JPH09320913A - Wafer joining method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To join a wafer to a substrate with good efficiency inside a vacuum chamber. SOLUTION: In this method, a substrate 9 and a wafer 6, wherein adhesives 7, 8 are applied to one side of at least either of the substrate 9 and the wafer 9 are joined together on the surface whereto the adhesive is applied. In this case, the substrate 9 and the wafer 6, whose joining faces are in the separate state, are mounted on the material holding means 14 inside a vacuum chamber 3. Next, the substrate 9 an the wafer 6 are transferred on a heating means 10 being arranged inside the vacuum chamber and holding the joining temperature so as to form a joined object 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer sticking method used in a thin wafer manufacturing process in a semiconductor device manufacturing process before a high precision thin wafer is manufactured, and an apparatus used therefor. Is.

[0002]

2. Description of the Related Art When polishing a semiconductor wafer, in order to prevent the semiconductor wafer from cracking, the semiconductor wafer is attached to a glass plate with an adhesive and then polished.
However, air may be trapped between the semiconductor wafer and the glass plate to leave bubbles. In this case, at the place where bubbles exist, the semiconductor wafer may be recessed inward during polishing, and only that portion may be deformed or cracked as an origin. Therefore, a method of attaching in vacuum has been developed as a method of preventing bubbles. This method is illustrated in FIG.
This will be described below with reference to FIG.

FIG. 2 is a sectional view of a conventional wafer sticking apparatus used for sticking a wafer in a vacuum.

In the figure, 1 is a cylinder, 2 is a vacuum exhaust port, 3 is a vacuum chamber, 4 is a pressure plate, 5 is a rubber plate, 6 is a semiconductor wafer, 7 is a second negative resist, and 8 is a first negative resist. , 9 is a glass plate, 10 is a hot plate, 11 is a tilt adjusting screw, 12 is a heater, and 13 is the second negative resist 7 coated surface of the semiconductor wafer 6 and the first negative resist 8 coated surface of the glass plate 9 are attached. It is a pasting thing.

The structure of this device will be described below. The cylinder 1 is vertically movable and is attached to a vacuum chamber 3 in a state where a vacuum is held by an O-ring 1a, and a circular pressure plate 4 is attached to the lower end inside the vacuum chamber 3. Further, on the back surface of the pressure plate 4, a rubber plate 5 is attached, the center of which protrudes downwardly downwardly and which has a gentle slope downward toward the peripheral edge. Below the rubber plate 5 is a heater 1 for heating whose upper surface is made horizontal by an inclination adjusting screw 11.
A hot plate 10 incorporating 2 is disposed in the chamber 3. Further, a vacuum exhaust port 2 connected to a vacuum pump (not shown) for exhausting the inside of the vacuum chamber 3 is provided.

The method of using this device will be described below. Outside the vacuum chamber 3, the semiconductor wafer 6 is coated with the second negative resist 7 and the glass plate 9 is covered with the first negative resist 8.
The surfaces coated with are superposed to form a superposed product 13a. At this time, the volatile components in the negative resists 7 and 8 are evaporated so that the negative resists 7 and 8 are not foamed by the subsequent vacuum evacuation, and then the negative resists 7 and 8 are superposed. Next, the vacuum chamber 3
The glass plate 9 is placed on the inner hot plate 10 so that the center of the semiconductor wafer 6 is directly below the center of the pressure plate 4. Subsequently, the inside of the vacuum chamber 3 is evacuated by exhausting from the vacuum exhaust port 2 with a vacuum pump (not shown). At this time, the air between the first negative resist 8 and the second negative resist 7 is also exhausted.

