JPH0897278A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE: To eliminate the generation of the inclination of the inner wall surfaces of contact holes formed in an insulating laminated part, whereby to prevent a defective wiring from being formed. CONSTITUTION: A method of manufacturing a semiconductor device, which forms an insulating laminated part A by laminating first insulating films 3 and 5 and second insulating films 2 and 4, which consist of a thermally stable material compared with the material forming the films 3 and 5, on a substrate 1 and forms contact holes 16 in this laminated part A, is provided with an etching process for forming grooves 11 continuously or intermittently in the laminated part A along the length direction of the peripheral edge of a chip formed with the laminated part A at the peripheral part of the chip and a process for filling the grooves 11 with an insulating material 15 consisting of a material which is thermally stabler than the material forming the films 3 and 5.

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 having an insulating laminated portion in which two kinds of insulating films having different thermal properties are alternately laminated, and a contact hole is formed in the insulating laminated portion.

[0002]

2. Description of the Related Art Generally, a semiconductor device has an insulating laminated portion formed by laminating plural kinds of interlayer insulating films for the following reasons, and a large number of contact holes are formed in the insulating laminated portion. That is, the insulating laminated portion is formed
Smoothly covers the case where the interlayer insulating film only needs to have an insulating property and the case where each component formed on the substrate has an uneven upper surface side, in other words, a state in which the step coverage is good. This is because the function may be required in some cases, and materials having different materials, and hence different thermal characteristics, are appropriately selected and film-formed according to the required function.

By the way, in order to manufacture a semiconductor device having such an insulating laminated portion conventionally, first, as shown in FIG. 4A, for example, insulation of a wiring portion is performed by a known film forming method on a silicon substrate 1. For this purpose, a second insulating layer 2 made of SiO ₂ is formed, and then a first insulating film 3 made of, for example, boron phosphorus silicate glass (BPSG) is formed on the CV by CV.
It is formed by the D method or the like. Then, this first insulating film 3
Is heated at about 850 ° C. and reflowed to flatten the upper surface of the first insulating film 3. In addition, in FIG.
Illustration of various components of the semiconductor device formed on the substrate 1 is omitted.

Next, after forming various semiconductor device constituent elements on the first insulating film 3, a second insulating layer 4 made of SiO _{2 is} again formed on the first insulating film 3, and boron is again formed on the second insulating layer 4. A first insulating film 5 made of phosphosilicate glass is formed. At this time, the first insulating film 3 and the first insulating film 5
And are usually of the same composition. Next, as shown in FIG. 4B, the photoresist 6 is patterned on the first insulating film 5, and further, as shown in FIG. 4C, etching treatment is performed to form a contact hole 7. Next, the reflow process is performed again to flatten the first insulating film 5, thereby forming the insulating laminated portion A. Then, an aluminum wiring is formed in the contact hole 7 by a known method. Here, the reflow treatment of the first insulating film 5 is usually performed at a higher temperature than the reflow treatment of the first insulating film 3 described above. The insulating laminated portion A is formed only on a large number of chips formed on the wafer, and is not formed on scribe lines (streets) between the chips.

[0005]

However, the above-described method of manufacturing a semiconductor device has the following disadvantages. As described above, the insulating laminated portion A is formed by the two kinds of insulating films, and the contact hole 7 is formed in this insulating laminated portion.
Is formed, due to the difference in the thermal characteristics of the two types of insulating films, in the peripheral portion of the chip constituting the semiconductor device,
The inner wall surface 8 of the contact hole 7 as shown in FIG.
Will tilt toward the center of the chip indicated by the arrow in FIG. This is because the insulating laminated portion A is not formed in the scribe line between chips and is therefore independent for each chip. Therefore, when the reflow process is performed, the first insulating films 3 and 5 are continuous on the chip. Therefore, they are melted and pulled by the surface tension or the like so as to gather in the center direction of the chip. On the other hand, the second insulating films 2 and 4 which are not melted do not flow themselves, and the second insulating film 4 is pulled toward the center of the chip only by the flow of the lower layer, that is, the first insulating film 3. Therefore, as described above, the phenomenon in which the inner wall surface 8 is inclined as shown in FIG. 5A occurs in the contact hole 7. Here, since the melted first insulating films 2 and 4 are pulled toward the center side in the peripheral portion of the chip, the phenomenon shown in FIG. 5A is more likely to occur in the peripheral portion of the chip. There is.

Then, as shown in FIG. 5 (b), the contact hole 7 is kept in such a state that the inner wall surface 8 remains inclined.
When the aluminum wiring 9 is formed inside, the coverage of the aluminum wiring 9 is extremely deteriorated, leading to defective conduction. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a semiconductor device in which the inclination of the inner wall surface of a contact hole formed in an insulating laminated portion is eliminated, thereby preventing wiring failure. To do.

