JP7768705B2 - Ring frame and method of manufacturing the ring frame - Google Patents

Description

The present invention relates to a ring frame with a central opening to which tape is attached to close the opening, and a method for manufacturing the same.

In the device chip manufacturing process, workpieces such as semiconductor wafers and package substrates with multiple devices formed on their surfaces are processed using processing equipment. The workpieces are then divided into individual devices to form individual device chips. The formed device chips are then mounted in electronic devices for use.

When a workpiece is loaded into the processing device, a frame unit is formed by integrating the workpiece with a ring frame having an opening in the center and adhesive tape attached to the ring frame to cover the opening. In the frame unit, the workpiece is housed within the opening of the ring frame.

Forming a frame unit makes it easier to handle the workpiece. Furthermore, when the workpiece is divided into individual device chips, each device chip remains attached to the adhesive tape, making the device chips that are formed easier to handle. Furthermore, if the adhesive tape is expanded radially outward inside the opening of the ring frame after the workpiece is divided, the spacing between the individual device chips increases, making it easier to pick up each device chip.

After the device chip is separated from the frame unit, the adhesive tape is peeled off from the ring frame in order to reuse the ring frame. However, at this time, the glue layer (adhesive layer) on the adhesive tape tends to remain on the ring frame, making its removal time-consuming.

A technology has been developed to attach adhesive tape to a ring frame via double-sided tape with an adhesive layer whose adhesive strength decreases when a predetermined amount of energy is applied (see Patent Document 1). When peeling the adhesive tape from the ring frame, if the predetermined amount of energy is applied to the double-sided tape in advance to reduce the adhesive strength of the adhesive layer, the adhesive layer is less likely to remain on the ring frame. However, applying sufficient energy to the double-sided tape is time-consuming, and uneven energy can sometimes occur, resulting in the adhesive layer remaining on the ring frame.

In addition, a technology has been developed in which a sheet without an adhesive layer is prepared instead of adhesive tape, a frame is prepared with a ring-shaped portion and a pressing portion, each of which has an opening, and the outer periphery of the sheet is clamped between the ring-shaped portion and the pressing portion (see Patent Document 2). However, this requires a dedicated structure or additional process to attach the sheet without an adhesive layer to the workpiece.

Japanese Patent Application Laid-Open No. 2004-193237 JP 2019-110198 A

Therefore, there was a need to develop a ring frame that could be used with conventional adhesive tapes with adhesive layers, and that would not leave any adhesive layer behind when the adhesive tape was finally removed.

The present invention was made in consideration of these problems, and its purpose is to provide a ring frame that does not easily leave an adhesive layer of adhesive tape behind when the attached adhesive tape is peeled off, and a method for manufacturing such a ring frame.

According to one aspect of the present invention, there is provided a thin plate-shaped ring frame having an opening in the center,
A ring frame is provided, characterized in that one surface thereof is provided with a nickel composite coating having fine particles of a fluorine compound dispersed and fixed therein, at least in an area including the area in contact with the edge of the opening .

Preferably, the other surface is also provided with the nickel composite coating with fine particles of the fluorine compound dispersed and fixed therein.

More preferably, the fluorine compound is polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, or perfluoroalkoxy fluororesin.

According to another aspect of the present invention, there is provided a method for manufacturing a thin-plate ring frame having an opening in the center, which comprises degreasing a stainless steel frame having an opening in the center, pickling the stainless steel frame, nickel strike plating the stainless steel frame, nickel polytetrafluoroethylene composite plating the stainless steel frame, and then washing and drying the stainless steel frame to form a ring frame having a nickel polytetrafluoroethylene composite plating layer formed on a surface area including at least the area in contact with the edge of the opening .

Preferably, the nickel-polytetrafluoroethylene composite plating is electrolytic plating.

A ring frame according to one embodiment of the present invention is provided with a nickel composite coating in which fine particles of a fluorine compound are dispersed and fixed. This nickel composite coating has a low coefficient of friction, which reduces the adhesive force when adhesive tape is applied to its outer surface. This makes it easy to peel the adhesive tape from the ring frame, and makes it less likely that an adhesive layer will remain on the ring frame.

Generally, it is desirable for adhesive tape to be attached to the ring frame with high adhesive strength so that it can stably support the workpiece. In contrast, the ring frame of one aspect of the present invention reduces the adhesive strength while ensuring the necessary adhesive strength of the attached adhesive tape, thereby preventing the adhesive layer from remaining on the ring frame.