Next, the heater 1 of the hot plate 10
2 is energized to raise the temperature, and the stack 13a of the semiconductor wafer 6 and the glass plate 9 is controlled to a predetermined temperature and kept at that temperature for a predetermined time. Subsequently, while keeping the pressure plate 4 horizontal, the cylinder 1 is lowered to press the center of the semiconductor wafer 6 at the center of the rubber plate 5, and further lowered to apply pressure from the center of the semiconductor wafer 6 to the outside. Pressurize the entire surface while expanding the pressure surface. By this,
The first negative resist 8 and the second negative resist 7 are adhered while ejecting bubbles and the like remaining on the adhered surfaces to form the adherend 13. Subsequently, the cylinder 1 is raised and the vacuum is broken, and the adhered object 13 of the semiconductor wafer 6 and the glass plate 9 is taken out. Here, the superposed product 13a is only superposed on the adhesive coated surface, and the pasted product 13 heats or pressurizes the superposed product 13a so that the semiconductor wafer 6 and the glass plate 9 are exposed to the photoresist 7, It means pasted in 8.

Subsequently, the pasting object 13 is supplied to the next step of polishing the semiconductor wafer 6.

[0009]

In the wafer bonding apparatus having the above-mentioned structure, it is necessary to break the vacuum and load and unload the sample every time when a pair of the substrate and the wafer are bonded, and the air between the adhesives is removed. Since the vacuum was removed as much as possible and the superposed products were heated and brought into close contact with each other, it took time to reach a predetermined temperature, resulting in poor work efficiency. In addition, air bubbles may remain between the adhesives or between the adhesives and the substrate or the wafer in order to make a vacuum after the adhesives are superposed. When air bubbles cannot be completely removed by pressurization,
It was impossible to completely prevent the bubble portion from being deformed in the subsequent polishing step and becoming the origin of the crack, and the wafer from being broken.

[0010]

The present invention has been proposed in order to solve the above-mentioned problems, and a substrate and a wafer in which an adhesive is applied to at least one surface of a substrate and a wafer are attached by an adhesive-applied surface. A method of placing the substrate and the wafer on the material storage means in the evacuated vacuum chamber with the bonding surfaces separated from each other, and on the heating means arranged in the vacuum chamber and brought to the bonding temperature. Provided is a wafer bonding method including a step of transferring a substrate and a wafer to form a bonded object. In this way, since the transfer is carried out on the heating means set to the sticking temperature and the sticking is carried out, the heating means is not heated and cooled one by one, so that the working efficiency is improved. Further, since the substrates and the wafer are placed in the vacuum chamber with the bonding surfaces thereof separated from each other, air bubbles are not bitten between the wafers.

In addition to the above-mentioned method, the step of placing in the material storage means places a plurality of substrates and wafers, respectively, and the step of forming an adherent attaches the substrate and wafer one by one, and the heating means. Provided is a wafer bonding method which has a step of taking an adhered material from above and placing it on an adhered material storage means in a vacuum chamber and sequentially forming the adhered material. In this way, since multiple substrates and wafers are placed in the vacuum chamber and the adhesive is taken out from the heating means, the vacuum is broken after the multiple adhesives are formed. It will be even more efficient.

In addition to the above method, a step of transferring a vacuum chamber to a material storage means via a sub-vacuum chamber capable of evacuating a substrate and a wafer from the atmosphere, and a step of storing an attached material. And a step of taking out the vacuum chamber from the means to the atmosphere while maintaining the vacuum in the sub-vacuum chamber. In this way, without breaking the vacuum in the vacuum chamber,
Since the substrate and the wafer are supplied from the atmosphere and the adhered material is taken out into the atmosphere, the adhered material can be continuously formed, so that the working efficiency is further improved.

In addition to the above method, there is provided a wafer sticking method for performing a step of forming a sticking object after preheating during the step of placing the substrate and the wafer on the material storage means. In this way, since the paste is applied on the heating means that is maintained at the sticking temperature after the preheating, it is sufficiently degassed and does not foam due to the heating during the sticking, and the time on the heating means can be shortened. , Work efficiency is improved.

In addition to the above method, there is provided a wafer sticking method for pressing the sticking object on the heating means. In this way, by applying pressure when applying on the heating means, the applying time can be shortened and the working efficiency is improved.

In addition to the above method, there is provided a wafer bonding method in which the adhesive is photoresist. In this way, when a photoresist is used as the adhesive, it can be applied thinly and uniformly, so that air does not bite on the sticking surface, and the surface of the substrate and the surface of the wafer are parallel to each other, which is deformed during polishing, The origin of the crack does not occur, so it will not crack.

