JP5935303B2 - Spray nozzle and resist film forming apparatus - Google Patents

Description

  The present invention relates to a spray nozzle and a resist film forming apparatus.

  In recent years, a technique called TSV has attracted attention as one of high-density packaging techniques in semiconductor devices. This TSV is a technique for connecting chips stacked by using a through electrode that penetrates the chip. For example, one described in Patent Document 1 below is known. An example of a TSV manufacturing process will be briefly described. First, a bottomed recess called a via hole is formed on the surface of a wafer, and a resist film is formed along the inner wall of the via hole. Next, by exposing and developing, only the resist film formed on the bottom of the via hole is removed. Subsequently, by performing dry etching, the wafer exposed at the bottom of the via hole is removed. Then, after the resist film in the via hole is peeled off, copper plating is performed in the via hole, thereby forming a through electrode penetrating the chip.

JP2011-96918A

The resist film as described above is generally applied by a method called spin coating. However, since the TSV via hole described above is formed with a small diameter and deep, it is difficult to apply the resist solution to the bottom of the via hole.
The present invention has been completed based on the above-described circumstances, and an object thereof is to apply a resist solution up to the bottom of a bottomed recess.

The present invention is a spray nozzle that forms a resist film by spraying a resist solution toward a wafer having a bottomed concave portion formed on a surface thereof, and a resist solution supply path for supplying the resist solution is along an axis. A main shaft that penetrates the main shaft, an air turbine in which the main shaft is housed , a bearing that rotatably supports the air turbine, and a tip that is attached to the tip of the air turbine and rotates to form the resist. A spray nozzle comprising a cup for atomizing a liquid, wherein the air turbine and the bearing are made of non-metal.

  According to such a configuration, since the resist solution is sprayed toward the wafer by the rotary atomizing spray nozzle, the resist solution can be applied to the bottom of the recess. In other words, the resist liquid droplets can be made minute by atomizing the resist liquid by rotating the cup. When the resist liquid droplets are miniaturized, it becomes easier to apply the resist liquid to the bottom of the recess. Therefore, a resist film can be formed along the inner wall of the recess. Further, since the main shaft and the bearing are made of non-metal, even if the main shaft and the bearing slide to generate debris, there is no possibility that the debris will fall on the wafer and short circuit between the circuits.

The following configuration is preferable as an embodiment of the present invention.
The air turbine and the bearing may be made of resin.
According to such a configuration, since the weight can be reduced as compared with the metal main shaft, the rotation speed of the main shaft can be increased. Further, when the rotational speed of the main shaft is constant, the air pressure required to rotate the main shaft can be reduced compared to the metal main shaft.

The cup may be configured to be made of non-metal. The cup may be configured to be made of resin.
According to such a configuration, the spray nozzle can be reduced in weight. In particular, by reducing the weight of the cup, the cup can be rotated at a high speed, and the droplets of the resist solution can be further miniaturized. Moreover, even if the cup slides with other members to generate cup scraps, there is no possibility of short circuits between the circuits due to the scraps.

Further, the present invention provides the above-mentioned spray nozzle, an arm having a spray nozzle attached to the tip thereof, a movable head that fixes the base end of the arm, an actuator that translates the movable head, and a wafer that is sucked and fixed. And a resist film forming apparatus characterized in that a resist film is formed on a wafer by spraying a resist solution from a spray nozzle toward the wafer fixed on the plate. .
According to such a resist film forming apparatus, since the spray nozzle can be moved by moving the head, the resist liquid can be sprayed and applied to the entire surface of the wafer.

  According to the present invention, the resist solution can be applied to the bottom of the bottomed recess.

An enlarged plan view of the main part of the resist film formation system Front view with enlarged main parts of resist film forming system Cross section of spray nozzle Sectional view showing the state before applying the resist solution to the wafer surface Sectional drawing which showed the state after apply | coating resist liquid to the surface of a wafer Graph showing comparison of rotational characteristics of resin turbine and metal turbine Graph showing comparison of air consumption between resin turbine and metal turbine Graph showing the relationship between rotation speed and average droplet diameter Graph showing the relationship between shaping air pressure and average droplet velocity

<Embodiment>
An embodiment of the present invention will be described with reference to the drawings of FIGS. 1 and 2 show a resist film forming apparatus 10, which is an apparatus for forming a resist film 60 on the surface of a wafer 50 by spraying a resist solution. The wafer 50 according to the present embodiment has a circular thin plate shape and is a silicon wafer having a diameter of 200 mm. A via hole 51 for forming a through electrode in a TSV (Through-Silicon Via) is recessed in the surface of the wafer 50. The via hole 51 is formed as a bottomed recess.

