JP3455442B2 - Wiring structure manufacturing method - 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 wiring structure formed on a substrate which constitutes a semiconductor device, a display device or the like. In particular, a via hole (through hole) or a wiring groove (trench) is formed in an interlayer insulating film, a metal film is deposited on the via hole, and then the metal film is removed by a chemical mechanical polishing (CMP) method, etc. The present invention relates to a method for manufacturing a wiring structure using a so-called single damascene method or dual damascene method, in which a metal is embedded in a wiring groove.

[0002]

2. Description of the Related Art In order to operate a semiconductor device in which a plurality of elements are integrated at a high speed, it is necessary to reduce a wiring resistance in order to reduce a wiring delay such as a connection between the respective elements. Therefore, recently, copper (Cu), which has a low resistivity and is easily available, has been studied for wiring. In forming the wiring structure using Cu, the single damascene method and the dual damascene method are being actively studied in order to simplify the process and reduce the cost. Less than,
An example of the dual damascene method that has been conventionally developed will be given below to briefly explain them.

Conventional Example 1 Document 1 (Japanese Laid-Open Patent Publication No. 10-112503) discloses a method of manufacturing a semiconductor device by a dual damascene method using an organic low dielectric constant film. In recent years, in a semiconductor device in which miniaturization is advanced and the degree of integration is improved, wirings are placed closer to each other. There is a need to reduce the capacity between. Therefore, as the interlayer insulating film for separating each wiring, the above-described organic insulating film having a low dielectric constant and a small dielectric constant and being easily processed is being studied.

The manufacturing method described in Document 1 will be described with reference to FIG. In this document 1, first, FIG.
As shown in (a), a silicon oxide film 602, an organic low dielectric constant film 603, and a silicon oxide film 604 are sequentially deposited on a silicon substrate 601, and a resist pattern 605 having a groove in a wiring structure forming portion is formed thereon. To do. Then, using the resist pattern 605 as a mask, the silicon oxide film 60 is formed.
By etching 4 and then removing the resist pattern 605, a groove 606 is formed in the silicon oxide film 602 as shown in FIG. 6B.

Next, as shown in FIG. 6C, a groove 606 is formed.
A resist pattern 607 having an opening to be placed inside is formed. Then, by using this resist pattern 607 as a mask, the organic low dielectric constant film 603 and the silicon oxide film 602 are selectively removed by etching, and the resist pattern 607 is removed, as shown in FIG. A contact hole 608 having a surface of the silicon substrate 601 exposed at the bottom is formed.

Next, as shown in FIG. 6E, the groove 606 is formed.
The organic low dielectric constant film 603 is selectively removed by etching using the silicon oxide film 604 having the film formed as a mask to form a wiring groove 609. At this time, the lower silicon oxide film 6
Since 02 is not etched due to the difference in material, no groove is formed in the silicon oxide film 602 and the contact hole 608 remains. Next, a wiring material is deposited on the silicon oxide film 604 including the inside of the contact hole 608 and the wiring groove 609, and then the wiring material is removed by chemical mechanical polishing (CMP) until the silicon oxide film 604 is exposed. By doing so, as shown in FIG. 6F, the wiring material 610 is formed so as to fill the contact hole 608 and the wiring groove 609. Through the steps described above, according to Conventional Example 1 described in Document 1, a wiring structure using an organic low dielectric constant film as a part of the interlayer film and using Cu as an electrode wiring material is formed.

By the way, in the above-mentioned conventional example 1, since the organic low dielectric constant film is arranged between the adjacent wirings formed in the same layer, the capacitance between the wirings can be reduced. For example, the capacitance between the wiring and the substrate is not reduced so much. Here, the following Document 2 (monthly Semiconducto
In the technology described in r World (January 1998 issue, pages 108 to 114), an organic low dielectric constant film is used for almost all interlayer films.

Conventional Example 2 First, according to one technique described in Document 2, FIG.
, A silicon nitride film 701, a low dielectric constant film 70 is formed on a base layer (omitted) such as a silicon substrate.
2, a silicon oxide film 703, a low dielectric constant film 704, and a silicon oxide film 705 are sequentially deposited, and a photoresist pattern 706 having an opening at a desired position is formed.
Next, using the photoresist pattern 706 as a mask, the silicon oxide film 705, the low dielectric constant film 704, the silicon oxide film 703, and the low dielectric constant film 702 are selectively removed.
By removing the photoresist pattern 706, as shown in FIG.
As shown in (b), a via hole 707 is formed.

Next, a new photoresist is applied on the silicon oxide film 705 including the via hole 707 forming portion, and the electrode wiring pattern is exposed and developed, whereby the structure shown in FIG.
As shown in (c), a photoresist pattern 708 having a groove formed in a desired region for forming a wiring structure is formed. At this time, as shown in FIG.
The exposure amount and the development amount for forming the photoresist pattern 708 described above are controlled so that the photoresist pattern 708 remains on the bottom of 07. Next, using the photoresist pattern 708 as a mask, the silicon oxide film 705 is selectively etched to form a groove in the silicon oxide film 705, as shown in FIG. 7D.

Next, after removing the photoresist pattern 708, this time, a silicon oxide film 705 having a groove is formed.
The low dielectric constant film 704 is selectively removed by using the mask as a mask, and the wiring groove 70 is formed in the low dielectric constant film 704 as shown in FIG.
9 is formed. At this time, the silicon oxide film 703 serves as an etching stopper and no groove is formed in the low dielectric constant film 702. Next, the silicon nitride film 70 is formed using the silicon oxide film 703 having the via holes 707 as a mask.
1 is selectively etched, and as shown in FIG.
A via hole 710 reaching the surface of a silicon substrate (not shown) under the silicon film 701 is formed.