The present invention therefore provides a ring frame in which the adhesive layer of the adhesive tape is less likely to remain when the applied adhesive tape is peeled off, as well as a method for manufacturing such a ring frame.

FIG. 2 is a perspective view schematically showing a workpiece. FIG. 10 is a perspective view schematically showing a state in which a ring frame and a workpiece are placed on a chuck table. FIG. 10 is a perspective view schematically showing how the adhesive tape is placed on the ring frame and the workpiece. FIG. 4A is a perspective view that schematically shows how unnecessary portions of the adhesive tape are cut off, and FIG. 4B is a perspective view that schematically shows a frame unit. FIG. 1 is a perspective view schematically showing how Ni-PTFE electrolytic composite plating is carried out. 10 is a flowchart showing the flow of each step in a method for manufacturing a ring frame.

An embodiment of one aspect of the present invention will be described with reference to the accompanying drawings. The ring frame of this embodiment is used to form a frame unit when a workpiece is loaded into a processing device. Figure 1 is a perspective view schematically showing the surface 1a of the workpiece 1 that is integrated with the ring frame.

The workpiece 1 is, for example, a substantially circular substrate made of a material such as Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), or other semiconductor material, or a material such as sapphire, glass, or quartz. Examples of such glass include alkali glass, alkali-free glass, soda-lime glass, lead glass, borosilicate glass, and quartz glass.

The surface 1a of the workpiece 1 is partitioned by a plurality of planned division lines 3 arranged in a grid pattern. Furthermore, devices 5 such as ICs (Integrated Circuits) and LSIs (Large-Scale Integration) are formed in each area of the surface 1a of the workpiece 1 partitioned by the planned division lines 3. When the workpiece 1 is divided along the planned division lines 3 by a processing device, device chips each equipped with a device 5 can be formed.

Before the workpiece 1 is loaded into the processing device that divides it, the workpiece 1, adhesive tape 9, and ring frame 7 are integrated to form a frame unit 11, as shown in Figure 4(B).

The workpiece 1 is loaded into the processing device in the frame unit 11 state and processed. The individual device chips formed in the processing device are supported directly on the adhesive tape 9. The adhesive tape 9 is then expanded radially outward inside the opening 7a of the ring frame 7, widening the spacing between the device chips and making it easier to pick up the device chips.

Figure 2 includes a perspective view showing the back side of the ring frame 7 according to this embodiment. The ring frame 7 is a thin plate-like member made of a metal material such as stainless steel (SUS), and has an opening 7a with a diameter larger than that of the workpiece 1. When forming the frame unit 11, the workpiece 1 is positioned within the opening 7a of the ring frame 7 and accommodated in the opening 7a.

The adhesive tape 9 (see Figure 3, etc.) is known as dicing tape. It is a flexible resin-based tape with flat front and back surfaces. The adhesive tape 9 has a diameter larger than the outer diameter of the ring frame 7 and is composed of a base layer and a glue layer (adhesive layer) provided on one side of the base layer. The base layer is made of a material such as polyolefin, polyvinyl chloride, or polyethylene terephthalate, and the glue layer is made of an acrylic or rubber-based material.

When the workpiece 1, adhesive tape 9, and ring frame 7 are joined together, as shown in Figure 2, the workpiece 1 and ring frame 7 are placed on the suction surface 2a of the chuck table 2. The chuck table 2 has a porous member in its upper center that has a diameter larger than the outer diameter of the ring frame 7. The upper surface of this porous member becomes the suction surface 2a of the chuck table 2.

As shown in Figure 3, the chuck table 2 has an internal exhaust passage with one end connected to the porous member, and a suction source 2b is provided at the other end of the exhaust passage. The exhaust passage is provided with a switching unit 2c that switches between a connected state and a cut state. When the switching unit 2c is in the connected state, negative pressure generated by the suction source 2b acts on the object to be held placed on the suction surface 2a, causing the object to be held by suction to the chuck table 2.

Next, as shown in Figure 3, adhesive tape 9 is placed over the workpiece 1 and the ring frame 7 so as to cover them both. If adhesive tape 9 with a diameter larger than the suction surface 2a of the chuck table 2 is used, when negative pressure from the chuck table 2 is applied to the adhesive tape 9, the entire suction surface 2a is covered by the adhesive tape 9, preventing leakage of the negative pressure.

