JP5625378B2 - Method for forming resin film pattern and method for manufacturing semiconductor device - Google Patents

Description

  The present invention relates to a resin film pattern forming method and a semiconductor device manufacturing method.

  Conventionally, polyimide-based and polybenzoxazole-based resins have been widely used for surface protection films and interlayer insulating films of semiconductor elements in terms of excellent heat resistance, electrical characteristics, mechanical characteristics, and film formation.

  As a positive photosensitive polyimide composition, a polyimide precursor in which an o-nitrobenzyl group is introduced by an ester bond, a composition containing a polyamic acid ester containing a phenolic hydroxyl group and an o-quinonediazide compound are known. When polyimide is used as a surface protective film or an interlayer insulating film, a process for forming a through hole or the like is mainly performed by an etching process using a photoresist.

  In addition, with the increase in functionality and performance of semiconductors, polybenzoxazole has been applied to semiconductors.

  Generally, the heat-resistant polymerizable composition for forming these resins is applied to a semiconductor element substrate such as a silicon wafer by spin coating using a spinner to form a uniform film. Thereafter, the excess solvent is conveyed to a hot plate for volatilization and drying (pre-baking).

In the step of drying the coating film, a wafer with a coating film (hereinafter also simply referred to as a wafer) is usually brought into close contact with a hot plate in a chamber and prebaked for a set time. Thereafter, the wafer is pushed up by pins, discharged from the chamber through a state of floating from the hot plate, and collected.
However, if the flow of the apparatus must be stopped due to an abnormality of the apparatus or replacement of a bottle for varnish, the wafer stagnates on the pins in the chamber after pre-baking. Due to this stagnation, the coating film was excessively dried, and there was a problem that the opening size after development was smaller than the design.

  An object of the present invention is to provide a method for forming a resin film pattern capable of suppressing over-drying of a coating film due to stagnation of a pin on a wafer after pre-baking and reduction of an opening size after development caused thereby.

According to the present invention, the following resin film pattern forming method and the like are provided.
1. (A) a coating process in which a photosensitive resin composition is coated on a wafer to form a coating film;
(B) a pre-baking step of drying the coating film on a hot plate;
(C) an exposure step of exposing the dried coating film, and
(D) includes a developing step for developing the exposed coating film in this order, and (b) the pre-baking step includes:
(B1) a step of holding the wafer having the coating film on a hot plate; and
(B2) A method of forming a resin film pattern including the steps of holding the wafer having the coating film in a state of being floated from a hot plate in this order.
2. (B1) The method for forming a resin film pattern according to 1, wherein the time of the step is set when the (b2) step is not performed, and is shorter than the optimum holding time on the hot plate.
3. (B1) The time of the process is 30 to 110 seconds and the temperature of the hot plate is 120 to 135 ° C. The (b2) time of the process is 30 to 110 seconds and the temperature of the hot plate is 120 to 135 ° C. Or the formation method of the resin film pattern of 2.
4). (B2) The method for forming a resin film pattern according to any one of 1 to 3, wherein in the step, the wafer is floated from the hot plate using pins.
5. The formation method of the resin film pattern in any one of 1-4 whose said photosensitive resin composition is a positive photosensitive resin composition containing a polyimide precursor or a polybenzoxazole precursor.
6). The size of the wafer is 5 to 10 inches, and the film thickness of the resin film pattern to be formed is (b2) the film thickness before exposure after the process is 8 to 12 μm. Forming method.
A resin film pattern is formed on the wafer by the method according to any one of 7.1 to 6, a semiconductor chip is obtained by cutting the wafer with the resin film pattern, and a semiconductor device is manufactured using the semiconductor chip Method.

  ADVANTAGE OF THE INVENTION According to this invention, the formation method of the resin film pattern which can suppress the excessive drying of the coating film by the pin top stagnation of the wafer after a prebaking, and the reduction | decrease of the opening dimension after image development caused by it can be provided.

  In addition, according to the present invention, a method for manufacturing a semiconductor device with high yield and high reliability can be provided.

(A) shows drying of the wafer on a hot plate, (b) is a schematic diagram which shows drying in the state which the wafer floated from the hot plate.

  Hereinafter, embodiments of a method for forming a resin film pattern and a method for manufacturing a semiconductor device according to the present invention will be described in detail. However, the present invention is not limited thereby.