After that, the via hole 710 and the wiring groove 709 are filled with a wiring material to form a wiring structure connected to the silicon substrate, and the dual damascene process is completed. In comparison with the above-mentioned conventional example 1, in this conventional example 2, the silicon oxide film 7 shown in FIG.
03 (a silicon nitride film may be used) to form different patterns on the upper and lower low dielectric constant films. That is, the conventional example 2 is characterized in that the silicon oxide film 703 plays a role of an etching stopper layer to form patterns of different shapes on the upper and lower low dielectric constant films.

Conventional Example 3 Next, a third conventional example will be described with reference to FIG. This conventional example 3 is an example in which a via hole and a wiring groove are formed in a single low-k film. First, as shown in FIG. 8A, although not shown, a silicon nitride film 801, a low dielectric constant film 802, and a silicon oxide film 803 are sequentially deposited on a base layer such as a silicon substrate, and a via hole is formed. A photoresist pattern 804 having an opening is formed at the place to be formed. Then, using the photoresist pattern 804 as a mask, a silicon oxide film 803 and a low dielectric constant film 802 are formed.
Selectively etch the photoresist pattern 8
By removing 04, a via hole 805 is formed as shown in FIG.

Next, a photoresist is applied, the electrode wiring pattern is exposed and developed, and as shown in FIG. 8C, a photoresist pattern 8 having a groove corresponding to the wiring formation region is formed.
06 is formed. Next, the photoresist pattern 80
6 is used as a mask to selectively etch the silicon oxide film 803, and as shown in FIG.
The groove is formed in 03. Next, after removing the photoresist pattern 806, the low dielectric constant film 802 is selectively removed halfway using the silicon oxide film 803 in which the groove is formed as a mask, as shown in FIG.
A wiring groove 807 is formed in the low dielectric constant film 802.

Then, as shown in FIG. 8F, the silicon nitride film 801 exposed at the bottom of the via hole formed in the wiring trench 807 is removed, and as shown in FIG. A via hole 808 reaching a silicon substrate (not shown) is formed. After that, if the wiring material is buried in the wiring groove 807 and the via hole 808 as in the case of the conventional example 1 described above, the wiring connected to the silicon substrate through the via hole is formed, and the dual damascene process is completed. In Conventional Example 3, the interlayer insulating film is formed of one layer, and the process is simplified.

[0015]

However, the above-mentioned conventional method has the following problems. As can be seen from the above-mentioned conventional examples 1 to 3, when a wiring structure is formed by a damascene process using a low dielectric constant film as an interlayer film, grooves and holes for forming wiring in the low dielectric constant film are often used. It is formed by using a known processing technique including photolithography technique and etching technique. That is, a photoresist pattern is formed on the oxide film made of an inorganic material by using a photolithography technique,
This photoresist pattern is used to pattern an oxide film, and the patterned low-dielectric-constant film is used as a mask to pattern the lower dielectric constant film.

Since the low dielectric constant film is an organic material, it is difficult to perform selective etching using a photoresist pattern, which is a similar organic material, as a direct mask. Therefore, as described above, once the pattern of the inorganic material oxide film is formed. It is formed, and the low dielectric constant film is processed using this as a mask. Then, the photoresist is used only for patterning the oxide film, and is removed when it finishes its role.
Further, in the above-mentioned conventional examples 1 and 2, the connection groove and the wiring groove are formed by the damascene process (dual damascene). In order to form such different patterns, a silicon oxide film or a silicon nitride film to be an etching stopper layer is required in the middle of the low dielectric constant film. Therefore, in the related arts 1 and 2, the number of steps is increased, and in addition, the number of manufacturing apparatuses is increased, which leads to an increase in cost.

On the other hand, in Conventional Example 3, two patterns are formed without using the etching stopper layer. However, dry etching using plasma is performed for processing the low dielectric constant film which is an organic material. I am trying to use it. Thus, when the processing of the organic material is performed by the plasma treatment, as described in the above-mentioned Document 2,
There is a problem that the reaction product generated by the plasma treatment adversely affects the processed shape of the hole or groove.

The present invention has been made to solve the above problems and uses an interlayer film made of an organic material having an insulating property without being adversely affected by a reaction product generated by plasma treatment. It is an object of the present invention to be able to be manufactured in a smaller number of steps than the conventional wiring structure.

[0019]

