JP4208562B2 - Transfer method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to various substrates (hereinafter simply referred to as “substrates”) such as semiconductor wafers, photomask glass substrates, liquid crystal display glass substrates, plasma display glass substrates, optical disk substrates, etc. The present invention relates to a transfer method for transferring a transfer layer.
[0002]
[Prior art]
In recent years, with an increase in the diameter of a wafer used for manufacturing an LSI and an increase in the area of a liquid crystal panel or the like, a thin film forming method suitable for the large area has become necessary. In addition, in the field of multilayer wiring technology in LSI manufacturing technology, it is necessary to planarize the surface of the insulating film with high accuracy in order to realize multilayer wiring. In addition to increasing the area, planarizing the surface in thin film formation The demand for technology is also increasing. In order to satisfy these requirements, a transfer technique for forming a thin film on a substrate by a pressure transfer method using a sheet film has been proposed (see Patent Document 1).
[0003]
In the transfer method described in Patent Document 1, the substrate is placed on a sample stage so that the surface of a substrate such as a semiconductor wafer or a glass substrate for a liquid crystal panel faces upward. On the other hand, a sheet film having an insulating film (corresponding to the “transfer target layer” of the present invention) formed in advance on the surface thereof is mounted on a transfer plate disposed oppositely above the sample stage. Then, after moving the sample stage toward the transfer plate and bringing the substrate and the sheet film into contact with each other, a weight is applied to the substrate for a predetermined time and the substrate is heated to a predetermined temperature. By doing so, the sheet film and the substrate are brought into close contact with each other with the insulating film interposed therebetween. Thereafter, the insulating film is transferred to the substrate by peeling the sheet film.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-189565 (pages 4-5, FIG. 3)
[0005]
[Problems to be solved by the invention]
By the way, since the sheet film used in the transfer method described in Patent Document 1 has flexibility, misalignment between the insulating film formed in advance on the sheet film and the substrate occurs during the transfer process. The transfer dimensional accuracy has a certain limit. In recent years, there has been an increasing demand to transfer not only an insulating film as a layer to be transferred but also a layer having a predetermined circuit pattern to a substrate. However, in the prior art, satisfying such a request in terms of transfer accuracy It was virtually impossible.
[0006]
The present invention has been made in view of the above problems, and an object thereof is to provide a transfer method capable of transferring a transfer layer onto a substrate with high dimensional accuracy.
[0007]
[Means for Solving the Problems]
The present invention is a transfer method for transferring a transfer layer having a predetermined circuit pattern to a substrate, and in order to achieve the above object, at least one deposited layer including a release layer is formed of an inflexible plate-like substrate. A deposited layer forming step formed on the material, a transferred layer forming step for forming a transferred layer on the deposited layer formed on the substrate, and the transferred layer on the substrate by pressing the substrate and the substrate together A step of forming a through-plate having a through-hole corresponding to the circuit pattern; The step of storing the circuit material constituting the circuit pattern in the supply container with the plate as one side, the step of pressurizing the inside of the supply container to cue up the circuit material from the through hole, and the supply container and the base material relatively Close the circuit material cueed from the through hole. A step of contacting the deposited layer on the wood, and a step of forming the transferred layer by leaving the contact with the circuit material on the deposited layer.
[0008]
In the invention configured as described above, the transfer target layer is transferred to the substrate using an inflexible plate-like base material. That is, the base material and the substrate are pressed against each other, whereby the transfer layer formed on the plate-like base material is in close contact with the substrate. Then, the plate-like base material is selectively peeled by removing the release layer previously formed on the base material side, and the transferred layer is transferred from the plate-like base material to the substrate. By using an inflexible base material in this manner, the occurrence of misalignment between the transferred layer and the substrate can be suppressed, and the transferred layer can be transferred to the substrate with excellent dimensional accuracy.
