JP3326779B2 - Semiconductor device manufacturing method and 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 manufacturing a semiconductor device for forming bumps on a semiconductor device, and to a method of manufacturing the same.
The present invention relates to a semiconductor device to be used.

[0002]

2. Description of the Related Art Some semiconductor device mounting methods include (1)
A semiconductor chip is mounted on a circuit board via bumps formed on the semiconductor chip, so-called flip-chip mounting, and (2) bumps formed on the semiconductor chip and leads formed on a carrier tape. Of one end and the other end of the lead is mounted on the circuit board.
There is a so-called tape bonding (abbreviation "TAB") mounting and the like, and any mounting requires a bump.

FIG. 3 is a side sectional view showing an example of a bump forming method in a conventional semiconductor device. In the figure, reference numeral 41 denotes a semiconductor wafer, 42 denotes an Al (aluminum) electrode pad,
Reference numeral 3 denotes a passivation film for protecting the surface. Therefore,
Next, a bump forming method in a conventional semiconductor device will be described with reference to FIG.

First, as shown in FIG. 3A, a semiconductor wafer 41 having an Al electrode pad 42 and a passivation film 43 provided on a semiconductor wafer 41 is prepared.

Next, as shown in FIG. 3B, Cr (chromium) and Cu (copper) are deposited on the semiconductor wafer 41 from the Al electrode pad 42 side to a thickness of 0.3 μm and a thickness of 0.8 μm, respectively. Then, a barrier metal 44 is formed.

Next, as shown in FIG. 3C, the photosensitive liquid resist 45 is covered with the barrier metal 44 and has a thickness corresponding to the height of the bump, that is, a thickness slightly larger than the height of the bump (generally, approximately (25-30 μm).

In this case, since the photosensitive liquid resist 45 contains a solvent in the spin coating of the photosensitive liquid resist 45, heating is performed after the spin coating is performed, and the spin coating of FIG. As shown in ()), the solvent is gasified to release gas 46 from all surfaces of the resist surface.

Next, as shown in FIG. 3E, the photosensitive liquid resist 45 is exposed to light 48 using a predetermined mask 47.

After that, it is developed. Then, a bump forming pattern 49 is formed as shown in FIG.

Next, a solder plating process is performed to form a bump 50 on the bump forming pattern 49 as shown in FIG.

Next, as shown in FIG. 3H, the photosensitive liquid resist 45 is removed, and unnecessary portions of the barrier metal 44 are also etched as shown in FIG. finish.

In the conventional method for forming a bump in a semiconductor device, a photosensitive liquid resist 45 having a large thickness is used.
When spin-coating is performed, a resist pool called a crown 45a may be generated around the semiconductor wafer 41 as shown in FIG. Then, when the crown 45a occurs, the film thickness on the same semiconductor wafer 41 is different between the central portion and the peripheral portion of the semiconductor wafer 41, such that the peripheral portion has a larger film thickness than the central portion. Therefore, it is ideally necessary to change the exposure amount for each portion having a different thickness. However, it is difficult for the exposure apparatus that performs the exposure to partially change the exposure amount according to the resist thickness in the same semiconductor wafer 41. Therefore, generally, the entire exposure amount is adjusted so that the central portion of the semiconductor wafer 41 becomes the optimal exposure.

[0013]

As described above, according to the bump forming method in the conventional semiconductor manufacturing apparatus, when the photosensitive liquid resist 45 having a large thickness is spin-coated, the crown 45a is formed around the periphery of the semiconductor wafer 41. A so-called resist pool sometimes occurred. Therefore, it is necessary to partially change the exposure amount according to the resist thickness in the semiconductor wafer 41. However, since it is difficult to change the exposure amount partially with the current technology, the occurrence of uneven exposure is avoided. I couldn't.

Therefore, when the semiconductor wafer 41 is not completely formed with a pattern and the photosensitive liquid resist 45 is not developed on the Al electrode pad 42, as shown in FIG. Some may remain as resist residue 51. If the resist residue 51 remains, this portion is not plated in the subsequent bump plating step, so that there is a problem that the bump 50 cannot be formed only in this portion. FIG. 6 shows the photosensitive liquid resist 4 on the Al electrode pad 42.
5 shows the case where the film was completely developed. In this case, Al
The barrier metal 44 on the electrode pad 42 is exposed, and the bump 5 is formed on the exposed barrier metal 44.
0 is formed.

On the other hand, in the bump forming method, in order to avoid the problem of crown, a photosensitive dry film resist (hereinafter referred to as "DFR") having a predetermined thickness uniformly without using a photosensitive liquid resist. Is also used by directly laminating it on a barrier metal serving as a base material. However, due to unevenness (rough surface) existing on the surface of the semiconductor wafer 41, a photosensitive dry film resist Inadequate adhesion over the entire surface.