A method of manufacturing a wiring structure according to the present invention comprises a step of forming a resin layer made of an organic material having photosensitivity on a substrate and a predetermined amount of ultraviolet rays of a predetermined amount in a predetermined region of the resin layer. A step of forming a latent image on the resin layer by irradiating for a time, a step of developing the latent image to form a recess in the resin layer, and a step of forming a conductive film made of a conductive material on the resin layer including the recess And a step of removing the conductive film from the surface to form a wiring structure in which the recesses are filled with a conductive material, and the latent image is formed in a predetermined region of the resin layer with a predetermined amount of light of a purple color.
An opening that reaches the substrate surface by irradiating it with an external wire for a predetermined time
Of forming a first latent image for forming a portion on a resin layer
And a region including the first latent image forming region of the resin layer,
A certain amount of purple light is emitted in a certain area of the depth that does not reach the substrate surface.
A place where an opening is formed by irradiating an outside line for a predetermined time
To form a groove in the resin layer that extends through in the specified direction
And a step of forming a second latent image for
The recess is composed of an opening and a groove, and the resin layer is illuminated by light.
Where it was Isa was in so that is removed in the development. Since the manufacturing is performed as described above, the concave portion of the interlayer film in which the wiring structure is embedded is formed by the photolithography technique for directly processing the interlayer film, and for example, the interlayer film made of the resin layer is formed on the substrate through the interlayer film. The wiring structure is placed.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First Embodiment First, a first embodiment of the present invention will be described with reference to FIG.
Will be described with reference to FIG. The first embodiment is applied to the dual damascene method. First, FIG. 1 (a)
As shown in FIG. 5, a photosensitive resin is applied onto the substrate 101 having the electrode pad 103 and the insulating layer 102 by spin coating or the like, and prebaked to evaporate the solvent to dry the resin. The photosensitive resin layer 104 is formed. As the photosensitive resin forming the photosensitive resin layer 104, a positive type obtained by adding a positive type photosensitive agent (diazonaphthoquinone or the like) to a base resin using polyimide, polyamic acid, polybenzoxazole (PBO) or the like as a substrate. A photosensitive resin is used. Naturally, the photosensitive resin layer 104 is an insulating material, and the photosensitive resin described below has an insulating property.

With respect to the positive type photosensitive resin containing PBO as a base resin, good results were obtained by using, for example, CRC8300 (trade name) manufactured by Sumitomo Bakelite Co., Ltd. In the case of this CRC8300, prebaking such as evaporation of the solvent may be performed by placing the substrate coated with it on a hot plate heated to 120 ° C. for about 4 minutes. It is characteristic that such a photosensitive resin has a low relative dielectric constant of about 2.5 to 3.0 after being hard-baked (high-temperature heat treatment) at about 300 ° C. Next, as shown in FIG. 1B, a first photomask 105 having a pattern for forming a desired via hole is used, and an ultraviolet ray 106 is applied to the photosensitive resin layer 104 through the first photomask 105. Exposure is performed to form a first latent image 107, which will be a via hole, on the electrode pad 103.

Here, the exposure process will be described in more detail. First, the first photomask 105 used is
A pattern serving as a via hole composed of a light transmitting portion is formed at a desired portion, and a mask alignment mark is formed, for example, in the peripheral portion. That is, the first
In the photomask of, a light-shielding film made of a metal film such as chrome is formed on a transparent substrate made of synthetic quartz or the like.
The pattern formed of the above-mentioned light transmitting portion is formed at a predetermined position of the light shielding film. In addition, here
Since the positive type photosensitive resin is used, the pattern of the photomask is composed of the light transmitting portion. On the other hand, in the case of using a negative photosensitive resin, for example, a photomask in which a pattern is composed of a light shield made of a metal film of chromium or the like is used on a transparent substrate made of synthetic quartz or the like. Good.

At the time of exposure, the pattern forming surface of the first photomask 105 is placed close to the photosensitive resin layer 104 forming surface. At this time, by setting the positional relationship between the substrate alignment mark formed on the substrate 101 and the mask alignment mark described above to a predetermined state, the relative positional relationship between the substrate 101 and the first photomask 105 is set to a predetermined state. And As a result, the position of the pattern to be the via hole formed in the first photomask 105 overlaps the position of the photosensitive resin layer 104 where the via hole is to be formed. After performing the above alignment,
The first latent image 107 can be formed by irradiating the surface of the first photomask 105 on which the pattern is not formed with ultraviolet rays 106 and transferring the pattern to the photosensitive resin layer 104.

Next, the first latent image 107 is developed and the image shown in FIG.
As shown in (c), a via hole 108 is formed in the photosensitive resin layer 104. Here, since the positive type CRC8300 is used as the photosensitive resin layer 104 in the first embodiment, a developer of an alkaline aqueous solution is used. In addition,
Use a developing solution suitable for each photosensitive resin used. Next, the photosensitive resin layer 104 in which the via hole 108 is formed is cured. This curing treatment is a step of curing the resin and removing the photosensitizer by performing hard baking at a high temperature. CRC830
In the case of 0, heating at 150 ° C. for 30 minutes under a nitrogen atmosphere,
Subsequently, heating is performed at a temperature of 310 ° C. to 320 ° C. for 30 minutes.

Next, as shown in FIG. 1 (d), a photosensitive resin is applied by spin coating or the like on the resin layer 109 which has been cured to lose its photosensitivity, and this is prebaked to evaporate the solvent. Then, the second photosensitive resin layer 110 is formed by drying. Next, as shown in FIG. 1E, a second photomask 111 having a pattern for forming a desired electrode wiring is used, and the ultraviolet ray 11 is applied to the photosensitive resin layer 110 through the second photomask 111.
2 is exposed, and a second latent image 113 that serves as a groove for forming an electrode wiring is formed so as to pass over the electrode pad 103. Then, by developing the second latent image 113, as shown in FIG. 2 (f), the wiring trench in the photosensitive resin layer 11 0 1
14 is formed. Again, because of the use of CRC8300 the positive and the photosensitive resin layer 11 0, using the developer an aqueous alkali solution. At this time, since the resin layer 109 is cured, it has no photosensitivity and the photosensitive resin layer 1
It is hardly deformed in the exposure and development of the 1 0.