[0009]
In addition, the peeling process can be stably performed as compared with the prior art, and the quality of the final product can be improved. That is, when a sheet film is used as in the conventional transfer method, for example, the transfer method described in Patent Document 1, the external force acting on the sheet film when peeled from the substrate is directly applied to the layer to be transferred in the peeling direction. As a result, the adhesion between the substrate and the transferred layer may be reduced. Further, it is difficult to maintain the external force uniformly, and the external force may act non-uniformly on the entire contact surface between the substrate and the layer to be transferred, leading to a decrease in transfer quality. On the other hand, in this invention, a peeling layer is formed in advance on the base material side, and by removing this peeling layer, the base material is selectively peeled from the substrate while the transfer layer is in close contact with the substrate. Therefore, the peeling process can be performed stably without impairing the adhesion between the transfer layer and the substrate.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a flowchart showing an embodiment of a transfer method according to the present invention. FIG. 2 is a flowchart showing a procedure for forming a fine pattern (circuit pattern). 3 and 4 are schematic views showing the transfer method of FIG. Hereinafter, this embodiment will be described in detail with reference to these drawings.
[0011]
In this embodiment, a quartz plate 1 is prepared as an “inflexible plate-like substrate” of the present invention, a release layer 2 is uniformly applied on the quartz plate 1, and a deposition layer 3 consisting of the release layer 2 alone. (Step S1; deposited layer forming step). The release layer 2 may be made of a material corresponding to a laser used in laser ablation described later. In this embodiment, (1) ablation with an excimer laser is performed.
(2) Since a part of the release material may adhere to the substrate during ablation, it is preferable to use a material that does not adversely affect the manufacturing process.
In response to the above, polyimide is used as a peeling material. Of course, the material constituting the release layer 2 is not limited to polyimide, and a material that satisfies the above two conditions can be used. In addition, about the formation method of the peeling layer 2, the apply | coating method conventionally used frequently, such as a spin coat method and a slit coat method, can be used.
[0012]
Then, a fine pattern as a transferred layer is formed on the release layer 2 formed on the quartz plate 1 (step S2; transferred layer forming step). Here, the case where a metal wiring pattern is formed as an example of the transferred layer forming step will be described in detail with reference to FIGS.
[0013]
First, the through plate 11 having the through holes 12 corresponding to the fine pattern is formed (step S21). As this penetration board 11, bases, such as a polyimide board and a silicon wafer, can be used, for example. Further, in order to prevent a pattern material or the like from adhering to the periphery of the through hole 12 during a cueing process or a pattern transfer process, which will be described later, water repellent is applied to at least the surface of the through plate 11 facing the quartz plate 1. It is desirable to perform processing.
[0014]
And as shown to Fig.3 (a), the pattern material (circuit substance) 14 which comprises a circuit pattern is stored in the supply container 13 which makes the penetration board 11 the whole surface (step S22). As the pattern material 14 for the metal wiring, for example, “Nano Paste” manufactured by Harima Kasei Co., Ltd. can be stored in the supply container 13. The storage of the pattern material 14 may be automatically supplied from a circuit substance supply source (not shown) to the supply container 13 or may be performed manually by an operator. In addition, only by supplying the pattern material 14 to the supply container 13, the pattern material 14 from the through hole 12 depends on the relationship between the wall surface of the through hole 12 and the surface tension of the gas-liquid interface of the pattern material 14 located in the through hole 12. Will not leak. Further, when a predetermined amount of pattern material 14 is stored inside the supply container 13, the internal space 15 of the supply container 13 is a sealed space, and the atmospheric pressure thereof is substantially the same as the atmospheric pressure around the supply container 13. Further, prior to storing the pattern material 14, the quartz plate 1 aligned at a position facing the through plate 11 is vacuum-adsorbed on the upper surface of the planarizing stage 16 without bending.
[0015]
In the next step S23, a predetermined pressure is applied to the internal space 15 of the supply container 13 to cue the pattern material 14 as shown in FIG. That is, by supplying nitrogen gas to the space 15 in the supply container 13, the space 15 is set to a preset cueing pressure that is equal to or higher than the atmospheric pressure around the supply container 13. At this time, it is desirable to control so that the space 15 is always maintained at a constant cueing pressure based on the measurement result by the barometer. This “cue pressure” is a pressure at which the pattern material 14 can be cueed from the through hole 12, and various parameters such as the viscosity and surface tension of the pattern material 14, the aspect ratio of the through hole 12, and the material of the through plate 11. The optimum value is determined by. Therefore, it is preferable to obtain an optimum value of the cueing pressure in advance by experiment and set the value.