[0016] A device for applying an adhesive to at least one of the substrate and the wafer and attaching the substrate and the wafer with the adhesive-applied surface, wherein the attachment surfaces of the substrate and the wafer are separated by vacuum. Material storage means to be placed inside, heating means to heat to the bonding temperature, bonding means to transfer the substrate and wafer from the material storage means onto the heating means to form a bonded object, and house them inside And a vacuum chamber for operating the wafer. According to this device, the material can be degassed sufficiently in vacuum on the storage means and transferred to the heating means kept at the sticking temperature to form the sticking object. Efficiency is improved. In addition, since the substrate and the bonding surface of the wafer are separated from each other in a vacuum state, bubbles are not bitten between the wafers.

In addition to the above-mentioned apparatus, the material storage means is capable of mounting a plurality of substrates and wafers, respectively, and the adhered material storage means for mounting a plurality of adhered materials is disposed in the vacuum chamber and bonded. There is provided a wafer sticking device in which the means has a function of taking out the sticking material on the heating means to the sticking material storage means, or a dedicated taking-out means is arranged in the vacuum chamber. In this way, a plurality of substrates and wafers can be placed respectively, and since it is possible to transfer the pasted matter from the heating means to the pasted matter storage means,
Since multiple adhesives are formed until the vacuum is broken,
Work efficiency is further improved.

In addition to the above apparatus, a sub-vacuum chamber that can be evacuated and a material transfer that transfers a substrate and a wafer from the atmosphere to the material storage means via the sub-vacuum chamber while the vacuum chamber is held in vacuum And a bonding material transfer means for transferring the bonding material from the bonding material storage means to the atmosphere via the sub-vacuum chamber in the atmosphere while holding the vacuum chamber in a vacuum. Provide a device. Thus, without breaking the vacuum of the vacuum chamber, the substrate and the wafer were supplied from the atmosphere and the adhered material was taken out into the atmosphere, so that the adhered material could be formed continuously and the working efficiency was further improved. Get better.

In addition to the above-mentioned apparatus, there is provided a wafer sticking apparatus provided with a pressurizing means for pressurizing the sticking object placed on the heating means. Since the pressurizing means is disposed on the heating means in this way, the application time is shortened by the pressurization and the working efficiency is improved.

In addition to the above apparatus, there is provided a wafer sticking apparatus in which the material storage means includes a preheating means. In this way, since the material storage means is the preheating means, the temperature of the substrate or wafer supplied onto the heating means has already risen. Therefore, the bonding time on the heating means is shortened and the working efficiency is improved.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described with reference to the sectional view of the wafer bonding apparatus shown in FIG. However, the same parts as those in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted.

In the figure, 14 is a preheating plate which also serves as a material storage means and preheating means, 15 is a push-up pin, and 16 is a robot which is a pasting means.

The structure of the present invention will be described below. The structure added to the conventional device (FIG. 2) will be mainly described. A semiconductor wafer 6 and a glass plate 9 as a substrate are placed near a hot plate 10 which is a heating means, and a preheating plate 14 for preheating is arranged. This preheating means is also a material storage means here. The preheating plate 14 has push-up pins 15 for pushing up the semiconductor wafer 6 and the glass plate 9 on the preheating plate 14 from below.
Are arranged. Similarly, the hot plate 10 is also provided with a push-up pin 15 that pushes up the attachment 13 on the hot plate 10. In addition, a robot 16 having an arm 16a that can move and rotate in the X, Y, and Z directions near the hot plate 10 and the preheating plate 14.
Are arranged.

The preheating plate 14 is for mounting and heating a plurality of sets of semiconductor wafers 6 and glass plates 9 at the same time. The preheating means only stores a plurality of materials, and the preheating means is a heating plate or infrared rays. A heater may be used to heat the semiconductor wafer 6 and the glass plate 9 one by one from above or below. Alternatively, the plurality of wafers may be stored in a jig such as a wafer stand and heated. The heating means is the heater 1
The heating plate is not limited to the hot plate 10 by 2, and the heating plate may be heated from below by an infrared heater. The push-up pin 15 has only to lift at least one side or the whole of the semiconductor wafer 6, the glass plate 9, and the attachment 13. Further, instead of pushing up, the semiconductor wafer 6, the glass plate 9 and the attachment 13 may be moved to the end portions of the preheating plate 14 and the hot plate 10. The arms 16a of the robot 16 may be put under them and moved by scooping, or those objects may be sandwiched and lifted by the arms 16a.