Next, a hardening process is performed in the same manner as the hardening process of the resin layer 109 described above, and as shown in FIG.
A via hole 108 is arranged on the electrode pad 103, and a low dielectric constant resin layer 115 in which a wiring groove 114 is arranged so as to pass therethrough is formed. Next, as shown in FIG. 2H, a metal layer 116 is thinly formed to have a thickness of about 100 nm on the low dielectric constant resin layer 115 including the via hole 108 and the wiring groove 114 by, for example, a sputtering method. A wiring material film 117 made of copper is formed on the metal layer 116 by a plating method. However, before this plating, a thin copper film is formed as a seed layer on the surface of the metal layer 116 by a sputtering method. The wiring material 117 is not limited to copper, but aluminum, gold, silver, or the like can be used. Further, the method is not limited to the plating method, and other film forming methods such as a sputtering method, a CVD method, or a fluidizing method may be used.

The metal layer 116 is used as a barrier film for preventing the diffusion of copper or the like and the movement of other elements, for example. Further, it is formed in order to improve the adhesion between the low dielectric constant resin layer 115 and the wiring material film 117.
As the metal layer 116, an optimum one may be selected depending on the type of wiring material used. Here, a laminated film in which a TiN film is formed on the Ti film may be used. In addition, W that can prevent the diffusion of copper,
Other materials such as WN, Ta, and TaN may be used. By the way, as described above, when the wiring material layer 117 is formed by the plating method, the metal layer 116 can be used as a seed layer depending on the combination of materials used.

Next, as shown in FIG. 2 (i), a part of the metal layer 116 and the wiring material layer 117 are ground and removed by chemical mechanical polishing (CMP) to remove the low dielectric constant resin. The via hole and the wiring groove of the layer 115 are filled with the wiring material, and the electrode wiring 118 is formed by a so-called dual damascene method. Here, in CMP, a polishing solution (slurry) in which hydrogen peroxide (H ₂ O ₂ ) is mixed with a polishing agent containing alumina as a main component is used. As a result, the polishing rates of the low dielectric constant resin layer 115, the wiring material layer 117, and the metal layer 116 become substantially equal, and the surface of the low dielectric constant resin layer 115 and the surface of the electrode wiring 118 have substantially the same height ( The difference can be less than 0.1 μm).

As described above, according to the first embodiment, unlike the prior art, the electrode pad 103 serves as an interlayer film in a shorter process and without using plasma processing for processing the organic material. Wiring structure in which the electrode wiring 118 is connected through the low dielectric constant resin layer 115 (FIG. 2 (i))
Can be formed. Although the positive photosensitive resin is used in the first embodiment, a negative photosensitive resin obtained by adding a negative photosensitive agent to polyimide or benzocyclobutene (BCB) may be used. . in this way,
When the negative photosensitive resin is used, the relationship between the light shielding portion and the light transmitting portion of the pattern of the photomask described above may be reversed.

The advantages and disadvantages of the positive type and negative type photosensitive resins used as the interlayer film will be described below. First, a feature of using a positive photosensitive resin is that after development, the holes and grooves have a stronger tendency to open toward the top (edges have a positive taper). This is because the ultraviolet ray transmittance of the photosensitive resin layer is not 100%, so that the amount of exposure is higher in the upper portion of the resin layer during exposure for pattern formation. Further, the dissolution of the resin due to development from the upper side also increases the tendency of the positive taper. In particular, a positive photosensitive resin of a type that increases the transmittance when irradiated with ultraviolet rays (for example, CRC8300)
Has a strong positive taper.

This positive taper is extremely important in the wiring forming process. When a material having a low resistivity such as Cu, Au, or Ag is used as the wiring material, a barrier film is formed in the hole or groove as described above in order to suppress the diffusion of these materials into the interlayer insulating film or the like. It is necessary to keep it. When depositing this barrier film by a sputtering method, a film forming method using plasma, or the like, if the holes and grooves are positive taper, a film that is not extremely thin compared to the top surface and bottom surface is deposited on the side walls thereof. It is possible. However, if the taper is inversely tapered, the barrier film on the side wall must be extremely thin, which causes the barrier effect to be significantly deteriorated.

On the other hand, in the negative type photosensitive resin, the mechanism for light is reversed, and therefore when the holes or grooves are formed in the negative type photosensitive resin, reverse taper is likely to occur. Therefore, when the negative photosensitive resin is used, the barrier film may not be thickly formed on the side wall of the hole or groove. For this reason,
When using a negative photosensitive resin, it is important to select a resin that does not have a taper angle as much as possible. However, since it may be convenient to form the wiring structure by utilizing the inverse taper, this is not the case. For example, when it is desired to form a gate electrode having a reverse taper, it is convenient to use a negative photosensitive resin.
A representative example of the low dielectric constant negative photosensitive resin is BCB having photosensitivity. This material has a low dielectric constant (approximately 2.
5) is obtained. In addition, the relative permittivity after curing of CRC8300, which is the positive photosensitive resin used in the above-described first embodiment, is about 2.9.

Second Embodiment Next, a second embodiment of the present invention will be described.
The second embodiment is a method in which the first curing process of the photosensitive resin in the first embodiment is replaced with a simpler process, and the via hole and the wiring groove can be formed by one curing process. is there. As described above, in the first embodiment,
In order to eliminate the photosensitivity of the first photosensitive resin layer 104 (FIG. 1C), heat treatment at high temperature, so-called curing treatment was performed.