The method of the present invention is a method for forming a resin film pattern on a wafer using a photosensitive resin composition, and includes the following steps (a) to (d) in this order.
(A) Application process for forming a coating film by applying a photosensitive resin composition on a wafer (b) Pre-baking process for drying the coating film on a hot plate (c) Exposure process for exposing the dried coating film (d) ) Development process to develop the exposed coating film

The step (b) includes the following steps (b1) and (b2) in this order.
(B1) The process of holding the wafer which has a coating film on a hot plate (b2) The process of holding the wafer which has a coating film in the state which floated from the hot plate

  Conventionally, all necessary drying is performed on a hot plate in the pre-bake process. Accordingly, when the wafer is lifted from the hot plate and moved to the next process, if the state of floating above the hot plate continues due to troubles or the like, it may become excessively dry and the opening size becomes too small, resulting in a defective product. However, in the present invention, in the pre-baking process, drying is divided into a pre-process (b1) and a post-process (b2). In the pre-process, the wafer is directly dried on the hot plate as usual, and then floated from the hot plate in the post process. dry. For example, the drying in the previous process may be less than the optimal drying, and this may be compensated by drying in the subsequent process. Alternatively, the drying in the previous process may be insufficient and the necessary minimum drying may be insufficient, and the drying process may exceed the necessary minimum in the subsequent process. Preferably, the pre-process and the post-process are combined to complete the optimal drying as in the conventional process. Even if a trouble or the like occurs during the post-process and the state continues, only the portion exceeding the preset dry time of the post-process is excessively dried, and the influence on the product is small.

  The reduction in yield due to conventional overdrying is a significant loss, especially when processing large wafers. Therefore, the present invention is particularly effective when a large wafer of about 5 to 12 inches is used.

  Although there is no restriction | limiting in particular as a photosensitive resin composition, The positive photosensitive resin composition containing at least 1 type of a polyimide precursor and a polybenzoxazole precursor can be used. The solvent is not particularly limited, and γ-butyrolactone (BLO), propylene glycol monomethyl ether acetate (PGMEA), N-methylpyrrolidone (NMP), toluene, xylene, tetrahydrofuran, alcohol and the like can be used.

  (A) In the coating process, for example, a photosensitive resin composition is dropped onto the upper surface of a rotating wafer (semiconductor element substrate) using a coating apparatus such as a spin coater. At this time, the dropped resin composition is spread evenly to the edge of the wafer by centrifugal force due to rotation. Thereby, a resin composition can be uniformly apply | coated on a wafer.

  The step (b) (steps (b1) and (b2)) can be performed by a heat drying apparatus equipped with a hot plate.

The drying conditions in the steps (b1) and (b2) can be adjusted as appropriate. For example, the drying temperature varies depending on the time, the type of composition component, and the like, and the drying time varies depending on the temperature, the type of composition component, and the like.
Usually, the hot plate temperature in the steps (b1) and (b2) is preferably 90 to 140 ° C, more preferably 110 to 140 ° C, further preferably 120 to 135 ° C, and most preferably 120 to 130 ° C.

  The time for the (b1) step can be set shorter than the optimum holding time on the hot plate that is set when the (b2) step is not performed. The time for the (b1) step can be, for example, 10 to 80% of the optimum holding time, more preferably 20 to 70%, and even more preferably 30 to 70%. Here, the optimum holding time is the same temperature as that set in step (b1) in the present invention, the pre-baking step is performed only in step (b1) without performing step (b2), and then in the present invention. When (c) the exposure process is performed under the same exposure conditions as those applied, and (d) the development process is performed under the same conditions as those applied in the present invention, the time during which the target pattern can be most satisfactorily formed. Say.

  The pre-bake time in the step (b1) is preferably set to 600 seconds or less, more preferably set to 110 seconds or less, and particularly preferably set to 70 seconds or less. On the other hand, it is preferably set to 10 seconds or more, and more preferably set to 30 seconds or more. (B2) The time of the step is preferably set to 10 seconds or more, more preferably set to 30 seconds or more. On the other hand, it is preferably set to 600 seconds or less, and more preferably set to 300 seconds or less. Preferably, it is more preferably set to 110 seconds or less.

  In the step (b2), as a means for bringing the wafer into a state of floating from the hot plate, a method of lifting with a pin is preferable. Usually, the wafer is lifted 1-10 cm above the hot plate.