Therefore, when the bump 50 is formed on a semiconductor device having a fine electrode pad pitch by using a photosensitive dry film resist, a plating solution is applied between the photosensitive dry film resist and the barrier metal 44 at the time of bump plating. There is a problem that an adjacent bump is short-circuited below the bump, for example.

In the flip-chip mounting described above, it is said that the height of the bumps 50 may be increased to further improve the reliability of the semiconductor device. For this purpose, a thicker resist (15 μm or more) is used. Must be applied with a uniform thickness over the entire surface of the semiconductor wafer 41. However, this was not possible with the technique of applying only a photosensitive liquid resist as in the prior art.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a method of manufacturing a semiconductor device capable of forming a good bump over the entire semiconductor device.
And a semiconductor device obtained thereby .

[0019]

In order to solve the problem] was to achieve the above purpose
In the method of manufacturing a semiconductor device according to the present invention,
A method of forming bumps on a semiconductor device, in which the step of applying a photosensitive liquid resist on the base material, and be provided a step of laminating a photosensitive dry film resist on the photosensitive liquid resist is there.

Preferably, the photosensitive dry film resist is laminated while heating and pressurizing it in a temporarily dried state in which the photosensitive liquid resist has fluidity.

Further, preferably, holes are formed in the photosensitive dry resist before lamination.

[0022]

The manufacturing method and the semiconductor manufactured by the method
According to the apparatus , when the photosensitive liquid resist is applied, the unevenness existing on the surface of the semiconductor wafer is absorbed, and when the photosensitive dry film resist is further laminated on the photosensitive liquid resist, the photosensitive dry film resist is used. Since the photosensitive liquid resist is pressed and flattened, even if a crown is generated in the photosensitive liquid resist, the crown is also flattened at the same time, and eventually the total thickness of the resist becomes uniform over the entire semiconductor wafer. Will be retained.

Further, due to the use overlapping a photosensitive liquid resist and a photosensitive dry film resist double it is possible to increase the total thickness of the resist, is obtained particularly suitable for flip-chip mounting.

Further, if a hole penetrating vertically is provided before laminating to the photosensitive dry film resist, the hole serves as a hole for degassing for drying the solvent of the photosensitive liquid resist after lamination. The photosensitive liquid resist can be completely dried even under the photosensitive dry film resist. If a large crown is present in the photosensitive liquid resist, the excess photosensitive liquid resist flows into these holes and escapes, and the total thickness becomes more uniform over the entire semiconductor wafer.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a process chart showing one embodiment of a method for forming a bump on a semiconductor device according to the present invention, that is, a method for manufacturing a semiconductor device .

In FIG. 1, a semiconductor wafer 1 on which bumps are formed is a semiconductor wafer formed by forming a circuit on a Si (silicon) wafer, and an electrical test as a semiconductor device has already been performed. In the figure, reference numeral 2 denotes an Al electrode pad, and reference numeral 3 denotes a passivation film for surface protection. Therefore, a method for forming a bump on a semiconductor device will be described below with reference to FIG.

First, as shown in FIG. 1A, an Al electrode pad 2 and a passivation film 3 are formed on a semiconductor wafer 1.
Is provided.

Next, as shown in FIG. 1B, Cr (chromium) is applied to the semiconductor wafer 1 from the Al electrode pad 2 side.
0.3 μm, Cu (copper) is deposited at a thickness of 0.8 μm, respectively.
A barrier metal 4 is formed as a base material.

Next, as shown in FIG. 1C, a photosensitive liquid resist 5 is spin-coated so as to cover the barrier metal 4 with a thickness (normally about 25 to 30 μm) corresponding to the bump height. As a result, the semiconductor wafer 1 and the photosensitive liquid resist 5 have high adhesion over the entire surface of the semiconductor wafer 1.

In this case, since the photosensitive liquid resist 5 contains a solvent, the photosensitive liquid resist 5 is continuously heated after the spin coating is performed, so that the solvent is removed. Preliminary drying is performed until 90% is gasified, and gas 6 is released from all surfaces of the resist surface as shown in FIG. At this time, the photosensitive liquid resist 5 still has fluidity to the extent that the crown is flattened by pressurization.

Next, as shown in FIG. 1E, a photosensitive dry film resist having a uniform thickness of about 50 μm is placed on the temporarily dried photosensitive liquid resist 5 which still has fluidity. 7 are stacked and laminated while heating and pressing so that the surface of the photosensitive liquid resist 5 becomes even and flat. Here, the photosensitive dry film resist 7 used is one in which holes 8 vertically penetrated in advance by a process such as a punch (not shown) are formed.