[0007]

[Means for Solving the Problems] Claim 1 in the present invention
In the method for manufacturing a semiconductor device described above, an etching step of forming a groove continuously or intermittently in the insulating laminated portion along a length direction of a peripheral portion of a chip in which the insulating laminated portion is formed, And a step of burying an insulator made of a material that is more thermally stable than the material that forms the first insulating film in the groove. The method of manufacturing a semiconductor device according to claim 2, wherein after the step of forming the contact hole, a sidewall made of a material that is more thermally stable than a material that forms the first insulating film is formed in the formed contact hole. A means for solving the above-mentioned problems is provided with a step of forming.

[0008]

According to the method of manufacturing a semiconductor device of the present invention, a groove is continuously or intermittently formed in the peripheral portion of the chip in which the insulating laminated portion is formed along the length direction of the peripheral edge thereof. Since an insulator made of a material that is more thermally stable than the material that forms the first insulating film is embedded in the formed groove, even if the reflow treatment of the first insulating film is performed thereafter. , In the periphery of the chip where the inner wall surface of the contact hole is more likely to tilt, the insulator embedded in the groove prevents the melted first insulating film from being pulled and flowing toward the center of the chip. Thereby, the inclination phenomenon of the inner wall surface of the contact hole in the peripheral portion is prevented. According to the method of manufacturing a semiconductor device of the second aspect, since the sidewall made of a material that is more thermally stable than the material that forms the first insulating film is formed in the contact hole, the first insulating film is formed thereafter. Even if the film reflow treatment is performed, the first insulating film is prevented from melting and flowing by the sidewalls, which results from the difference in thermal characteristics between the first insulating film and the second insulating film. The inclination phenomenon of the inner wall surface of the contact hole is prevented.

[0009]

EXAMPLES The present invention will be described in detail below with reference to examples. 1A to 1F are views for explaining a first embodiment of the present invention. In the first embodiment, first, FIG.
In the same manner as conventional as shown in (a) forming a second insulating layer 2 made of SiO ₂ on a silicon substrate 1, followed by a first insulating consisting of boron phosphorus silicate glass (BPSG) over this The film 3 is formed by the CVD method or the like. Here, the boron-phosphorus silicate glass forming the first insulating film 3 is adjusted and formed so as to contain 1.8 to 2.0% by weight of boron and about 7.5% by weight of phosphorus as its components. . Then, the first insulating film 3 is heated at, for example, about 900 ° C. to perform a first reflow treatment to flatten the upper surface of the first insulating film 3. In addition, also in FIG.
As in the case shown in FIG. 4, various components of the semiconductor device formed on the substrate 1 are not shown.

Next, after forming various semiconductor device constituent elements on the first insulating film 3, a second insulating layer 4 made of SiO _{2 is} again formed on the first insulating film 3, and boron is again formed on the second insulating layer 4. A first insulating film 5 made of phosphosilicate glass is formed. Here, the boron-phosphorus silicate glass forming the first insulating film 5 is adjusted and formed so that its components contain about 2.2% by weight of boron and about 7.5% by weight of phosphorus. That is, the first insulating film 5 has a higher boron content than the first insulating film 3, in other words, the first insulating film 3 has a lower boron content. As a result, the first insulating film 3 is adjusted so as to have a lower fluidity due to its melting than the first insulating film 5 in the second reflow process described later.

Next, as shown in FIG. 1 (b), a photoresist 10 is patterned on the first insulating film 5, and as shown in FIG. 1 (c), a groove 11 is formed by etching. To do. Here, the patterning of the groove 11 is performed continuously or intermittently along the length direction of the peripheral edge of the chip as shown in FIG. That is, the groove 11 may be continuously formed so as to go around the peripheral portion of the chip, or the plurality of grooves 11 may be formed intermittently and, when these are temporarily connected, the peripheral portion of the chip is formed. You may arrange so that it may go around. In addition, in FIG. 2, the arrow indicates the direction of inclination of the inner wall surface of the conventional contact hole.

A conventionally known method is adopted as the etching treatment. In addition, the peripheral portion of the chip mentioned here specifically refers to a boundary portion between the peripheral region 12 (see FIG. 2) in which the inner wall surface of the contact hole is likely to be inclined and the central region 13 in which the inclination is unlikely to occur. However, since this boundary portion differs depending on the size of the chip, the configuration of each of the insulating films 2 to 5, and the like, the position is determined by empirically obtaining in advance. Further, regarding the depth of the groove 11, it goes without saying that the insulating film 5-2 penetrates the insulating films 5-2.
(C) It may be formed so as to reach the surface layer portion of the silicon substrate 1 as indicated by the double-dashed line in the middle, and in that case, the effect of the insulator 15 described later becomes even greater.