  (B) The film thickness of the resin composition after a process becomes like this. Preferably it is 2-40 micrometers, More preferably, it is 5-20 micrometers.

  For the (c) exposure step and (d) development step, ordinary apparatuses and methods can be employed. For example, in the exposure step, the photosensitive resin composition formed into a film on the wafer can be irradiated with actinic rays such as ultraviolet rays, visible rays, and radiations through a mask. As the irradiation apparatus, various exposure apparatuses such as an i-line stepper that exposes 365 nm i-line monochromatic light can be used. In the development step, a pattern can be obtained by removing the exposed portion (in the case of using a positive photosensitive resin composition) with a developer. As the developer, for example, tetramethylammonium hydroxide (TMAH) An aqueous alkali solution such as is preferred, and the base concentration of the solution is usually 0.1 to 10% by weight.

  After the step (d), treatments such as rinsing, spin drying, post-development baking, etc. can be performed.

  A coating apparatus, a heating / drying apparatus, an exposure apparatus, and a developing apparatus used in each process may be separately installed, and the wafer may be transferred to another apparatus after the process of one apparatus is completed using a transfer unit. However, an apparatus configuration in which several apparatuses or all apparatuses are integrated may be employed.

  The semiconductor device manufacturing method of the present invention uses a semiconductor chip obtained by cutting a wafer obtained by the above method. Preferably, the resin film pattern obtained by the above method is used as the surface protective film and the interlayer insulating film.

  In the method for producing a resin film pattern of the present invention, when a resin composition film is formed on a substrate (wafer) in semiconductor element fabrication, a relief pattern excellent in appearance and coating film shape for a pattern of 5 μm or more is formed. be able to. Therefore, a highly reliable electronic component can be manufactured with a high yield.

Example 1
On a 6-inch silicon wafer, varnish HD-8000 (polyimide precursor, solvent BLO / PGMEA mixed solvent) (manufactured by Hitachi Chemical DuPont Microsystems) Spin was performed at 2030 rpm for 30 seconds. Next, this is pre-baked on a hot plate in the chamber at 130 ° C. for 60 seconds (FIG. 1A), and then the wafer is lifted with pins in the chamber, and the wafer is supported by the pins and floats off the hot plate. In this state (FIG. 1B), prebaking was further performed at 130 ° C. for 70 seconds (standby on the setting pin).
Note that the optimum holding time when the standby on the setting pin is not performed is 130 seconds.

  Continue to keep the wafer floating for 0, 90, or 180 seconds for the purpose of observing variations in the opening size due to the waiting time on the pins (effects of excessive drying due to the stop of the manufacturing flow due to troubles, etc.) The wafer was removed from the chamber.

Then, using FPA-3000iW manufactured by Canon, the coating film on the wafer was exposed to light having a wavelength of 365 nm with a design dimension of 5 μm at 210 mJ / cm ² .

  Next, using the coating and developing apparatus, the wafer was developed twice with 2.38% tetramethylammonium hydroxide (TMAH) (developer) while rotating the wafer at 50 rpm for 35 seconds. The wafer was rinsed with pure water for 15 seconds, spin-dried at 3500 rpm for 10 seconds, and baked after development at 140 ° C. for 180 seconds on a hot plate. Table 1 shows the formation conditions of the resin film pattern, the film thickness after pre-baking and after baking after development.

The film thickness of the produced polyimide film was measured by a large interference Lambda VM8000-LS / DNS manufactured by Dainippon Screen Manufacturing Co., Ltd., and it was confirmed that the film thickness was 6.7 to 7.0 μm.
Further, this polyimide film was observed with an Olympus digital metal microscope at a magnification of 100 times to obtain an opening dimension (CD). The results are shown in Table 2.

Example 2
In the same manner as in Example 1, varnish HD-8820 (polyimide precursor, solvent BLO / PGMEA mixed solvent) (manufactured by Hitachi Chemical DuPont Microsystems Co., Ltd.) was applied and spun. Thereafter, pre-baking was performed at 125 ° C. for 70 seconds on the hot plate in the chamber, and further, pre-baking was performed at 125 ° C. for 60 seconds (standby on the setting pins) in a state where the wafer was supported by the pins and floated from the hot plate.
Note that the optimum holding time when the standby on the setting pin is not performed is 130 seconds.

