JP2993697B2 - Method for manufacturing semiconductor device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device and a method for processing an object to be processed, and particularly to a method for baking an insulating film applied to a semiconductor wafer (hereinafter simply referred to as a wafer). Heat treatment technology.

[Conventional technology]

In order to stabilize the quality of a photoresist or a surface protective film applied to a wafer, for example, an insulating film such as polyimide, a heat treatment technique of placing the wafer on a hot plate and baking the insulating film is disclosed in, for example, It is described in JP-A-61-281527.

The hot plate in the above-described conventional heat treatment apparatus is provided with a planar heating element for making the surface temperature uniform, and the heating surface of the hot plate is designed to be larger than the diameter of the wafer.

In order to bake polyimide applied on a wafer, for example, using such a heat treatment apparatus, first, polyimide is spin-coated on the wafer by spinner coating or the like, and then the wafer is placed on a hot plate. Then, a heat treatment is performed in a state where the heat treatment is performed by vacuum suction. By the way, since the polyimide is spin-coated, it is applied to the entire surface of the main surface of the wafer, but the polyimide on the outer periphery of the wafer is peeled off and contaminated when the wafer is fixed with the clamp claws, or rises to form a back surface. The problem that the wafer is easily cracked at the time of grinding or the swelling of the wafer causes the probe pin to be in contact with and adhere to the probe pin at the time of the probe inspection to easily cause an erroneous inspection occurs. Therefore, conventionally, after baking the polyimide on the wafer with a heat treatment apparatus, it was necessary to add a photolithography step for removing the polyimide on the outer periphery of the wafer separately from the photolithography step for forming an integrated circuit. .

[Problems to be solved by the invention]

However, the present inventor has found that the above-described conventional technology has the following problems.

That is, for example, when a bordering process for removing an undried insulating film from the outer periphery of the wafer to the back surface side cannot be performed depending on the insulating film applied on the wafer, such as a surface protective film of polyimide or the like. However, when a wafer in such a state is placed on a hot plate of a heat treatment apparatus, the heated surface of the hot plate is larger than the diameter of the wafer, and the undried insulating film that has wrapped around the back surface of the wafer is removed. There is a problem that the contaminant adheres to the heating surface of the hot plate, and the adhered and solidified insulating film causes a transport error when transporting the wafer.

Also, a photolithography process for removing the insulating film on the outer periphery of the wafer is required after the application of the insulating film, separately from the photolithography process for forming the integrated circuit during the manufacturing process of the semiconductor integrated circuit device, The processing steps such as mask production, exposure, and development for that purpose have caused a problem that the number of manufacturing steps and manufacturing cost of the semiconductor integrated circuit device increase.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of improving the reliability and yield of a semiconductor integrated circuit device.

Another object of the present invention is to provide a technique capable of reducing the number of manufacturing steps and manufacturing cost of a semiconductor integrated circuit device.

The above and other objects and novel features of the present invention are as follows.
It will be apparent from the description of the specification and the accompanying drawings.

[Means for solving the problem]

The outline of a representative invention among the inventions disclosed in the present application will be briefly described as follows.

That is, the invention according to claim 1 is a step of spin-coating a material of an insulating film on the entire surface of the semiconductor wafer, wherein the insulating film in an outer peripheral region of the semiconductor wafer and the insulating film in an inner region of the semiconductor wafer are exposed to an etchant. Forming an insulating film so as to have a selectivity with respect to the semiconductor wafer, etching the insulating film in the outer peripheral region of the semiconductor wafer,
Is a method for manufacturing a semiconductor device having:

According to a third aspect of the present invention, there is provided a method of forming a coating film by spin-coating a material of a coating film on a surface of a processing object, and applying the coating film in an inner region of the processing object to a back surface of the processing object. Using a hot plate that does not have a heating surface that has a heating surface to heat from the back side of the object to be processed, and has a heating surface that heats the coating film in the outer peripheral region of the object to be processed. Heating the coating film so as to cause a difference in quality between the coating film in the inner region and the coating film in the outer peripheral region of the processing object, and removing the coating film in the outer region of the processing object And a step of processing the object to be processed.