Next, as shown in FIG. 1D, for example, a silicon oxide film 14 is deposited by the CVD method or the like, and then the entire surface is etched back to form the groove 1 formed.
As shown in FIG. 1 (e), an insulator 15 made of SiO ₂ is embedded in 1. In this example, the insulator 15 is S
Although iO ₂ was selectively formed, this insulator is more thermally stable than the material forming the first insulating films 3 and 5, that is, the insulator itself is melted during the second reflow treatment described later. Of course, other insulating materials may be selected as long as the material does not flow.

Then, the first insulating film 5 is formed in a conventional manner.
A photoresist is patterned on the above, and etching is further performed to form a contact hole. Then, again, that is, the second reflow treatment is performed to flatten the first insulating film 5, thereby forming an insulating laminated portion. Here, the second reflow treatment is performed at a temperature equal to or lower than the temperature of the first reflow treatment, specifically, at about 850 ° C.

When such a second reflow process is performed,
Although the first insulating film 5 is melted and partially flows to be flattened, the insulator 15 in the groove 11 formed earlier is not melted by the second reflow treatment, and therefore, this is the first insulating film. Since the film functions to prevent the fluidization of the films 3 and 5, the phenomenon that the inner wall surface of the contact hole is inclined especially in the peripheral portion of the chip is prevented.
Moreover, since the first insulating film 3 has already been subjected to the first reflow treatment and has been exposed to a temperature equal to or higher than the second reflow treatment temperature, the degree of melting is small in the second reflow treatment. The occurrence of the above phenomenon is further prevented. Further, the first insulating film 3 is adjusted so that the amount of boron is lower than that of the first insulating film 5 as described above, and therefore the fluidity associated with its melting is lowered, so that the first insulating film 3 is adjusted. No. 3 is hardly affected by the second reflow process, and this also prevents the occurrence of the above phenomenon. Thereafter, as shown in FIG. 1F, an aluminum wiring 17 is formed in the contact hole 16 by a known method.

In the method of manufacturing such a semiconductor device, since the insulator 15 is embedded in the groove 11, the first insulating films 3 and 5 are melted by the reflow process and flow with it. Therefore, it is possible to prevent the phenomenon in which the inner wall surface of the contact hole 16 is inclined especially in the peripheral portion of the chip, and the aluminum wiring 17 can be normally formed in the contact hole 16 without any trouble. . Moreover, since the second reflow processing temperature is set to be equal to or lower than the first reflow processing temperature,
At the time of the second reflow treatment, the degree of melting of the first insulating film 3 is small, so that the inclination of the inner wall surface of the contact hole 16 can be further prevented. Furthermore, the amount of boron in the first insulating film 3 is made lower than that in the first insulating film 5, so that the fluidity associated with heating and melting is lower in the first insulating film 3 than in the first insulating film 5. Since the first insulating film 3 is adjusted so as to be almost unaffected by the second reflow treatment, the inclination of the inner wall surface of the contact hole 16 can be further prevented by this.

FIGS. 3A to 3D are views for explaining the second embodiment of the present invention, and this second embodiment is the first embodiment.
The difference from the embodiment is that the groove 11 is not formed,
The point is that an insulator is directly provided as a sidewall in the contact hole 16. That is, in this embodiment, the contact is made to the insulating laminated portion A as shown in FIG. 3A in the same manner as in the prior art without forming the groove 11 in the first embodiment, and of course without providing the insulator 15. The hole 16 is formed.

Next, as shown in FIG. 3 (b), for example, a silicon nitride film 18 is deposited by a CVD method or the like, and then an overall etch back process is performed, so that silicon nitride is formed as shown in FIG. 3 (c). A side wall 19 made of is formed on the inner wall surface of the contact hole 16. Although silicon nitride is selectively formed as the insulator forming the sidewalls 19 in this example, this insulator is more thermally stable than the material forming the first insulating films 3 and 5, that is, will be described later. As in the case of the insulator 15 in the first embodiment, another insulator may be selected as long as it is a material that does not melt and flow in the insulator itself during the second reflow treatment. Is. Then, a second reflow process is performed in the same manner as in the first embodiment to planarize the first insulating film 5 to form an insulating laminated portion. Then, as shown in FIG. 3D, an aluminum wiring 17 is formed in the contact hole 16 by a known method.

In such a manufacturing method, the sidewall 19 made of a material that is more thermally stable than the first insulating films 3 and 5 is formed in the contact hole 16, and then the second reflow treatment is performed. Therefore, even if the first insulating films 3 and 5 melt and flow, the flow can be blocked by the sidewalls 19 that are difficult to melt by this reflow process, so that the inner wall surface of the contact hole 16 tilts. Therefore, the aluminum wiring 17 can be normally formed in the contact hole 16 without any trouble.