[0016]
Here, “cueing” is a phenomenon in which the pressurized pattern material 14 swells below the through plate 11 through the through hole 12. Further, in this embodiment, the space 15 in the supply container 13 is maintained at the cueing pressure, whereby the pattern material 14 is gradually pushed out of the through hole 12 and eventually the cueing portion 17 is formed below the through hole 12. Form. In addition, since surface tension acts on the cueing portion 17, when the cueing portion 17 has a certain size or less, it does not drop downward. Further, the size and shape of the cueing portion 17 are detected as necessary, and the cueing pressure is adjusted by adjusting the amount of nitrogen gas fed into the space 15 in the supply container 13 based on the detection result. The cueing unit 17 may be controlled.
[0017]
Next, the inside of the supply container 13 is adjusted to a predetermined transfer pressure by a pressure adjusting mechanism (not shown). More specifically, the space 15 in the supply container 13 is set to a transfer pressure lower than the cueing pressure, and the holding of the through plate 11 is reduced by the pressure reduction in this way, as shown in FIG. As shown, the through-hole plate 11 is in a substantially flat state.
[0018]
Then, in this state, the flattening stage 16 is raised to the transfer position, and as shown in FIG. 4C, the peeling layer 2 formed on the quartz plate 1 with the through plate 11 and the quartz plate 1 being close to each other. And the cueing portion 17 are brought into contact with each other (step S24). Here, the transfer position is a position for transferring the pattern material 14 to the quartz plate 1, and is a position where the quartz plate 1 contacts the cueing portion 17 and does not contact the penetrating plate 11. The reason why the quartz plate 1 is not brought into contact with the through plate 11 is that the contaminants adhering to the through plate 11 are not transferred to the quartz plate 1.
[0019]
When the contact of the cueing portion 17 with the quartz plate 1 is completed in this way, the flattening stage 16 is lowered again to the original standby position as shown in FIG. Separate. As a result, the cueing portion 17 contacted in step S24 adheres to the quartz plate 1 and the fine pattern 18 is transferred (step S25). At this time, if the penetrating plate 11 and the quartz plate 1 are rapidly separated, the separation (residual) of the pattern material 14 does not satisfy the same condition and a transfer may be defective. It is necessary to lower the flattening stage 16 at a slower speed.
[0020]
When the layer having the fine pattern 18, that is, the layer to be transferred of the present invention is formed by non-contact transfer as described above, the process proceeds to step S3 in FIG. Returning to FIG. 1, the description will be continued with reference to FIGS. 1 and 4.
[0021]
In this step S3, as shown in FIG. 4A, the quartz plate 1 in which the fine pattern 18 is formed on the release layer 2 and the substrate W to which the fine pattern 18 is to be transferred are transported to the processing chamber, The quartz plate 1 and the substrate W are aligned so that the fine pattern 18 faces the transfer position of the substrate W in the processing chamber. Then, while reducing the pressure in the processing chamber, the quartz plate 1 and the substrate W are controlled to be heated, and when a predetermined transfer condition is reached, the substrate W is moved in a direction close to the quartz plate 1 to thereby transfer the fine pattern 18 to the substrate W. (Step S4; adhesion process). As a result, an adhesion object in which the substrate W and the quartz plate 1 are integrated with each other through the fine pattern 18 is formed.
[0022]
Here, in this embodiment, the fine pattern (transfer target layer) 18 on the peeling layer 2 of the quartz plate 1 is brought into close contact with the substrate W by moving the substrate W, but the quartz plate 1 is close to the substrate W. The contact processing may be performed by moving the substrate W and the quartz plate 1 to the other side. In short, at least one of the substrate W and the quartz plate 1 is moved to the other side. Thus, the fine pattern (transfer target layer) 18 may be configured to be in close contact with the substrate W.
[0023]
In the next step S5, the peeling layer 2 is selectively removed by laser ablation, and only the quartz plate 1 is separated from the substrate W while the fine pattern 18 is kept in close contact with the substrate W to complete the transfer of the fine pattern 18. (Peeling process). This laser ablation is a phenomenon in which a target layer is irradiated with laser light to explosively evaporate a substance constituting the target layer and scatter as gaseous particles. The release layer 2 is removed using laser ablation. That is, as shown in FIGS. 4B and 4D, the excimer laser L is emitted toward the back surface of the quartz plate 1 (the main surface on which the release layer 2 and the fine pattern 18 are not formed). The laser L passes through the quartz plate 1 and is applied to the release layer 2. Then, the portion (a shaded portion in FIG. 4D) 2a that has received the laser L is removed by laser ablation. Since it is currently impossible to irradiate high-energy excimer laser L simultaneously over a wide range, in this embodiment, excimer laser L is applied to release layer 2 as indicated by arrow P in FIG. On the other hand, the whole peeling layer 2 is removed by scanning while partially irradiating.