  For the purpose of observing the variation of the opening size due to the waiting time on the pin, the wafer is kept floating for 0, 100, 200 or 300 seconds (waiting on the trouble pin), and the wafer is taken out from the hot plate chamber. It was.

Exposure, development, rinsing, spin drying and post-development baking were performed in the same manner as in Example 1 except that the exposure amount was 230 mJ / cm ² and development was performed twice for 28 seconds with TMAH.

The film thickness of the produced polyimide film was measured by a large interference Lambda VM8000-LS / DNS manufactured by Dainippon Screen Manufacturing Co., Ltd., and it was confirmed that the film thickness was 6.7 to 7.0 μm.
The polyimide film was observed with an Olympus digital metal microscope at a magnification of 100 to obtain CD. The results are shown in Table 2.

Comparative Example 1
Varnish was applied in the same manner as in Example 1, and spin was performed at 1250 rpm for 30 seconds. Thereafter, pre-baking was performed in a chamber on a hot plate at 125 ° C. for 130 seconds.

  For the purpose of observing the variation of the opening dimension etc. due to the waiting time on the pins, the wafer is supported by the pins for 0, 90 or 180 seconds and kept floating from the hot plate (waiting on the trouble pins), then the wafer Was removed from the hot plate chamber.

Exposure, development, rinsing, spin drying, and post-development baking were performed in the same manner as in Example 1 except that the exposure amount was 320 mJ / cm ² and development was performed twice for 40 seconds with TMAH.

The film thickness of the prepared polyimide film was measured with a large interference lambda VM-8000 / LS / DNS manufactured by Dainippon Screen Manufacturing Co., Ltd., and it was confirmed that the film thickness was 9.9 to 10.2 μm.
The polyimide film was observed with an Olympus digital metal microscope at a magnification of 100 to obtain CD. The results are shown in Table 2.

Comparative Example 2
Varnish was applied in the same manner as in Example 1, and spin was performed at 2030 rpm for 30 seconds. Thereafter, pre-baking was performed in a chamber on a hot plate at 125 ° C. for 130 seconds.

  The wafer was supported by the pins and kept floating from the hot plate for 0, 100, 200, or 300 seconds for the purpose of observing variations in the opening size and the like due to the waiting time on the pins (waiting on the trouble pins). Later, the wafer was removed from the hot plate chamber.

Thereafter, exposure, development, rinsing, spin drying, and post-development baking were performed in the same manner as in Example 1 except that the exposure amount was 250 mJ / cm ² .

The film thickness of the produced polyimide film was measured by a large interference lambda VM-8000 / LS / DNS manufactured by Dainippon Screen Mfg. Co., Ltd. The film thickness was confirmed to be 6.9 to 7.1 μm.
The polyimide film was observed with an Olympus digital metal microscope at a magnification of 100 to obtain CD. The results are shown in Table 2.

Comparative Example 3
On a 6-inch silicon wafer, varnish HD-8000 (polyimide precursor, solvent BLO / PGMEA mixed solvent) (manufactured by Hitachi Chemical DuPont Microsystems) Spin was performed at 3500 rpm for 30 seconds. Thereafter, pre-baking was performed in a chamber on a hot plate at 120 ° C. for 130 seconds.

  For the purpose of observing the variation of the opening dimension etc. due to the waiting time on the pins, the wafer is supported by the pins for 0, 90 or 180 seconds and kept floating from the hot plate (waiting on the trouble pins), then the wafer Was removed from the hot plate chamber.

Thereafter, the wafer was exposed at 480 mJ / cm ^{2 with} light having a wavelength of 365 nm using Canon FPA-3000iW.

  Except for development twice with TMAH for 41 seconds, exposure, development, rinsing, spin drying and post-develop baking were performed in the same manner as in Example 1.

The film thickness of the produced polyimide film was measured by a large interference lambda VM-8000 / LS / DNS manufactured by Dainippon Screen Manufacturing Co., Ltd., and it was confirmed that the film thickness was 9.7 to 10.0 μm.
The polyimide film was observed with an Olympus digital metal microscope at a magnification of 100 to obtain CD. The results are shown in Table 2.

Comparative Example 4
On a 6-inch silicon wafer, varnish HD-8000 (polyimide precursor, solvent BLO / PGMEA mixed solvent) (manufactured by Hitachi Chemical DuPont Microsystems) Spin was performed at 3290 rpm for 30 seconds. Thereafter, pre-baking was performed in a chamber on a hot plate at 120 ° C. for 130 seconds.