  As shown in FIG. 2, the resist film forming apparatus 10 is provided with a stage 11 that sucks and fixes the wafer 50, and surrounds the wafer 50 supported by the stage 11 over the entire circumference. A mistress cup 12 is provided around. The mistress cup 12 is configured to rise upward from the outer peripheral edge of the base 13 that supports the stage 11, and restricts the resist solution bounced on the wafer 50 from being scattered to the surroundings.

  A heater (not shown) is provided inside the stage 11, and the wafer 50 is heated to an arbitrary temperature by this heater. A rotary atomizing spray nozzle 14 is disposed above the wafer 50. The spray nozzle 14 is attached to the tip of the arm 15. The base end of the arm 15 is fixed to the movable head 16, and the movable head 16 can be translated in the X direction by the X axis actuator 17, and can be translated in the Y direction by the Y axis actuator 18. ing.

  The spray nozzle 14 is made of non-metal, and the movable head 16 is translated in the X direction and the Y direction by the biaxial actuators 17 and 18 so that the spray nozzle 14 can be sprayed at an arbitrary position on the wafer 50. Yes. In the present embodiment, the spray nozzle 14 operates in a staggered manner, so that the resist solution can be applied to the entire surface of the wafer 50.

  As shown in FIG. 3, an air cup 19 made of PTFE (polytetrafluoroethylene) is rotatably attached to the lower end of the spray nozzle 14. The air cup 19 includes an injection port for injecting a resist solution. A plurality of holes and a plurality of grooves inclined in the rotation direction are formed on the inner surface 19A of the injection port of the air cup 19. The air cup 19 is attached to the tip of a resin turbine 21 made of PEEK (polyetheretherketone).

The resin turbine 21 is rotatably provided in a spindle 22 made of PEEK, and a main shaft 23 made of PEEK is accommodated in the resin turbine 21. The resin turbine 21 is supported by a pair of upper and lower bearings 25, 25 (the body material is made of PEEK and the bearing part is made of carbon). The resin turbine 21 is an air turbine air is interposed between each bearing 25, 25. Therefore, when the high-pressure air is supplied to the spindle 22, tree butter turbine 21 the air becomes the air bearing is rotated. Result of this, air cup 19 attached to the tip of the resin turbine 21 will be rotating at a high speed at the maximum 70,000 rev / min.

  Inside the main shaft 23, a resist solution supply path 23A for supplying a resist solution is formed penetrating along the axis. The supply of the resist solution to the resist solution supply path 23A is performed by supplying the resist solution to the supply port 24A of the back plate 24 that seals the upper end portion of the spray nozzle 14. Then, by rotating the resin turbine 21 at a high speed, the resist liquid is atomized and injected from the air cup 19. As a result, the resist liquid is miniaturized with a droplet diameter of several μm, and the resist liquid droplets can easily enter the inside of the small-diameter via hole 51 formed on the surface of the wafer 50.

  An air cap 20 made of PEEK is mounted around the air cup 19 in the spray nozzle 14. A shaping air hole 20A that ejects a carrier gas called shaping air at high speed is formed at the tip of the air cap 20, and the pressure of the shaping air blown out from the shaping air hole 20A (the amount of shaping air) is adjusted. As a result, the flying droplet velocity of the resist solution can be controlled. Thereby, droplets of the resist solution can be ejected at a speed of several tens of m / s. According to such a spray nozzle 14, it is possible to form the resist film 60 on the bottom and side surfaces of the via hole 51 having a frontage diameter of 20 μm to 200 μm.

  Inside the air cup 19, a catching solvent for catching a mist-like resist solution that has not been formed is accommodated. The resist solution caught by the catcher solvent is discarded as waste resist. In addition, after the catcher solvent and the waste resist are separated, the catcher solvent can be fed into the air cup 19 again. In addition, the air in the resist film forming apparatus 10 is circulated through a hepa filter, and the cleanliness of Class 100 is maintained.

  The present embodiment is configured as described above, and the procedure for subsequently forming the resist film 60 on the wafer 50 will be described with reference to FIGS. The conditions for forming the resist film 60 are as follows. The rotational speed of the air cup 19 was 70000 rpm, the shaping air pressure was 0.19 MPa, and PMER P-LA900 manufactured by Tokyo Ohka Kogyo Co., Ltd. was used as the resist used. In the spray process in which the resist solution is sprayed from the spray nozzle 14 toward the wafer 50, the wafer 50 shown in FIG. 4 is fixed to the stage 11 and the resist solution is sprayed from the spray nozzle 14 toward the wafer 50. The resist solution applied to the wafer 50 enters the via hole 51 and forms a film.

<Example>
Next, an embodiment of the present invention will be described with reference to the drawings of FIGS. FIG. 6 is a graph showing a comparison between the rotational characteristics of the resin turbine 21 and the rotational characteristics of the metal turbine. The resin turbine 21 is about 50 g, whereas the metal turbine is about 270 g, and the resin turbine 21 is reduced in weight to about one fifth of the metal turbine. Therefore, when rotating with the same shaping air pressure, the resin turbine 21 rotates at a higher speed than the metal turbine.