[0024]
In this embodiment, in parallel with the laser ablation process, the quartz plate 1 is peeled off as indicated by the symbol Q in FIG. More specifically, corresponding to the first irradiation of the excimer laser L to the region 2a, the peripheral edge portion 1a of the quartz plate 1 that coincides with the region 2a is relatively separated from the substrate W, and further, In accordance with the scanning of the laser beam L, the separation area between the quartz plate 1 and the substrate W is expanded from the separation start position 1a to the entire quartz plate 1. In order to relatively separate the quartz plate 1 and the substrate W, the substrate W may be moved instead of the quartz plate 1 or both may be moved away from each other.
[0025]
As described above, in this embodiment, the separation process is started by matching the irradiation start region (position) 2a of the laser L with the separation start position 1a, and the enlargement of the separation region is associated with the laser scanning. Further, by expanding the distance H between the quartz plate 1 and the substrate W corresponding to the laser ablation, the gaseous particles generated by the laser ablation are scattered from between the quartz plate 1 and the substrate W so that the gaseous particles are transferred to the substrate. Adhering to W or the quartz plate 1 can be suppressed. In addition, by widening the interval H, the replacement of the gaseous particles with the surrounding gas of the substrate W is promoted, so that the separation treatment of the quartz plate 1 can be performed smoothly and satisfactorily.
[0026]
When the removal of all the peeling layers 2 is completed, the quartz plate 1 is completely peeled off from the substrate W, while the fine pattern 18 remains on the substrate W as shown in FIG. Processing is complete. At this stage, since the metal particles as the wiring material are dispersed in the nano paste constituting the fine pattern 18, a thermal laser such as a YAG laser (yttrium / aluminum / garnet / laser) or a carbon dioxide laser is used as a substrate. By scanning W, the fine pattern 18 on the substrate W is melt-bonded to exhibit a function as wiring (step S6; melt-bonding step).
[0027]
As described above, according to this embodiment, the quartz pattern 1 and the substrate W are pressed against each other so that the fine pattern 18 that is the transfer layer formed on the release layer 2 of the quartz plate 1 is brought into close contact with the substrate W. Yes. By using the inflexible quartz plate 1 in this way, it is possible to effectively suppress the positional deviation between the fine pattern 18 and the substrate W during the adhesion process. In particular, when the fine pattern 18 is transferred to the substrate W, more precise alignment is required than when the thin film is transferred to the substrate W. In the transfer method described in Patent Document 1, the transfer of the fine pattern is performed. While this is practically impossible, using this embodiment makes such a transfer possible for the first time and is a useful transfer technique.
[0028]
Moreover, according to this embodiment, the peeling process can be performed stably, and the quality of the final product can be improved. That is, when the sheet film is peeled off from the substrate without using the release layer as in the transfer method described in Patent Document 1, the external force acting on the sheet film at the time of peeling from the substrate W is directly applied to the layer to be transferred. The contact force between the substrate and the transferred layer is reduced, and it is difficult to maintain the external force uniform, and the contact force between the substrate and the transferred layer is not uniform. End up. On the other hand, in this embodiment, the release layer 2 is formed in advance on the quartz plate 1 and the release layer 2 is removed by laser ablation, and a large external force is applied to the fine pattern 18 on the substrate W. In addition, the quartz plate 1 can be selectively peeled from the substrate W. Therefore, the peeling process can be stably performed without impairing the adhesion between the fine pattern 18 and the substrate W.
[0029]
The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above embodiment, the quartz plate 1 is used as the “inflexible plate-like substrate” of the present invention in order to remove the release layer 2 by laser ablation, but it has transparency to the excimer laser. May be adopted.
[0030]
Further, in the above embodiment, the “deposition layer” of the present invention is formed only by the release layer 2, but in addition to the release layer 2, other layers are stacked to form a deposition layer by a plurality of layers. Also good.
[0031]
In the above embodiment, the layer having the fine pattern 18 is used as the “transfer target layer” of the present invention. However, as described in Patent Document 1, the present invention is also applied to the case where the thin film is used as the “transfer target layer”. Can be applied. That is, the present invention can be applied to all transfer methods for transferring a wiring layer, an interlayer insulating layer, and the like to a substrate.