[Action]

According to the invention described above, the insulating film in the outer peripheral region of the wafer is formed so as to have a difference in film quality from the insulating film in the inner region of the wafer. For example, a developing process for forming an integrated circuit after the heat treatment or an etching process It is easily removed in the process.

According to the invention described in claim 5, it is possible to cause a difference in film quality between the insulating film in the outer peripheral region of the wafer and the insulating film in the inner region of the wafer. Can be prevented from adhering to the hot plate.

Embodiment 1 FIG. 1 is a plan view showing a hot plate and a wafer in a heat treatment apparatus used in a manufacturing method according to an embodiment of the present invention. FIG. 2 is a side view of the hot plate and the wafer. FIG. 3 is a partial cross-sectional view showing a cross section of the hot plate and the outer peripheral portion of the wafer shown in FIGS. 1 and 2, and FIGS. 4 (a) and 4 (b) are cross-sectional views of a main part of the wafer for explaining a heat treatment method. FIG. 5 is a cross-sectional view of a main part of the wafer for explaining the steps after the heat treatment.

The heat treatment apparatus 1 used in the manufacturing method of the first embodiment shown in FIGS. 1, 2 and 3 has a hot plate 4 for baking the insulating film 3 applied on the wafer 2.

The hot plate 4 is made of metal, ceramic, or the like. Inside the hot plate 4, a heating source such as a heater and a temperature detector such as a thermocouple are provided (not shown).

The shape of the heating surface 4 a of the hot plate 4 is, for example, a circular shape. In the first embodiment, the diameter of the heating surface 4 a is smaller than the diameter of the wafer 2. Therefore, in the heat treatment apparatus 1 used in the manufacturing method of the first embodiment, as shown in FIG.
The hot plate 4 does not come into contact with the back surface of the outer peripheral region A of the wafer 2 when placed on the upper surface. That is, for example, even when the insulating film 3 applied to the wafer 2 cannot be trimmed like polyimide, the insulating film 3a which has wrapped around from the outer periphery of the wafer 2 to the rear surface side is hot plate 4
Does not adhere to

In the heat treatment apparatus used in the first embodiment, the diameter of the heating surface 4a is set so as to include the chip formation region group 5 formed on the wafer 2. Therefore, the heating surface 4a of the hot plate 4 is in contact with the back surface of the chip formation region group 5 of the wafer 2.
That is, after the heat treatment, the heat treatment apparatus 1 used in the first embodiment
And the film quality of the insulating film 3 in the inner region B of the wafer 2 can be made different.

The heat processing apparatus 1 is provided with a positioning mechanism (not shown) for accurately placing the wafer 2 on the hot plate 4. Also, the hot plate 4
Vacuum suction hole (not shown) for vacuum suction of wafer 2
Is provided.

Next, the heat treatment method used in the first embodiment will be described with reference to FIGS. 4 (a), (b) and FIG. In the first embodiment, for example, the insulating film 3 will be described as polyimide.

First, as shown in FIG. 4 (a), polyimide is spin-coated on the wafer 2 by a spinner coating method or the like to form an undried insulating film 3 having a uniform thickness. In addition, unlike the case of a positive photoresist or the like, the solvent is injected into the peripheral portion of the wafer 2 from the front side or the back side of the wafer 2 after the spin coating, so that the outer periphery of the wafer 2 and the outer periphery are removed from the outer periphery. Cannot be dissolved and removed.

Subsequently, as shown in FIG. 4B, the wafer 2 is placed on the hot plate 4 of the heat treatment apparatus 1 in a state where the wafer 2 is accurately aligned. Then, a pre-bake process is performed while the wafer 2 is vacuum-sucked. At this time, since the heating surface 4a of the hot plate 4 does not contact the back surface of the outer peripheral region A of the wafer 2, the insulating film 3 in the outer peripheral region A of the wafer 2
There is a difference in film quality between the insulating film 3 and the inner region B of the wafer 2. That is, although the solvent is evaporated and dried in the insulating film 3 in the outer peripheral region A of the wafer 2, the film quality is unstable compared with the film quality of the insulating film 3 in the inner region B of the wafer 2. .

Next, after passing through a photolithography process in the chip formation region group 5 (see FIG. 1) of the wafer 2, an etching process is performed. At this time, the wafer 2 whose film quality is unstable
As shown in FIG. 5, the insulating film 3 in the outer peripheral region A is removed by etching without adding a photolithography step to the outer peripheral region A of the wafer 2. That is, in the first embodiment, a photolithography step for removing the insulating film 3 in the outer peripheral region A of the wafer 2 is not required.