The method of using this device will be described below. A plurality of wafers, for example, semiconductor wafers 6 coated with an adhesive agent such as the second negative resist 7 on the surface not to be polished, face up the second negative resist 7, and push up pins 15 on the preheating plate 14 held at a predetermined temperature. Place it in a position that can be lifted horizontally with. The predetermined temperature is the negative resist 7,
The temperature may be any temperature at which the adhesive can be efficiently attached without deteriorating the property of 8 and losing its function as an adhesive. In addition, the semiconductor wafer 6 whose one surface is coated with an adhesive such as the first negative resist 8
A plurality of substrates, which are at least as large as or larger than the semiconductor wafer 6, are placed on the preheating plate 14 at positions where they can be horizontally lifted by the push-up pins 15 with the first negative resist 8 facing upward. Place.
The substrate is not limited to the glass plate 9 and may have any flat surface and can be attached with an adhesive. Therefore, heat-resistant plastic, ceramic, or metal plate may be used. At this time, the preheating plate 14 for the semiconductor wafer 6 and the preheating plate 14 of the glass plate 9 may be different, or the preheating temperature may be different. Although not shown, a plurality of semiconductor wafers 6 and glass plates 9 are placed at different locations in the vacuum chamber 3, and one by one, not shown, is replenished on the preheating plate 14 by the transfer means or the robot 16. You may. The first negative resist 8 and the second negative resist 7 may be the same negative resist, or the negative resists 7 and 8 may be applied to only one of the semiconductor wafer 6 and the glass plate 9. Further, the semiconductor wafer 6 coated with the negative resists 7 and 8 and the glass plate 9 may be heated in a nitrogen atmosphere before being placed in the vacuum chamber 3 to evaporate the organic solvent in the negative resists 7 and 8. The pressure-sensitive adhesive may be thin and evenly applied, and may have an adhesive force that can withstand polishing by heating, and may be a positive resist, wax or the like. The use of a negative photoresist does not cause peeling due to light even when working in a bright place, and it is easy to apply it thinly and uniformly and horizontally.

Subsequently, the air in the vacuum chamber 3 is exhausted to a vacuum by exhaust means (not shown) connected to the vacuum exhaust port 2 and left for a predetermined time. The purpose of leaving it in vacuum is to degas from the negative resists 7 and 8, and it is effective even if it takes a long time even at room temperature, but here, the time is shortened by heating to a predetermined temperature.

Next, the first on the preheating plate 14
Push up the glass plate 9 coated with the negative resist 8 and push the pin 1
5 is pushed up and the sticking means, for example, the arm 16a of the robot 16 is inserted into the space between the preheating plate 14 and the glass plate 9, and the glass plate 9 is sandwiched between the center of the rubber plate 5 on the hot plate 10 controlled to a predetermined temperature. The glass plate 9 is transferred so that the center of the glass plate 9 is directly below. Similarly, the semiconductor wafer 6 is sandwiched by the robot 16 with the arm 16a reversed and transferred, and the negative resists 7 and 8 are superposed to form the superposed object 13a. Since the pre-heating is performed, the superposed product 13a is quickly heated to the negative resist 7, 8 because it is transferred onto the hot plate 10 which has already been heated.
Softens.