  For the purpose of observing the variation of the opening size etc. due to the waiting time on the pin, the wafer is supported by the pin for 0 or 180 seconds and kept floating from the hot plate (waiting on the trouble pin). Removed from hot plate chamber.

Thereafter, the wafer was exposed to 350 mJ / cm ^{2 with} light having a wavelength of 365 nm using Canon FPA-3000iW.

  Except for development twice with TMAH for 35 seconds, exposure, development, rinsing, spin drying and post-develop baking were performed in the same manner as in Example 1.

The film thickness of the produced polyimide film was measured by a large interference lambda VM-8000 / LS / DNS manufactured by Dainippon Screen Manufacturing Co., Ltd., and the film thickness was confirmed to be 7.0 to 7.2 μm.
The polyimide film was observed with an Olympus digital metal microscope at a magnification of 100 to obtain CD. The results are shown in Table 2.

Comparative Example 5
On a 6-inch silicon wafer, varnish HD-8000 (polyimide precursor, solvent BLO / PGMEA mixed solvent) (manufactured by Hitachi Chemical DuPont Microsystems) Spin was performed at 2030 rpm for 30 seconds. Thereafter, pre-baking was performed in a chamber on a hot plate at 130 ° C. for 130 seconds.

  For the purpose of observing the variation of the opening dimension etc. due to the waiting time on the pins, the wafer is supported by the pins for 0, 90 or 180 seconds and kept floating from the hot plate (waiting on the trouble pins), then the wafer Was removed from the hot plate chamber.

Subsequently, the wafer was exposed to 210 mJ / cm ^{2 with} light having a wavelength of 365 nm using Canon FPA-3000iW.

Except for development twice with TMAH for 47 seconds, exposure, development, rinsing, spin drying and post-develop baking were performed in the same manner as in Example 1.

The film thickness of the produced polyimide film was measured by a large interference lambda VM-8000 / LS / DNS manufactured by Dainippon Screen Manufacturing Co., Ltd., and it was confirmed that the film thickness was 6.7 to 7.0 μm.
The polyimide film was observed with an Olympus digital metal microscope at a magnification of 100 to obtain CD. The results are shown in Table 2.

  As shown in Table 2, in the examples, the influence on the opening size due to excessive drying was small.

  The method for forming a resin film pattern of the present invention can be used for manufacturing electronic parts such as semiconductor elements.

Claims (7)

(A) a coating process in which a photosensitive resin composition is coated on a wafer to form a coating film;
(B) a pre-baking step of drying the coating film on a hot plate;
(C) an exposure step of exposing the dried coating film, and
(D) includes a developing step for developing the exposed coating film in this order, and (b) the pre-baking step includes:
(B1) a step of holding the wafer having the coating film on a hot plate; and
(B2) A method of forming a resin film pattern including, in this order, a step of holding the wafer having the coating film in a state of floating from a hot plate , wherein (b1) time of step (b2) is performed A resin film that is shorter than the optimum holding time on the hot plate, set in the case where there is not, (b1) the time of the step is 30 to 600 seconds, and (b2) the time of the step is 10 to 600 seconds Pattern formation method. The method of forming a resin film pattern according to claim 1, wherein the temperature of the hot plate in the step (b1) is 90 to 140 ° C, and the temperature of the hot plate in the step (b2) is 90 to 140 ° C.   The method for forming a resin film pattern according to claim 1 or 2, wherein the temperature of the hot plate in the step (b1) is 110 to 140 ° C, and the temperature of the hot plate in the step (b2) is 110 to 140 ° C.   The method for forming a resin film pattern according to any one of claims 1 to 3, wherein in the step (b2), the wafer is floated from the hot plate by using a pin.   The method for forming a resin film pattern according to claim 1, wherein the photosensitive resin composition is a positive photosensitive resin composition containing a polyimide precursor or a polybenzoxazole precursor. The resin film according to any one of claims 1 to 5, wherein the size of the wafer is 5 to 12 inches, and the film thickness of the resin film pattern to be formed is 8 to 12 µm in the film thickness before (b2) post-exposure exposure. Pattern formation method.   A resin film pattern is formed on a wafer by the method according to claim 1, the wafer with the resin film pattern is cut to obtain a semiconductor chip, and a semiconductor device is manufactured using the semiconductor chip. Method.