As described above, according to the first embodiment, the following effects can be obtained.

(1). By making the diameter of the heating surface 4 a of the hot plate 4 smaller than the diameter of the wafer 2, it is possible to prevent the insulating film 3 a wrapping around from the outer periphery of the wafer 2 to the back surface from adhering to the hot plate 4. Becomes possible.

(2). According to the above (1), it is possible to prevent the generation of contaminants due to the insulating film 3a wrapping around the back surface of the wafer 2 and to prevent the transfer error of the wafer 2, thereby improving the reliability and yield of the semiconductor integrated circuit device. It becomes possible.

(3). In pre-baking the insulating film 3 on the wafer 2,
The hot plate 4 and the outer peripheral region A of the wafer 2 are brought into non-contact with each other, and a difference is generated in the film quality of the insulating film 3 between the outer peripheral region A of the wafer 2 and the inner region B of the wafer 2. Since the quality of the insulating film 3 in the region A is more unstable than that of the insulating film 3 in the inner region B of the wafer, for example, a developing process or an etching process for forming an integrated circuit after the heat treatment is performed. In the process, it becomes possible to remove the resist at the same time.

(4). According to the above (3), the photolithography step for removing the insulating film 3 in the outer peripheral region A of the wafer 2 becomes unnecessary, and the number of manufacturing steps and manufacturing cost of the semiconductor integrated circuit device can be reduced.

Embodiment 2 FIG. 6 is a plan view showing a hot plate and a wafer in a heat treatment apparatus according to another embodiment of the present invention, and FIG. 7 is a side view of the hot plate and the wafer shown in FIG. FIG. 8 is a partial cross-sectional view showing a cross section of the hot plate, the cooling means, and the outer peripheral portion of the wafer shown in FIGS. 6 and 7.

In the heat treatment apparatus 1 according to the second embodiment shown in FIGS. 6, 7 and 8, the diameter of the heating surface 4a of the hot plate 4 is smaller than the diameter of the wafer 2, and A water cooling pipe (cooling means) 6 is provided on the outer periphery of the surface 4a. The water cooling pipe 6 is connected to a constant temperature water circulator (not shown).

That is, in the heat treatment apparatus 1 according to the second embodiment,
When the insulating film 3 applied to the wafer 2 is baked, the insulating film 3 in the outer peripheral area A of the wafer 2 can be forcibly cooled. Therefore, the structure is such that the difference between the film quality of the insulating film 3 in the outer peripheral region A of the wafer 2 and the film quality of the insulating film 3 in the inner region B of the wafer 2 can be made larger than in the case of the first embodiment. ing.

As described above, according to the heat treatment apparatus 1 of the second embodiment, since the cooling pipe 6 is provided on the outer periphery of the heating surface 4a of the hot plate 4, the film quality of the insulating film 3 in the outer peripheral area A of the wafer 2 2, the difference between the film quality of the insulating film 3 in the inner region B, that is, the difference in the development resistance and the etching resistance can be made larger than that in the first embodiment. The film 3 can be removed more easily than in the first embodiment.

As described above, the invention made by the inventor has been specifically described based on the embodiments. However, the present invention is not limited to the first and second embodiments, and can be variously modified without departing from the gist thereof. Needless to say.

For example, in the first and second embodiments, the case where the shape of the heating surface of the hot plate is circular is described. However, the present invention is not limited to this, and various modifications can be made. For example, the hot plate shown in FIG. Like the heating surface 4b of 4,
It may have the same shape as the chip formation region group 5 formed on the wafer 2. Also in this case, a cooling means may be provided on the outer periphery of the heating surface 4b.

In the second embodiment, the case where the cooling means is provided on the outer periphery of the heating surface of the hot plate is described. However, the present invention is not limited to this, and various modifications can be made. A member made of a material having a lower thermal conductivity than the material of the portion may be provided.

〔The invention's effect〕

The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.