Subsequently, when the pasted object 13 placed on the hot plate 10 reaches a constant temperature, the cylinder 1 is lowered to press the substantially center of the semiconductor wafer 6 at the center of the rubber plate 5, and gradually the rubber plate 5 is gradually pressed. Is lowered and pressure is applied from the center to the outer peripheral direction to press the entire surface of the semiconductor wafer 6 with the rubber plate 5. By this pressurization, the sticky substance is firmly attached, and furthermore, it can be attached in a short time. Further, even if the semiconductor wafer 6 is warped, it can be attached horizontally by pressure.
However, in this case, it is necessary to stop the pressurization after the pressure-sensitive adhesive is solidified and does not warp even when the pressurization is removed. Also, it can be pasted in a short time. Preheating is not always necessary if the heat capacity of the pasted product is small or the heating temperature is low and the pasting is possible. The pasted object 13 may be formed by sticking the glass plate 9 on top. Subsequently, the rubber plate 5 is raised by the cylinder 1. If the adhesive strength of the pressure-sensitive adhesive is sufficient, it is not always necessary to apply pressure.

Subsequently, the sticking object 13 is pushed up by the push-up pin 15, and the arm 16a of the robot 16 is inserted between the hot plate 10 and the sticking object 13 and taken out. Place it in a designated place that is a means for storing the pasted matter. The pasted material storage means may be a shelf, a wafer stand, or stacked wafers, but the negative resist may be solidified on a cooling plate that is water-cooled. This robot 16
As a take-out means different from the pasting means, a dedicated robot may be installed in the vacuum chamber 3 and used.

By repeating the above operation, a plurality of the adhered objects 13 are continuously manufactured without breaking the vacuum of the vacuum chamber 3. After one of the semiconductor wafer 6 and the glass plate 9 that have not been stuck in the vacuum chamber 3 is exhausted, the vacuum is broken and the stuck object 13 is taken out. Generally, the same number of semiconductor wafers 6 and glass plates 9 are placed on the preheating heater 14.

Photoresist 7 on each side of a plurality of sheets,
The semiconductor wafer 6 coated with 8 and the glass plate 9 are placed in the vacuum chamber 3 at a time, and the vacuum is not broken until a plurality of adherends 13 are formed, so that the attachment can be performed efficiently. Further, since the adhesive is applied after the vacuum is applied, air is not trapped between the adhesives, so that there is no peeling between the adhesives or cracking of the wafer in the subsequent polishing step.

A substrate and a wafer can be inserted from the atmosphere,
In addition, the first sub-vacuum chamber that can be evacuated can be attached so that the substrate and the wafer can be inserted while the vacuum chamber is held in vacuum, and the attachment can be taken out from the vacuum chamber while the vacuum chamber is held in vacuum. Two sub-vacuum chambers may be attached. At this time, a material transfer means for transferring the semiconductor wafer and the glass plate from the first sub-vacuum chamber to the material storage means is provided, or from the attached material storage means of the vacuum chamber to the second sub-vacuum chamber. You may arrange | position the sticking material transfer means which transfers in the state which hold | maintained a vacuum. Thus, the sub vacuum chambers may be provided at two places. Further, the first sub-vacuum chamber and the second sub-vacuum chamber may be used together, or the material transfer means and the adhered material transfer means may be used together. The material transfer means and the attached material transfer means mount an object on the arm of the robot or transfer it by sandwiching it with the arm of the robot.

By doing so, the glass plate and the semiconductor wafer can be continuously supplied from the atmosphere without breaking the vacuum of the vacuum chamber, and the attached material can be continuously taken out to the atmosphere.

Work efficiency is improved because the substrate and the wafer are transferred onto the heating means arranged in the vacuum chamber and set to the attachment temperature to form the adhered object, and the heating means is not heated or cooled once each. Will get better. Further, since the substrates and the wafer are placed in the vacuum chamber with the bonding surfaces thereof separated from each other, air bubbles are not bitten between the wafers.

[0035]

Since the substrate and the wafer are bonded on the heated heating means, the heating efficiency is improved because the heating means is not heated or cooled once.

Further, since a plurality of substrates and wafers are placed in the vacuum chamber, and the substrates and wafers are taken out one by one and adhered to each other, and the adhered object is taken out from the heating means into the vacuum chamber, a plurality of continuous substrates can be continuously formed. Then you can paste it.

Further, since the substrate, the wafer, and the adhered material can be taken in and out through the sub-vacuum chamber in a state where the vacuum chamber is evacuated, the bonding work can be continuously performed.

Further, since the pasting object is formed by heating after preheating, the pasting can be done in a short time.