FIG. 2 is a sectional side view showing a state after the photosensitive dry film resist 7 is laminated on the photosensitive liquid resist 5 in this step. Therefore,
The operation of laminating the photosensitive dry film resist 7 on the photosensitive liquid resist 5 will be further described with reference to FIG. 2. By the step before the photosensitive dry film resist 7 is laminated on the photosensitive liquid resist 5, When the crown generated in the peripheral portion of the semiconductor wafer 1 is heated and pressurized in this step, it is pushed into the hole 8 together with the excess photosensitive liquid resist 5, and the total thickness of the photosensitive liquid resist 5 is eventually reduced to the semiconductor thickness. It becomes uniform at the center and the periphery of the wafer 1.

Thereafter, as shown in FIG. 1F, the photosensitive liquid resist 5 is completely dried by heating. Then, at this time, the gas from the photosensitive liquid resist 5 under the photosensitive dry film resist 7 is released to the outside through the hole 8,
It can be completely dried.

When the double resist is formed as described above, light 1 is applied using a predetermined mask 10 as shown in FIG.
Exposure by 1. At this time, the two types of resists, the photosensitive liquid resist 5 and the photosensitive dry film resist 7, can be exposed at once.

Further, development is performed to form a bump forming pattern 12 on the Al electrode pad 2 as shown in FIG.

Thereafter, as shown in FIG. 1I, solder plating is performed until the height of the bump 13 reaches 70 μm, and the bump 13 is grown.

Next, the removal of the photosensitive liquid resist 5 and the photosensitive dry film resist 7 is performed like lift-off using a stripper of the photosensitive liquid resist 5 as shown in FIG. 1 (j). The removal of the resist may be performed in separate steps, for example, after the photosensitive dry film resist 7 is removed, and then the photosensitive liquid resist 5 is removed.

Further, finally when etching the barrier metal 4 in the etching solution, the formation of the bump 13 as shown in (k) of FIG. 1 is completed, the semiconductor wafer with bumps 13
-1, that is, the intended semiconductor device is obtained.

[0039]

As described above, according to the present invention,
The application of the photosensitive liquid resist absorbs the unevenness present on the surface of the semiconductor wafer, and furthermore, when the photosensitive dry film resist is laminated on the photosensitive liquid resist, the photosensitive liquid resist is applied by the photosensitive dry film resist. Since the resist is pressed and flattened, even if a crown is generated in the photosensitive liquid resist, the crown is also flattened at the same time, so that the total thickness of the resist is uniformly maintained over the entire surface of the semiconductor wafer. As a result, it is possible to form a complete pattern without resist residue at the electrode portion of the semiconductor device even at the peripheral portion of the semiconductor wafer, thereby eliminating the fact that bump plating cannot be performed,
A bump can be formed over the entire semiconductor device.

Further, due to the use overlapping a photosensitive liquid resist and a photosensitive dry film resist double it is possible to increase the total thickness of the resist, is obtained particularly suitable for flip-chip mounting.

Further, if a hole penetrating vertically is provided before lamination to the photosensitive dry film resist, the hole serves as a hole for degassing for drying the solvent of the photosensitive liquid resist after lamination. Since the photosensitive liquid resist can be used, drying of the photosensitive liquid resist can be completely performed even under the photosensitive dry film resist. If a large crown exists in the photosensitive liquid resist, an excess of the photosensitive liquid resist flows into the holes and escapes, and an effect such that the total thickness becomes more uniform over the entire semiconductor wafer can be expected.

[Brief description of the drawings]

FIG. 1 shows a bump forming method according to the present invention, that is, a semiconductor device.
FIG. 7 is a schematic side sectional view for illustrating the method for manufacturing the semiconductor device.

FIG. 2 is a schematic side sectional view for explaining in detail a main process step part of the present invention.

FIG. 3 is a schematic sectional side view for explaining a conventional bump forming method.

FIG. 4 is a schematic side sectional view for describing in detail a conventional main process step portion.

FIG. 5 is a schematic side sectional view showing a portion that has become an undeveloped portion in the conventional method.

FIG. 6 is a schematic side sectional view showing a portion which has become a complete developing section in a conventional method.

[Explanation of symbols]

1 semiconductor wafer 2 Al electrode pads 3 passivation film 4 barrier metal (base material) 5 photosensitive liquid resist 6 gas 7 photosensitive dry film resist (DFR) 8 holes 9 gas 10 mask 11 light 12 bump forming pattern 13 bumps

Claims (4)

(57) [Claims] 1. A method of forming a bump on a semiconductor device, comprising: a step of applying a photosensitive liquid resist on a base material; and a step of laminating a photosensitive dry film resist on the photosensitive liquid resist. A method for manufacturing a semiconductor device , comprising: 2. The method of manufacturing a semiconductor device according to claim 1, wherein the photosensitive dry film resist is laminated while heating and pressing in a temporarily dried state in which the photosensitive liquid resist has fluidity. . Wherein wherein the photosensitive dry resist, a method of manufacturing a semiconductor device according to claim 1 which is adapted in advance to form a hole prior to lamination. 4. The method of manufacturing a semiconductor device according to claim 1,
The manufactured semiconductor device.