(1). That is, in the insulating film applied to the wafer, the insulating film in the outer peripheral region of the wafer has an unstable film quality as compared with the insulating film in the inner region of the wafer. It is possible to remove the resist simultaneously with the resist in the developing step and the etching step for the above. As a result, a photolithography step for removing the insulating film on the outer periphery of the wafer becomes unnecessary, and the number of manufacturing steps and manufacturing cost of the semiconductor integrated circuit device can be reduced.

(2). In the step of heating the insulating film applied to the wafer, a hot plate having a heating surface for heating the inner region of the wafer from the back surface of the wafer and having no heating surface for heating the outer peripheral region of the wafer from the back surface of the wafer is used. According to the configuration for processing, the following effect can be obtained in addition to the effect (1). That is, the contact state between the back surface of the wafer outer periphery and the hot plate can be set to a non-contact state,
It is possible to prevent the insulating film that has spread from the outer periphery of the wafer to the back side from adhering to the hot plate. As a result, it is possible to prevent the generation of contaminants due to the insulating film wrapping around the back surface side of the wafer and to prevent the transfer error of the wafer, thereby improving the reliability and yield of the semiconductor integrated circuit device. .

[Brief description of the drawings]

FIG. 1 is a plan view showing a hot plate and a wafer in a heat treatment apparatus used in the manufacturing method according to one embodiment of the present invention, FIG. 2 is a side view of the hot plate and the wafer, and FIG. FIGS. 4A and 4B are partial cross-sectional views showing cross sections of the hot plate and the outer peripheral portion of the wafer shown in FIG. 2 and FIG. FIG. 6 is a cross-sectional view of a main part of a wafer explaining a process after a heat treatment. FIG. 6 is a plan view showing a hot plate and a wafer in a heat treatment apparatus used in a manufacturing method according to another embodiment of the present invention. Is a side view of the hot plate and the wafer shown in FIG. 6, FIG. 8 is a hot plate shown in FIG. 6 and FIG.
FIG. 9 is a partial cross-sectional view showing a cross section of a cooling means and an outer peripheral portion of a wafer. FIG. 9 is a plan view showing a heating surface of a hot plate and a wafer in a heat treatment apparatus according to another embodiment of the present invention. 1 ... heat treatment device, 2 ... wafer, 3, 3a ... insulating film,
4 hot plate, 4a, 4b heating surface, 5 chip formation region group, 6 cooling tube, A outer peripheral region, B
Inner area.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Kurihara 3-3-2 Fujibashi, Ome-shi, Tokyo Within Hitachi Tokyo Electronics Co., Ltd. (72) Inventor Shinkichi Hirota 3-2-2 Fujibashi, Ome-shi, Tokyo Hitachi Tokyo Electronics Inside (72) Inventor Osamu Yamamoto 3-3-2 Fujibashi, Ome-shi, Tokyo Within Hitachi Tokyo Electronics Co., Ltd. (72) Inventor Rokuro Watanabe 3300 Hayano, Mobara-shi, Chiba Pref. References JP-A-60-24037 (JP, A) JP-A-58-91637 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/312 H01L 21/027

Claims (3)

(57) [Claims] A step of spin-coating an insulating film material over the entire surface of the semiconductor wafer, wherein the insulating film in an outer peripheral region of the semiconductor wafer and the insulating film in an inner region of the semiconductor wafer have a selectivity to an etching solution. A method of manufacturing a semiconductor device, comprising: a step of forming an insulating film so as to have an end; and a step of etching an insulating film in an outer peripheral region of the semiconductor wafer. 2. A step of spin-coating a material of an insulating film on a first region and a second region surrounding the first region of the semiconductor wafer, the insulating film in the first region and the second region Baking by changing the degree of heating of the first region and the second region so as to cause a difference in the film quality of the insulating film, and removing the insulating film in the second region. Device manufacturing method. 3. A step of forming a coating film by spin-coating a material of a coating film on a surface of the processing object, wherein the coating film in an inner region of the processing object is heated from the back surface of the processing object. Using a hot plate having a heating surface and not having a heating surface to heat the coating film in the outer peripheral region of the object to be processed from the back surface of the object to be processed, the inner region of the object to be processed is A step of heating the coating film so as to cause a difference in film quality between the coating film and the coating film in an outer peripheral region of the object to be processed; and a step of removing the coating film in an outer peripheral region of the object to be processed. Processing method of the workpiece.