A heating furnace is usually used for this curing treatment. In order to prevent oxidation, a photosensitive resin based on polyimide, polyamic acid, PBO, BCB, etc.
The curing treatment needs to be performed in an atmosphere of an inert gas such as nitrogen gas. Therefore, after the substrate to be heat-treated is loaded in the heating furnace, the inside of the furnace must be purged with an inert gas for a long time. Also, since the heating furnace has a large heat capacity,
A long time is required for heating and cooling. Under such circumstances, the curing process requires a long processing time. Then, after various experiments, the inventors found a method of rapidly eliminating the photosensitivity of the first photosensitive resin layer 104 in the first embodiment described above by the following.

In the second embodiment, in order to quickly eliminate the photosensitivity of the first photosensitive resin layer 104, heat treatment is performed at a relatively low temperature in the air using a hot plate or the like. Here, FIG. 3 shows the relationship between the heat treatment temperature of the photosensitive resin film after once exposed and developed, and the film thickness change when the exposure and development treatment is performed again after the heat treatment. Here, the above-mentioned CRC8300 is applied, the solvent is dried by prebaking to form a photosensitive resin film on the substrate, exposure (ultraviolet rays) for transferring a predetermined pattern to the photosensitive resin film is performed, and this is developed. The dried product was heated in the air at 150 ° C. to 210 ° C. for 10 minutes and used as the initial state. The heating was performed by placing the substrate on a hot plate set to a predetermined temperature.

Then, in the photosensitive resin film in the initial state,
This time, the entire area is irradiated with the same amount of UV light,
Similarly, the film was developed and dried, and the change in the film thickness of the remaining film portion of the photosensitive resin film in the initial state was measured. As can be seen from FIG. 3, when the set temperature of the hot plate is 170 ° C. or higher, the reduction of the film does not occur due to the second exposure and development. That is, 170 ℃ by hot plate
It can be seen that the above heating causes the CRC8300 to lose its photosensitivity. The cause of the loss of the photosensitivity of CRC8300 by this heat treatment is considered to be, for example, the evaporation of the photosensitizer, the decrease in the solubility in the developer due to other chemical changes, or the influence of oxidation.

The photosensitivity lost by the heating by the hot plate is not limited to the above-mentioned CRC8300, and the temperature at which the photosensitivity disappears by the heating by the hot plate varies depending on the type of the photosensitive resin used. Conceivable. As described above, the photosensitive resin used in the first embodiment can eliminate the photosensitivity without performing the curing treatment at a high temperature.
It is not necessary to perform the time-consuming curing treatment of the photosensitive resin layer 104 described in (d). That is, it is sufficient that the photosensitive resin layer 104 has lost its photosensitivity before the second photosensitive resin layer 110 is formed, and the photosensitive resin film 104 needs to be cured. Because there is no.

Therefore, in the second embodiment, as shown in FIG.
After forming the via holes 108 in the photosensitive resin layer 104, as shown in FIG.
The photosensitivity of the photosensitive resin layer 104 is lost by the treatment of heating to 0 ° C. or higher. Then, as shown in FIG. 1D, a photosensitive resin is applied onto the resin layer 109 having lost its photosensitivity by spin coating or the like, and prebaked to evaporate the solvent to dry the resin. The second photosensitive resin layer 110 was formed. The subsequent process is similar to that of the first embodiment. As a result, according to the second embodiment, it is not necessary to carry out the curing treatment of the photosensitive resin layer 104 before the formation of the photosensitive resin layer 110, so that the process time is shortened as compared with the first embodiment. It becomes possible to do.

Third Embodiment Next, a third embodiment of the present invention will be described. In the third embodiment, the photosensitive characteristics of the positive type photosensitive resin are utilized to form the wiring groove and the via hole in the low dielectric constant resin layer by a single coating, developing and curing process.
First, as shown in FIG. 4A, a positive type photosensitive resin layer 204 is formed on a substrate 201 having an electrode pad 203 or an insulating layer 202 by spin coating or the like, prebaked and dried. These are the same as those in the first embodiment, and for example, CRC8300 manufactured by Sumitomo Bakelite Co., Ltd. was used as the positive photosensitive resin.

Next, as shown in FIG. 4B, a first photomask 205 having a pattern for forming a desired via hole is used, and a photosensitive resin layer 204 is formed through the first photomask 205. The ultraviolet ray 206 is exposed to form a first latent image 207, which is a via hole on the electrode pad 203. The photolithography technique for forming this latent image is also the same as in the first embodiment. However, in the formation of the first latent image 207, the amount of ultraviolet light that exposes the residual film of the positive photosensitive resin in the via hole portion to zero is exposed by the subsequent development processing.

Subsequently, as shown in FIG. 4C, this time, a second photomask 208 having a pattern for forming a desired electrode wiring is used, and the photosensitive resin is passed through the second photomask 208. UV light again on layer 204
9 is exposed, and a second latent image 210 which will be a groove for forming an electrode wiring is formed so as to pass over the electrode pad 203. Here, in the formation of the second latent image 210, the exposed positive type photosensitive resin is exposed to an amount of ultraviolet rays that leaves a desired film thickness by the subsequent development processing.

Next, the first latent image 2 formed by exposure
By developing 07 and the second latent image 210, the image shown in FIG.
As shown in FIG. 3, a wiring groove 211 and a via hole 212 are formed in the photosensitive resin layer 204. Here, also in the third embodiment, the photosensitive resin layer 204 is used as the positive CRC.
Since 8300 is used, an alkaline aqueous solution is used. Then, after the photosensitive resin layer 201 is subjected to a curing treatment, as shown in FIG. 5E, on the cured low dielectric constant resin layer 213, in the same manner as in the above-described first embodiment,
The metal layer 214 is thinly formed, and in addition, the wiring material 215 is formed.