  FIG. 7 is a graph showing a comparison between the air consumption of the resin turbine 21 and the air consumption of the metal turbine. When the resin turbine 21 is rotated at the same shaping air pressure, the air consumption of the resin turbine 21 is It can be seen that the resin turbine 21 has less air consumption than the metal turbine.

  FIG. 8 is a graph showing the relationship between the rotational speed of the resin turbine 21 and the average droplet diameter of the resist solution. First, when the shaping air pressure is 0.16 MPa, it can be seen that as the rotational speed of the resin turbine 21 is increased, the average droplet diameter of the resist solution is gradually reduced. It can also be seen that when the shaping air pressure is 0.21 MPa, the average droplet diameter of the resist solution hardly changes even when the rotational speed of the resin turbine 21 is increased. When the rotational speed of the resin turbine 21 is 30,000 revolutions per minute, the average droplet diameter is smaller at 0.21 MPa than at 0.16 MPa, and the rotational speed of the resin turbine 21 is 70,000 per minute. In the case of rotation, it can be seen that the average droplet diameter is almost the same at 0.16 MPa and 0.21 MPa.

  FIG. 9 is a graph showing the relationship between the shaping air pressure and the average velocity of flying droplets of resist liquid (hereinafter referred to as “average droplet velocity”). It can be seen that the average droplet velocity gradually increases as the shaping air pressure is increased. This is presumably because the initial velocity when the droplet of the resist solution jumps out of the ejection port of the air cup 19 is increased. That is, when the shaping air pressure is increased, air is supplied in excess of the amount necessary to rotate the resin turbine 21, and as a result, excess air blows out from the injection port of the air cup 19, resulting in a high average droplet velocity. It is considered to be. The droplet speed and droplet diameter of the resist solution were measured using a shadow / Doppler / particle analyzer.

  As described above, in this embodiment, the resist liquid is sprayed toward the wafer 50 using the rotary atomizing spray nozzle 14, so that the resist liquid droplets are micronized to the bottom of the via hole 51. A liquid can be applied. Further, by adjusting the pressure of the shaping air hole 20 </ b> A, the atomized resist liquid droplets can be ejected at a high speed, so that the resist liquid can be reliably applied to the bottom of the via hole 51. Thereby, the spray nozzle 14 suitable for the film-forming process of the resist film 60 of the via hole 51 in TSV can be provided.

  Moreover, since the spray nozzle 14 is made of resin, it is possible to restrict a short circuit between the circuits due to, for example, falling metal scraps on the wafer. Furthermore, since the resin turbine 21 has been reduced in weight, the resin turbine 21 can be rotated at high speed, and the resist liquid droplets can be further miniaturized and the droplet speed can be further increased. Further, as the resin turbine 21 is reduced in weight, the air pressure necessary to rotate the resin turbine 21 can be reduced.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention .

  (2) Although the resin spray nozzle 14 is illustrated in the above embodiment, according to the present invention, it may be a non-metal spray nozzle, and may be applied to spray nozzles other than resin.

DESCRIPTION OF SYMBOLS 10 ... Resist film forming apparatus 11 ... Stage (plate)
14 ... Spray nozzle 15 ... Arm 16 ... Movable head 17 ... X-axis actuator (actuator)
18 ... Y-axis actuator (actuator)
19 ... Air cup (cup)
DESCRIPTION OF SYMBOLS 23 ... Main axis | shaft 23A ... Resist liquid supply path 25 ... Bearing 50 ... Wafer 51 ... Via hole (concave part)
60. Resist film

Claims (5)

A spray nozzle that forms a resist film by spraying a resist solution toward a wafer having a bottomed recess formed on the surface,
A main shaft formed by penetrating a resist solution supply path for supplying the resist solution along the axis;
An air turbine in which the main shaft is housed;
A bearing rotatably supporting the air turbine ;
It is attached to the tip of the air turbine , and comprises a cup for atomizing the resist solution by rotating,
The air turbine and the bearing are spray nozzles made of non-metal. The spray nozzle according to claim 1, wherein the air turbine and the bearing are made of resin.   The spray nozzle according to claim 1, wherein the cup is made of a non-metal.   The spray nozzle according to claim 3, wherein the cup is made of resin. A spray nozzle according to any one of claims 1 to 4,
An arm with the spray nozzle attached to the tip;
A movable head for fixing a base end of the arm;
An actuator for translating the movable head;
A plate for adsorbing and fixing the wafer,
A resist film forming apparatus, wherein a resist film is formed on the wafer by spraying the resist solution from the spray nozzle toward the wafer fixed on the plate.

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