JPS6054782B2 - Manufacturing method of semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a semiconductor device having metal bumps.

Conventionally, the following manufacturing method is known as such a product.

That is, an insulating film 2 made of SiO2 or the like is provided on a semiconductor substrate 1 made of silicon or the like, and electrode pads 3 made of an aluminum film are provided on this film for connecting between elements and leading to the outside.
will be established. Electrode pad 3 excluding a part of the upper surface of electrode pad 3
and CVDSi0 on the surface of the semiconductor substrate 1. Deposited with film 4. Next, a part of the upper surface of the electrode pad 3 and the CV
DSi0. A two-layer metal film 5 made of, for example, Cr and Cu is deposited on the film 4 by vacuum evaporation, and the two-layer film 5 is removed from other parts, leaving the electrode pad "3". A pattern 11 of photosensitive resin or the like is formed on the metal film 5 (FIG. 1a). Next, a part or one layer of the metal film is removed (FIG. 1b). Next, the photosensitive resin pattern 11 is removed. , a plating mark 12 is formed of a photosensitive resin. Then, a part 5' of the metal film 5 is used as a common electrode for plating, and a bump 8 is formed by electrodeposition (FIG. 1c). The resin 12 is removed, and a part 5' of the metal film 5 is removed using the metal film 5 as a mask (FIG. 1d).However, in this method, when removing the part 5'' of the metal film 5, At the same time, other parts of the metal film 5 are also removed.

Therefore, since it is necessary to deposit the other portions of the metal film 5 thicker than necessary, extra vapor deposition material and vapor deposition time are required. Furthermore, when removing the metal film 5'', the removal liquid for the metal film 5'' seeps into the boundary between the bump 8 and the metal film 5, corrodes the electrode pad 3, and reduces the adhesion strength of the bump 8 and the bump 8. The contact resistance between the electrode pads 3 also increases,
This caused electrical failure and significantly reduced reliability. Furthermore, since the etching process requires two steps, shown in FIG. 1b and FIG. 1d, the process becomes complicated and the time required for the process also increases. The present invention has been made to eliminate such conventional drawbacks, and one embodiment thereof will be described below with reference to the drawings.

[Example (1)] A SiO film 22 is formed on a semiconductor substrate 21 made of silicon or the like, and an electrode pad 23 made of an aluminum film with a thickness of about 0.5 to 2.0 pm is formed thereon.

CVDSiO2 for further mechanical or electrical protection
A film 24 is formed on the semiconductor substrate 21, and an opening 25 is formed in a portion of the electrode 23 using a photoetching agent method. That is,
A photosensitive resin is applied onto the CVDSiO2 film 24 to form a pattern in which only the electrode portions are opened. In this state, if immersed in a solution of hydrofluoric acid and ammonium fluoride at a ratio of, for example, 1:10, the CVDSlO2 film at the opening will be 1500 to 25
It is removed at a speed of 00A/min, resulting in the state shown in FIG. 2a. Next, a metal film 26 consisting of multiple layers is formed over the entire surface by a vapor deposition method.

The metal film 26 is made of Cr-Cu, Ni-Cu, Cr-Ni.
-Cu or Cr-Cu-Au, Ni-Cu-Au,
Consisting of multiple layers such as Cr-Ni-Cu, etc. There are methods in which deposition is performed sequentially while maintaining a vacuum state during one deposition.
That is, when a predetermined degree of vacuum is reached, for example, a heater for Cr is heated, the shutter is opened, and when a certain time has elapsed, the shutter is closed, and the current of the heater for Cr is also lowered.
Next, by heating the Cu heater and opening and closing the shutter for a certain period of time, a Cr--Cu two-layer film can be obtained within the same degree of vacuum. Here, Cr or Ni is a film for increasing adhesion with the aluminum electrode portion 23 or CVDSiO2 film 24, Cu is a film for facilitating the formation of bumps by plating, and Cr is ~1500A,. CU has a film thickness of 1000 to 5000A. Further, a Ti film may be used instead of Cr or Ni (FIG. 2b). Next, after coating the entire surface with photosensitive resin 27, the electrode 23 portion is opened as shown in FIG.
A ring-shaped pattern is formed near the electrode 23, and another photosensitive resin 28'' is provided on the photosensitive resin 27 and the metal film 26.