Next, as in the first embodiment, as shown in FIG. 5 (f), a portion of the metal layer 214 and the wiring material layer 215 are ground and removed by CMP to remove the low dielectric constant. The via hole and the wiring groove of the resin layer 213 are filled with the wiring material, and the electrode wiring 216 is formed by a so-called dual damascene method. As described above, according to the method according to the third embodiment as well, unlike the conventional method, a shorter process and a low dielectric constant as an interlayer film for the electrode pad can be achieved without using plasma processing for processing the organic material. It is possible to form a wiring structure in which the electrode wiring is connected via the resin layer. Further, according to the third embodiment, the process can be further shortened as compared with the above-described first and second embodiments.

In the third embodiment, in particular, the photosensitive characteristics of the positive type photosensitive resin described below are utilized. That is, in the positive photosensitive resin suitable for the third embodiment, most of the exposure light is absorbed on the surface side of the resin when the ultraviolet light is not exposed, and thus the ultraviolet light transmittance is low. However, in the region once exposed to ultraviolet rays, the transmittance of ultraviolet rays is gradually increased according to the exposure amount so that the ultraviolet rays reach a deep portion of the positive photosensitive resin layer by sufficient irradiation of ultraviolet rays. It has the characteristic that it will be exposed to ultraviolet light.

Because of having such characteristics, the positive photosensitive resin (CRC83) used in the first to third embodiments described above is used.
No. 00) has a relatively good controllability of the remaining film thickness with respect to the exposure amount, and therefore, it is easy to obtain a desired remaining film thickness by development.
When this type of positive type photosensitive resin is used, when forming the above-mentioned first latent image 207, a sufficient amount of ultraviolet light is exposed to the lower part of the photosensitive resin layer 204, and the next When the second latent image 210 of 2 is formed, the via hole is partially formed by exposing the photosensitive resin layer 204 to an ultraviolet ray that is exposed to the middle (desired depth), and at the same time, the wiring groove is relatively formed. It can be formed with good controllability of the film thickness.

By the way, in the above-described third embodiment,
The exposure wavelength at the time of forming the first latent image 207 and the second latent image 21
The controllability of the remaining film thickness with respect to the exposure amount of the resin in the second latent image 210 can be further improved by changing the exposure wavelength at the time of forming 0. For example, the CRC8
In the 300 positive type photosensitive resin, the transmittance of light having a wavelength of about 350 to 500 nm changes due to exposure to ultraviolet light. That is, the transmittance of light of about 350 to 500 nm is poor when it is not exposed to ultraviolet rays, but the transmittance of light in that wavelength band is improved when the ultraviolet rays are sufficiently exposed. However, the transmittance of light having a wavelength of less than about 350 nm does not improve even after exposure.

Therefore, in the above-described third embodiment, first, in FIG. 4B, when forming the first latent image 207, the exposure is carried out using ultraviolet rays of about 350 to 500 nm. When the light in this wavelength range is irradiated, the transmittance of the exposure light in the photosensitive resin layer 204 is gradually improved and the exposure light reaches the bottom, so that the bottom of the latent image 207 reaches the electrode pad 203. You can Then, in forming the second latent image 210, about 350 nm
The ultraviolet rays of the following wavelength bands are exposed. About 350
With ultraviolet rays in the wavelength band of nm or less, the transmittance is poor and this is not improved even by exposure, so that the exposure light does not reach the inside of the photosensitive resin layer 204 so much. Therefore, if the second latent image 210 is formed by exposure to ultraviolet light having a wavelength band of about 350 nm or less, the depth of the second latent image 210 can be reduced without strict control of the exposure amount. It can be in a substantially constant state.

By the way, in order to change the wavelength band for exposure as described above, for example, a high pressure mercury lamp is used as an exposure light source, and an optical filter is inserted in the optical path to selectively transmit ultraviolet rays having a wavelength of 350 nm or less. You can do it like this. As the optical filter, there are a filter that absorbs a wavelength band other than the desired wavelength band and a filter that reflects a wavelength band other than the desired wavelength band. As is well known, a reflection type filter can be obtained by optically designing and creating a multilayer film in which a plurality of films having different optical constants are laminated. In addition, when ultraviolet rays having a too short wavelength are used when forming the second latent image, the portion irradiated with the ultraviolet rays may be cured. Therefore, when the wavelength is shorter than 350 nm, the photosensitive resin layer is not cured so much. It is better to use a wavelength in a range that does not.

By the way, in the third embodiment, the positive type photosensitive resin is used, but it is also possible to use the negative type photosensitive resin. When a negative photosensitive resin is used, the latent image corresponding to the second latent image may be formed first, and then the latent image corresponding to the first latent image may be formed. in this case,
First, a first negative latent image that is the reverse of the second latent image shown in FIG. 3C is formed. In the formation of this first negative latent image,
Exposure is performed by reversing the relationship between the light transmitting portion and the light shielding portion of the mask. As a result, the first negative latent image forming region other than the groove forming portion is irradiated with the exposure light and is photo-cured, and the first negative latent image forming region becomes insoluble in the developing solution. That is, when a negative type photosensitive resin is used, for example, the wiring groove forming portion becomes an unexposed (unexposed) region.