Further, since pressure is applied at the time of sticking, sticking can be done in a short time.

Further, since the semiconductor wafer and the glass plate are bonded to each other with a negative resist in a vacuum, air is not trapped between the adhesives, so that the adhesives are not peeled or the wafer is not cracked.

[Brief description of drawings]

FIG. 1 is a sectional view of a wafer sticking apparatus of the present invention.

FIG. 2 is a sectional view of a conventional wafer sticking device.

[Explanation of symbols]

 3 Vacuum Chamber 6 Wafer (Semiconductor Wafer) 7 Adhesive (Second Negative Resist) 8 Adhesive (First Negative Resist) 9 Substrate (Glass Plate) 10 Heating Means (Hot Plate) 13 Attached Material 14 Material Storage Means (Spare) Heating plate)

Claims (11)

[Claims] 1. A method for applying an adhesive to at least one surface of a substrate and a wafer, and adhering the substrate and the wafer with an adhesive application surface, wherein the adhering surfaces of the substrate and the wafer are separated from each other. The step of placing the material on the material storage means in the evacuated vacuum chamber in the state, and the transfer of the substrate and the wafer to the heating means arranged in the vacuum chamber and brought to the attachment temperature to form the attachment. A method of attaching a wafer, comprising: 2. The step of placing the substrate on the material storage means places a plurality of the substrates and the wafer, respectively, and the step of forming the attached material attaches the substrate and the wafer one by one. 2. The wafer bonding method according to claim 1, further comprising the step of removing the bonded material from the heating means and mounting it on the bonded material storage means in the vacuum chamber, and forming the bonded material sequentially. . 3. A step of transferring the vacuum chamber to the material storage means while maintaining a vacuum, through a sub-vacuum chamber capable of exhausting the substrate and the wafer from the atmosphere, and the pasting object. 3. The sub-vacuum chamber capable of evacuating the pasted material from the storage means, and taking out the vacuum chamber to the atmosphere in a vacuum-held state, the method according to claim 1 or claim 2. Wafer attachment method. 4. The method according to claim 1, wherein the step of forming the pasting object is performed after preheating during the step of placing the substrate and the wafer on the material storage means. Item 5. The method for attaching a wafer according to item 3. 5. The wafer sticking method according to claim 1, 2, 3, or 4, wherein the sticking object is pressed on the heating means. 6. The adhesive of claim 1, wherein the adhesive is a photoresist, claim 2, claim 3, claim 4,
Alternatively, the wafer bonding method according to claim 5. 7. A device for applying an adhesive to at least one surface of a substrate and a wafer, and adhering the substrate and the wafer on an adhesive-applied surface, wherein the adhering surfaces of the substrate and the wafer are separated from each other. In this state, the material storage means is placed in a vacuum, the heating means is heated to the bonding temperature, and the substrate and the wafer are transferred from the material storage means to the heating means to form a bonded object. A wafer sticking apparatus having a sticking means and a vacuum chamber accommodating them. 8. The material storage means is capable of mounting a plurality of substrates and the wafer, respectively, and a bonded material storage means for mounting a plurality of the bonded materials is disposed in the vacuum chamber, 8. The sticking means has a function of taking out the sticking material on the heating means onto the sticking material storage means, or the sticking-out means is provided in the vacuum chamber. Wafer bonding equipment. 9. A sub-vacuum chamber that can be evacuated, and a material transfer that transfers the substrate and the wafer from the atmosphere to the material storage means via the sub-vacuum chamber while the vacuum chamber is held in vacuum. A mounting means and a pasting material transfer means for transferring the pasting material from the pasting material storage means to the atmosphere via the sub-vacuum chamber in a state where the vacuum chamber is held in vacuum 9. The wafer bonding apparatus according to claim 7, wherein the wafer bonding apparatus is a wafer bonding apparatus. 10. The wafer sticking device according to claim 7, wherein a pressing means for pressing the sticking object placed on the heating means is provided. apparatus. 11. The wafer sticking apparatus according to claim 7, 8, 9, or 10, wherein said material storage means comprises a preheating means.