[0032]
In the above embodiment, the non-contact transfer method using the through-hole plate 11 is used to form the fine pattern 18. However, the non-contact transfer method is used for a method of forming a circuit pattern such as the fine pattern 18. Other than that, for example, a photoengraving method that has been frequently used in the semiconductor manufacturing process or the like can be used.
[0033]
Further, in the above-described embodiment, the release layer 2 is constituted by polyimide and the release layer 2 is ablated by the excimer laser L. However, the combination of the release material and the laser constituting the release layer 2 is limited to this. What is necessary is just to select suitably the thing corresponding to the process of a product, the material which comprises a to-be-transferred layer, etc. instead of a thing. Further, the peeling layer may be selectively removed by a method other than laser ablation.
[0034]
【The invention's effect】
As described above, according to the present invention, a release layer is formed in advance on an inflexible plate-like base material, the base material and the substrate are pressed against each other, and the transferred layer is adhered to the substrate, and then the release layer is formed. Since the base material is peeled off from the substrate, it is possible to suppress the occurrence of misalignment between the transferred layer and the substrate, and the transferred layer is transferred to the substrate with excellent dimensional accuracy. be able to. Moreover, since the base material is peeled from the substrate by removing the peeling layer, the peeling treatment can be stably performed without impairing the adhesion between the transferred layer and the substrate.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an embodiment of a transfer method according to the present invention.
FIG. 2 is a flowchart showing a procedure for forming a fine pattern (circuit pattern).
FIG. 3 is a schematic diagram illustrating the transfer method of FIG. 1;
4 is a schematic diagram showing the transfer method of FIG. 1; FIG.
[Explanation of symbols]
1 ... Quartz plate (base material)
1a ... peripheral edge (separation start position)
2 ... peeling layer 2a ... irradiation start position 3 ... deposition layer 11 ... through plate 12 ... through hole 13 ... supply container 14 ... pattern material (circuit substance)
18 ... fine pattern (circuit pattern, transferred layer)
L ... Excimer laser W ... Substrate

Claims (10)

A transfer method for transferring a transfer layer having a predetermined circuit pattern to a substrate,
A deposited layer forming step of forming at least one deposited layer including a release layer on an inflexible plate-like substrate;
A transferred layer forming step of forming the transferred layer on the deposited layer formed on the substrate;
An adhesion step in which the substrate and the substrate are pressed against each other to bring the transferred layer into close contact with the substrate;
A peeling step of removing the release layer and peeling the base material from the substrate ,
The transferred layer forming step includes
Forming a through plate having a through hole corresponding to the circuit pattern;
Storing the circuit material constituting the circuit pattern in a supply container having the through plate as one surface;
Pressurizing the inside of the supply container to cue the circuit material from the through hole;
Bringing the supply container and the base material relatively close to each other, and bringing the circuit material cueed from the through hole into contact with the deposited layer on the base material;
Forming the transferred layer by leaving the contacted circuit material on the deposited layer; and
Transfer method and having a.   The transfer method according to claim 1, wherein the deposited layer is composed of only the release layer. The peeling after step transfer method according to claim 1, wherein further comprising a fusion bonding step of melt bonding the circuit pattern. The adhesion step is transferring method according to any of claims 1 to 3 after the alignment of the substrate and the substrate is pressed against each other and the substrate and the substrate. The peeling step is transferring method according to any of claims 1 to 4 by laser ablation effect removal of the release layer. In the peeling step, a part of a peripheral edge of the base material is relatively separated from the substrate as a separation start position, and a separation region between the base material and the substrate is moved from the separation start position to the base. The transfer method according to claim 5 , wherein the transfer method is spread over the entire material. The transfer method according to claim 6 , wherein laser ablation is performed by scanning while irradiating the release layer with laser.
The peeling step is a transfer method in which a peeling process is started by matching a laser irradiation start position with the separation start position. The transfer method according to claim 7 , wherein the peeling step scans the laser in response to enlarging the separation area. The substrate is transparent to the laser used for laser ablation;
The peeling step is transferring method according to any of claims 5 to 8 is irradiated with the laser to the peeling layer through the substrate. Transfer method according to any one of the substrate claims 1 a quartz plate 9.

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