If development is carried out in this state, the groove forming portions other than the first negative latent image are selectively removed. At the time of this development, the development time is set so that the unexposed negative photosensitive resin layer remains. Adjust within a shorter range than usual. As a result, wiring grooves are formed in the negative photosensitive resin layer. And this time,
A second negative latent image corresponding to the first latent image described above is formed. Also in the formation of the second negative latent image, the exposure is performed by reversing the relationship between the light transmitting portion and the light shielding portion of the mask for forming the first latent image. As a result, the second negative latent image forming area is irradiated with the exposure light to be photo-cured and becomes insoluble in the developing solution.

If development is carried out in this state, this time, the via hole forming portion other than the second negative latent image of the remaining negative type photosensitive resin layer is selectively removed. As a result,
In the negative photosensitive resin layer, a wiring groove in a region other than the first negative latent image and a through hole in a region other than the second negative latent image are formed. However, in the method using the negative photosensitive resin, the wiring groove formation is controlled by, for example, the development time. Therefore, this method and the third embodiment described above are used.
As compared with the method using the positive type photosensitive resin as described above, the controllability of the wiring groove formation is superior when the positive type photosensitive resin is used.

By the way, in the above description, the same-magnification exposure method in which the photomask is disposed close to the exposure target is used to form the latent image, but the present invention is not limited to this, and a mirror or lens is used. The projection exposure method may be a projection exposure method of projecting an image, or the reduction projection exposure method of projecting a reduced optical image. Further, in the above, after forming the through hole and the wiring groove in the photosensitive resin layer as the interlayer film,
The so-called dual damascene process of filling them with a metal material has been described as an example, but the present invention is not limited to this. It is applied to so-called single damascene, which forms only holes and then fills them with metal material to form plugs, or forms only wiring grooves and fills them with metal material to form wiring only. May be. Even in this single damascene process, the number of processes can be reduced and the cost can be reduced as compared with the conventional method.

Also, for example, the electrode pad 10 shown in FIG.
The presence or absence of 3 and the insulating layer 102 is not directly related to the present invention. Further, the type and shape of the substrate, or the presence or absence of the mounting of an integrated circuit or the like are not directly related to the present invention. Further, the application of the photosensitive resin is not limited to spin coating, and another method such as a spray coating method may be used as long as it is a method capable of applying a uniform thickness. Further, by appropriately changing the pattern of the photomask and repeating the steps according to the present invention described above, the multilayer wiring can be easily formed. In the above embodiment, the case where the resin having heat resistance of 300 ° C. or higher is used as the substrate has been described. However, other processes for forming the wiring structure are performed at a low temperature, and in addition, the wiring structure itself is When heat resistance is not required so much, a photosensitive resin using a resin having low heat resistance such as novolac resin as a substrate may be used.

When an organic resin layer is used as an interlayer insulating film, the stress of the film is small and cracks are less likely to occur, so that the thickness can be increased. Even when the organic resin layer is spin-coated, the thickness after curing can be increased. It is possible to form one layer with a thickness of 10 μm or more. Therefore, the electrode wiring having a thickness of 10 μm or more can be formed. When a photosensitive resin having a reduced viscosity is rotated at a high speed and spin-coated, a thin photosensitive resin layer having a thickness of about 1 μm or less can be applied. In this case, if reduction projection exposure using a short-wavelength light source is used, a fine pattern can be obtained by developing a photosensitive resin, and a multilayer wiring of a fine / highly integrated integrated circuit using a single crystal silicon substrate. It can also be used for the production of In this case, a large reduction in manufacturing cost and high speed operation of the integrated circuit are possible. The relative permittivity of the photosensitive resin having a reduced permittivity is about 2.5 to 3.0, and a metal such as Cu or Au having a low resistivity is used for the electrode wiring, and the damascene or By using the dual damascene process, it is possible to form a multi-layer wiring excellent in high frequency characteristics, a coil having a large Q value, and the like.

[0055]

As described above, according to the present invention, the step of forming a resin layer made of a photosensitive organic material on a substrate and irradiating a predetermined region of the resin layer with a predetermined amount of ultraviolet rays for a predetermined time. A step of forming a latent image on the resin layer, a step of developing the latent image to form a recess in the resin layer, a step of forming a conductive film made of a conductive material on the resin layer including the recess, and a conductive film Of the latent image by removing from the surface to form a wiring structure in which the recesses are filled with a conductive material .
It is formed by applying a predetermined amount of ultraviolet light to a predetermined area of the resin layer at a predetermined time.
The resin layer has an opening that reaches the substrate surface by irradiating
A step of forming a first latent image for forming the resin layer,
An area including the first latent image forming area, reaching the substrate surface
When a predetermined amount of ultraviolet light is applied to a predetermined area of a depth that cannot be reached
By passing through the area where the opening is formed by irradiating
Second for forming a groove extending in a fixed direction in the resin layer
And a step of forming a latent image of
Where the resin layer is exposed to light
There was so that removed by development. Since the manufacturing is performed as described above, the groove of the interlayer film in which the wiring structure is embedded is formed by the photolithography technique of directly processing the interlayer film, and for example, the interlayer film formed of the resin layer is formed on the substrate. And the wiring structure is placed. As a result, according to the present invention, it is possible to form the concave portion of the interlayer film in which the wiring structure is embedded without using a process other than the photolithography process such as dry etching, and therefore, without using an etching mask or an etching stopper layer. Further, there is an effect that it can be manufactured in a smaller number of steps than a wiring structure using an interlayer film made of an insulating organic material without being adversely affected by a reaction product generated by plasma treatment.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a method of manufacturing a wiring structure according to a first embodiment of the invention.