Further, also in the second embodiment, the second reflow processing temperature is set to be equal to or lower than the first reflow processing temperature, or the amount of boron in the first insulating film 3 is set to the first insulating film 5.
As in the case of the first embodiment, the inclination phenomenon of the inner wall surface of the contact hole 16 can be further prevented by making it lower than that of the first embodiment. However, in these first and second embodiments, the second reflow treatment temperature is set to be equal to or lower than the first reflow treatment temperature, or the amount of boron in the first insulating film 3 is lower than that in the first insulating film 5. You can make it the same as before without making it
Even in that case, by burying the insulator 15 in the groove 11 or forming the sidewall 19 in the contact hole 16, it is possible to sufficiently prevent the phenomenon that the inner wall surface of the contact hole is inclined.

[0021]

As described above, in the method of manufacturing a semiconductor device according to the first aspect of the present invention, in the peripheral portion of the chip in which the insulating laminated portion is formed, the insulating laminated body is formed along the length direction of the peripheral edge. Forming a groove in the part continuously or intermittently,
Since it is a method of embedding an insulator made of a material that is more thermally stable than the material forming the first insulating film in the formed groove, a reflow treatment of the first insulating film is performed thereafter. However, it is possible to prevent the first insulating film melted by the insulator embedded in the groove from being pulled to the center side of the chip and flowing, thereby preventing the phenomenon that the inner wall surface of the contact hole is inclined, Wiring can be done normally without any problems. The method for manufacturing a semiconductor device according to claim 2 is a method in which a sidewall made of a material that is more thermally stable than a material that forms the first insulating film is formed in the contact hole. Even if the reflow process of the first insulating film is performed, the flow of the first insulating film can be blocked by the sidewalls, so that the difference in thermal characteristics between the first insulating film and the second insulating film is caused. It is possible to prevent the phenomenon that the inner wall surface of the contact hole is inclined due to the above, and thus, the wiring can be normally performed in the contact hole without any trouble.

[Brief description of drawings]

1A to 1F are manufacturing process diagrams for explaining a first embodiment of a method of manufacturing a semiconductor device according to the present invention in the order of manufacturing processes.

FIG. 2 is an enlarged plan view for explaining positions of grooves formed on a chip.

3A to 3D are manufacturing process diagrams for explaining the second embodiment of the method of manufacturing a semiconductor device according to the present invention in the order of manufacturing processes.

4A to 4C are manufacturing process diagrams for explaining an example of a conventional method for manufacturing a semiconductor device in the order of manufacturing processes.

5 (a) and 5 (b) are manufacturing process diagrams following the process shown in FIG.

[Explanation of symbols]

 1 Silicon Substrate 2 Second Insulating Film 3 First Insulating Film 4 Second Insulating Film 5 First Insulating Film 15 Insulator 16 Contact Hole 19 Sidewall A Insulating Laminated Part

Claims (4)

[Claims] 1. An insulating laminated portion is formed by laminating a first insulating film on a substrate and a second insulating film made of a material that is thermally stable as compared with the material forming the first insulating film. In the method for manufacturing a semiconductor device in which a contact hole is formed in the insulating laminated portion, in the peripheral portion of the chip on which the insulating laminated portion is formed, the insulating laminated portion is continuously or continuously formed along the length direction of the periphery thereof. An etching step of intermittently forming a groove, and a step of burying an insulator made of a material that is more thermally stable than a material forming the first insulating film in the groove Manufacturing method of semiconductor device. 2. An insulating laminated portion is formed by laminating a first insulating film on a substrate and a second insulating film made of a material that is thermally stable as compared with a material forming the first insulating film. In the method for manufacturing a semiconductor device in which a contact hole is formed in this insulating laminated portion, in the contact hole, after the step of forming the contact hole, it is more thermally than a material forming the first insulating film. A method of manufacturing a semiconductor device, comprising a step of forming a sidewall made of a stable material. 3. The first insulating film is boron phosphosilicate glass, and at least two layers are formed with the first insulating film sandwiching the second insulating film to form the insulating laminated portion. A step of forming the insulating laminated portion on a chip, a first reflow processing step of forming a first insulating film on the substrate side of the first insulating film, and then performing a reflow processing on the first insulating film; A second reflow treatment step of forming another first insulation film formed on the first insulation film after the treatment and then performing a reflow treatment on the first insulation film, wherein the reflow treatment temperature in the second reflow treatment step is The temperature is not higher than the reflow processing temperature in the first reflow processing step.
Alternatively, the method for manufacturing the semiconductor device according to the item 2. 4. The first insulating film is boron phosphosilicate glass, and at least two layers of the first insulating film sandwich the second insulating film to form the insulating laminated portion. The content of boron in the first insulating film on the substrate side of the first insulating film, boron content of another first insulating film formed on the first insulating film 3. The method for manufacturing a semiconductor device according to claim 1, wherein the content is lower than the content rate.