Here, for example, if the photosensitive resin 27 is a negative photosensitive resin that becomes insoluble in a solvent when exposed to light, the photosensitive resin 27
8 is a positive photosensitive resin that becomes soluble in a solvent when irradiated with light. Here, the photosensitive resin 28 is the photosensitive resin 2
Although the pattern may be smaller or larger than the pattern 7, it is preferable that the second photosensitive resin 2
It is preferable that the maximum dimension be the same as or smaller than the maximum dimension of pattern 7.
Further, after forming the developed pattern, the second photosensitive resin 27 is heat-treated at a temperature that causes thermal polymerization in order to increase the adhesive strength with the metal film 26, but the third photosensitive resin 28 After the development pattern is formed, processing is performed at a temperature that does not cause thermal fogging (about 90° C. for AZ-1350J). Next, a plurality of layers of metal film 2
6 as a common electrode for plating and, for example, by electrodepositing solder, copper, gold, etc., bumps 29 are formed on the open metal film 26.

This is shown in Figure 2e. When the bump surface is irradiated with ultraviolet rays, the photosensitive resin 28 is photodecomposed and becomes soluble in a solvent. That is, the photosensitive resin 28 is dissolved in a special developer, leaving the photosensitive resin 2' under the bump. However, since the photosensitive resin 27 is of negative type, it does not dissolve in the developer of the photosensitive resin 28. The structure shown in Fig. 2 f can be obtained. If the metal film 26 is immersed in a liquid that dissolves it, the bumps 2
9 and the portions not covered with the photosensitive resin 27 are easily removed.

If the metal film 26 is a multiple film consisting of two layers of Cu-Cr, the Cu film is removed with a 10% ferric chloride solution, and then immersed in hydrochloric acid or a mixed solution of potassium ferricyanide and caustic soda. Cr film can be removed continuously. The most effective method for removing the metal film 26 is to mix solution A (caustic soda water = 1:2) and solution B (potassium ferricyanide water = 1:3) in a ratio of 1:2. Heat to ℃. As a result, Cr is 25A/sec,
Cu is removed at a rate of 30 A/sec. Therefore, two layers of films can be removed successively in the same solution. FIG. 2g shows this state, showing the bump 29 and the photosensitive resin 27.
The metal film 26 is removed, leaving the portion covered with the metal film 26. Next, in order to remove the second and third photosensitive resins, the state shown in FIG. 2h can be obtained by immersing it in a stripping solvent (for example, J-100).

Further, other embodiments will be explained in detail.

[Example (2)] In the step of FIG. 2c, the above Example (1) used a negative photosensitive resin, but in other examples, a positive photosensitive resin was used. I can do it.

That is, after forming a pattern with positive photosensitive resin as shown in FIG. 2c, the temperature at which thermal fogging completely occurs is
For example, if the positive photosensitive resin is M-1350, 1
Heat treatment is performed in the range of 40° C. to 270° C., and a state in which the material becomes insoluble in a solvent is obtained by light irradiation. After that, as the photosensitive resin 25, a positive type like the photosensitive resin is used, pattern formation is performed, and the temperature is set at a temperature that does not cause thermal fogging.
If it is AZ-1350, it should be heat treated at around 9Cf'C. This is shown in Figure 2d. Next, metal bumps are formed as shown in FIG. Since the plastic resin 27 has already generated heat fog, it is not soluble in the developer. The state shown in FIG. 2f can be obtained. The subsequent steps are the same as in the above example. In Example (1), since the photosensitive resin 27 is negative type, it has good adhesion to the metal film 26, and has chemical resistance to the removal solution of the metal film 26, so the photosensitive resin 27 has good adhesion to the metal film 26. There is little influence of over-etching on the pattern. In Example (2), since both of the photosensitive resins 27 and 28 are positive type, less materials such as photosensitive resin developer are used in the process, and it is different from Example (1). Similarly, since the photosensitive resin 28 is of a positive type, the plating process may be performed in a bright place because it becomes soluble in a solvent and is removed by light irradiation in a later process.

In addition, in Example (3), the photosensitive resin 27 was
Similar to 1), since it is a negative type, it has excellent adhesion and chemical resistance, but since the photosensitive resin 28 is a negative type, the plating process must be performed in a dark place, but the photosensitive resin used in the process It has the advantage of requiring less materials such as resin and developer, and requiring less management.

[Example (3)] In the step shown in FIG. 2c, a negative mold is used as the photosensitive resin 27 to form a pattern, and then thermal polymerization is performed at a temperature for thermal polymerization.

Next, pattern formation is performed using the same negative mold as the photosensitive resin 28, and the temperature is set to 90°C, for example, at a temperature that does not cause thermal fogging.
Heat treatment is performed at about ℃. This is shown in Figure 2c. Next, metal bumps are formed as shown in Figure 2e, and once the formation is complete,
The photosensitive resin 28 is removed by immersing it in a developer. Since the photosensitive resin 27 undergoes thermal polymerization, it is not soluble in the developer. Then, the state shown in Fig. 2 f can be obtained. The subsequent steps are the same as in the other examples. As explained above, when forming a metal film of a desired shape on a metal bump, the present invention can prevent etching from corroding unneeded parts of the metal film, and can also reduce the etching process by one step. As a result, unlike the conventional method which includes an etching process between the first photosensitive resin coating process and the second photosensitive resin coating process, the coating process, The development processing steps can be performed continuously.

Therefore, the present invention can eliminate the conventional processing step of cleaning and drying the semiconductor substrate immediately after the first photosensitive resin coating step, and therefore can significantly simplify the process compared to the conventional method. In addition, since the metal film is removed using one of the photosensitive resins as a mask, it is possible to prevent electrical defects caused by making the metal film thicker than necessary or from seeping the etching solution under the metal bumps, thereby increasing the reliability of semiconductor devices. can significantly improve sex.

In addition, as a means for dividing the semiconductor substrate 21, it is possible to accurately divide the semiconductor substrate 21.
In order to divide the diamond powder at a high yield, a method is often used in which a disk coated with diamond powder is rotated and cut while being washed with water. When cutting at such high speeds, cooling water is sprayed to cool the diamond. Nevertheless, as the temperature of the substrate rises, the metal film 26 is oxidized, and a Cu film, for example, becomes sandy, becomes brittle, crumbles, and disperses, and this also acts under the bumps 29. In some cases, the electrode pads 23 are corroded, the adhesive strength is weakened, and the contact resistance is increased.To solve this main problem, the semiconductor substrate 21 is divided into parts as shown in FIG. 2g using the structure of the present invention. Once this is done, since the metal film 26 is covered with the photosensitive resin 27, the metal film 26 can be prevented from being oxidized as described above.

Moreover, if the photosensitive resin 27 is removed after division, the structure shown in FIG. 2h can be obtained.

[Brief explanation of drawings]

FIGS. 1a to 1d are process diagrams of a conventional semiconductor device manufacturing method,
FIGS. 2a to 2h are process diagrams of a method for manufacturing a semiconductor device according to an embodiment of the present invention. 21... Semiconductor substrate, 23... Electrode pad, 26... Metal film, 27, 28...
・Photosensitive resin.

Claims (1)

[Claims] 1. A step of forming a first insulating layer on a semiconductor substrate including an electrode, and opening the first insulating layer at a desired position on the electrode using a first photosensitive resin film. a step of opening a window for taking out the electrode, and then removing the first photosensitive resin film; and a step of depositing a multilayer metal film over the entire area of the semiconductor substrate, including at least the window opening region. a step of applying a second photosensitive resin on the metal film, opening part or all of the electrode and forming the ring-shaped photosensitive resin pattern so as to surround the vicinity of the electrode; A third photosensitive resin is coated on the photosensitive resin pattern No. 2 and the metal film to form an opening near the electrode, and the third photosensitive resin pattern has an opening that substantially matches the opening of the second photosensitive resin pattern. forming a photosensitive resin pattern using the third and second photosensitive resin patterns as masks, forming metal bumps on the metal film in the exposed areas of the electrodes; and forming a third photosensitive resin pattern using a solvent. a step of removing only the photosensitive resin; a step of removing at least the metal film other than the bump region using at least the second photosensitive resin pattern and the bump as a mask; and a step of removing the second photosensitive resin. A method for manufacturing a semiconductor device, comprising: 2. The method for manufacturing a semiconductor device according to claim 1, wherein the second and third photosensitive resins are made of positive photosensitive resins that become soluble in a solvent upon irradiation with light. . 3. The heat treatment after pattern formation on the second photosensitive resin is carried out at a temperature higher than that at which heat fog occurs, and the heat treatment after pattern formation on the third photosensitive resin is carried out at a temperature at which heat fog does not occur. A method for manufacturing a semiconductor device according to claim 1.