FIG. 2 is an explanatory diagram showing the method of manufacturing the wiring structure according to the first embodiment of the invention, following FIG. 1;

FIG. 3 is a characteristic diagram showing a photosensitivity characteristic of CRC8300.

FIG. 4 is an explanatory diagram showing a method of manufacturing a wiring structure according to a third embodiment of the present invention.

FIG. 5 is an explanatory view showing the method of manufacturing the wiring structure according to the third embodiment of the invention, following FIG. 4;

FIG. 6 is an explanatory diagram showing a method of manufacturing a wiring structure of Conventional Example 1.

FIG. 7 is an explanatory diagram showing a method for manufacturing a wiring structure of Conventional Example 2.

FIG. 8 is an explanatory diagram showing a method of manufacturing a wiring structure of Conventional Example 3.

[Explanation of symbols]

101 ... Substrate, 102 ... Insulating layer, 103 ... Electrode pad,
104, 110 ... Photosensitive resin layer, 105 ... First photomask, 106, 112 ... Ultraviolet ray, 107 ... First latent image, 108 ... Via hole, 109 ... Resin layer, 111 ... Second photomask, 113 ... Second latent image, 114 ... Wiring groove, 115 ... Low dielectric constant resin layer, 116 ... Metal layer, 117
... Wiring material film, 118 ... Electrode wiring.

Continuation of the front page (56) Reference JP-A-6-140520 (JP, A) JP-A-4-162642 (JP, A) JP-A-4-31860 (JP, A) JP-A-11-274121 (JP , A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/28-21/288 H01L 21/3205-21/3213 H01L 21/768

Claims (9)

(57) [Claims] 1. A latent image is formed on the resin layer by forming a resin layer made of an organic material having photosensitivity on a substrate, and irradiating a predetermined region of the resin layer with a predetermined amount of ultraviolet rays for a predetermined time. The step of developing the latent image to form a recess in the resin layer, forming a conductive film made of a conductive material on the resin layer including the recess, and forming the conductive film from the surface. And removing the conductive material to form a wiring structure in which the recesses are filled , the latent image is formed by irradiating a predetermined region of the resin layer with a predetermined amount of ultraviolet rays for a predetermined time.
The opening that reaches the surface of the substrate by
A step of forming a first latent image for forming a layer, and an area including the first latent image forming area of the resin layer.
A predetermined area at a depth that does not reach the substrate surface.
The opening is shaped by irradiating a certain amount of ultraviolet light for a predetermined time.
In front of the groove that extends in the specified direction passing through the place to be formed
And a step of forming a second latent image for forming on the resin layer.
At least, the recess is composed of the opening and the groove, and the resin layer is removed by the development where light is irradiated.
Method for manufacturing a wiring structure, characterized in that it is. 2. The method of manufacturing a wiring structure according to claim 1 , wherein the wavelength band of ultraviolet rays for forming the second latent image is the
The above-mentioned wavelength range of ultraviolet rays for forming the first latent image
A method of manufacturing a wiring structure, which is in a wavelength band that is difficult to pass through a resin layer . 3. The method of manufacturing a wiring structure according to claim 2 , wherein the wavelength band for forming the second latent image is the first latent image.
A method of manufacturing a wiring structure, wherein the wavelength band is shorter than a wavelength band for forming an image . 4. The method of manufacturing a wiring structure according to claim 1 , wherein the second latent image is formed after forming the first latent image.
Method for manufacturing a wiring structure, characterized in that that. 5. A method according to claim 1-3 method of manufacturing a wiring structure according to any one of interconnect structure and forming a first latent image after formation of the second latent image Production method. 6. The wiring structure according to any one of claims 1 to 5 , further comprising a step of curing the resin layer in which the recess is formed. Manufacturing method. 7. The method of manufacturing a wiring structure according to claim 6, wherein the resin layer is cured by heating the resin layer to a predetermined temperature.
A method of manufacturing a wiring structure, which is characterized by the above. 8. The system of claim 1-7 method of manufacturing a wiring structure according to any one, the organic material was a polybenzoxazole as a substrate tree
A method for manufacturing a wiring structure, which is a resin, and the conductive film is removed by a chemical mechanical polishing method. 9. A photosensitive polyester having a positive photosensitivity on a substrate.
Forming the first resin layer using nzoxazole as a substrate
And a predetermined amount of ultraviolet light on a predetermined region of the first resin layer.
The opening that reaches the substrate surface by irradiating for a time
Forming a first latent image for forming on the first resin layer
And a step of developing the first latent image to form the opening in the first resin layer.
Of the first resin layer by heating to a predetermined temperature in air.
A step of erasing the property without curing treatment, and a positive photosensitive resin on the first resin layer including the opening.
The second by using a polybenzoxazole having the property of
A step of forming a resin layer, and a predetermined amount of ultraviolet rays are predetermined in a predetermined area of the second resin layer.
By irradiating for a time, it passes through the opening and moves in a predetermined direction.
A second groove for forming an extended groove in the second resin layer
And forming the second latent image to form the groove in the second resin layer.
Forming step, and the first and front portions in which the opening and the groove are formed
The second resin layer is heated and cured in an inert gas atmosphere.
And a step of conducting on the cured resin layer including the opening and the groove.
Forming a conductive film made of a conductive material, removing the conductive film from the surface, and opening the conductive film with the conductive material.
A process for forming a wiring structure in which the mouth and the groove are filled.
A method of manufacturing a wiring structure, comprising: