for planarizing a thick film resist according to another embodiment.

FIG. 6 is a schematic diagram illustrating a method of flattening a thick film resist according to another embodiment.

FIG. 7 is a sectional view showing a conventional example.

[Explanation of symbols]

2 ... silicon wafer, 3 ... aluminum electrode, 4 ... barrier metal layer, 5 ... thick resist layer, 5A ... convex part, 6
... bump forming part, 15 solder bump, 21 rotating roll, 23 pedestal, 31 vacuum chamber, 4
1 ... Resin sheet.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/60

Claims (4)

(57) [Claims] 1. A method for planarizing a thick-film resist applied to a substrate, the method comprising: flattening a thick-film resist on a substrate; A method of flattening a thick-film resist, wherein the method is inserted between cradles to flatten the surface of the thick-film resist layer. 2. The method of flattening a thick-film resist according to claim 1, wherein said substrate on which said thick-film resist layer is formed is inserted between said rotary roll and said receiving table provided in a vacuum chamber. 2. The method according to claim 1, wherein the thick film resist is planarized. 3. The method of flattening a thick-film resist, comprising: placing a predetermined sheet on the surface of the thick-film resist layer; 2. The method for planarizing a thick film resist according to claim 1, wherein said method is inserted between cradles. A step of forming an electrode on the substrate; a step of forming a barrier metal on the electrode; and a step of forming a thick film resist on the barrier metal.
Forming a bump forming portion by selectively removing the thick resist in the method for manufacturing a semiconductor device and a step of forming a bump on the bump formation portion, after the step of forming the thick film resist , The thick cash register
The substrate on which the strike layer is formed is rotated at a predetermined interval.
A method for manufacturing a semiconductor device, comprising a step of flattening the surface of the thick resist layer by inserting between a roll and a receiving table .