When adhering the adhesive tape 9 to the workpiece 1 and ring frame 7, the switching unit 2c is operated to apply negative pressure from the suction source 2b to the adhesive tape 9, etc. The adhesive tape 9 is then pressed from above by atmospheric pressure, adhering the adhesive tape 9 to the workpiece 1 and ring frame 7. Note that the adhesive tape 9 may be pressed from above with a roller or the like to strengthen the adhesive force of the adhesive tape 9 to the workpiece 1 and ring frame 7.

After the adhesive tape 9 has been adhered to the workpiece 1 and ring frame 7 in this way, the switch 2c is again operated to shut off the negative pressure of the suction source 2b. Then, as shown in Figure 4(A), the cutter 4 is used to cut the adhesive tape 9 on the ring frame 7, and the unnecessary portion of the adhesive tape 9 is removed outside the cutting groove 9a. This completes the formation of the frame unit 11, as shown in Figure 4(B).

The frame unit 11 is loaded into a processing device, which separates the workpiece 1. The formed device chips are then picked up from the adhesive tape 9 and mounted on the desired target. The adhesive tape 9 is then peeled off from the ring frame 7 and discarded, and the ring frame 7 is cleaned and reused. At this time, the adhesive layer of the adhesive tape 9 tends to remain partially on the ring frame 7, making removal of the adhesive layer time-consuming.

To prevent this, the ring frame 7 according to this embodiment is provided with a nickel composite coating with fine particles of a fluorine compound dispersed and fixed on its outer surface, so that the adhesive layer is less likely to remain when the adhesive tape 9 is peeled off. This composite coating has an extremely low coefficient of friction, allowing the applied adhesive tape 9 to be easily peeled off, and the adhesive layer is less likely to remain on the composite coating. This allows the used ring frame 7 to be reused without significant effort.

Next, we will explain the manufacturing method for a ring frame 7 having a nickel composite coating on its outer surface with fine particles of a fluorine compound dispersed and fixed thereon. Figure 6 is a flowchart showing the steps in this manufacturing method. Below, we will explain this manufacturing method using as an example the case where a ring frame 7 is manufactured by disposing a nickel-polytetrafluoroethylene (Ni-PTFE) composite plating layer as the nickel composite coating on a stainless steel frame.

A stainless steel frame 13 (see Figure 5) is used as the raw material to manufacture the ring frame 7. For example, the stainless steel frame 13 is a conventional ring frame that is integrated with a workpiece 1 such as a semiconductor wafer and an adhesive tape 9 such as dicing tape to form a frame unit 11. An opening with a diameter larger than the diameter of the workpiece 1 is formed in the center of the stainless steel frame 13.

First, the stainless steel frame 13 is subjected to a degreasing process S10. The degreasing process S10 is a process in which various types of dust, oil, and other organic matter adhering to the surface of the stainless steel frame 13 are removed from the stainless steel frame 13 using an organic solvent or alkaline solution. Performing the degreasing process S10 enables a uniform film formation when forming a Ni-PTFE composite plating layer on the outer surface of the stainless steel frame 13, as described below.

When performing the degreasing process S10, a liquid such as an organic solvent or alkaline solution is heated and the stainless steel frame 13 is immersed in the liquid. For example, organic solvents such as trichloroethylene, tetrachloroethylene, and trichloroethane are used for the degreasing process S10. Alternatively, alkaline solutions such as aqueous sodium hydroxide solution and aqueous sodium carbonate solution are used for the degreasing process S10.

Next, the stainless steel frame 13 is subjected to an acid pickling treatment (acid activation treatment) S20. The acid pickling treatment S20 is a process in which oxide films, rust, and residual oils on the surface of the stainless steel frame 13 are removed from the stainless steel frame 13 using a strong acid such as sulfuric acid or hydrochloric acid, exposing the base material of the stainless steel frame 13. Furthermore, performing the acid pickling treatment S20 creates minute irregularities on the surface of the stainless steel frame 13, which increases the adhesion of the Ni-PTFE composite plating layer that will be formed later to the outer surface of the stainless steel frame 13.

Next, nickel strike plating S30 is performed on the stainless steel frame 13. Nickel strike plating S30 is a process for applying a base plating to the surface of the stainless steel frame 13. Nickel strike plating S30 is performed to prevent the formation of a new passive film on the surface of the stainless steel frame 13 after the pickling treatment S20, while also improving the adhesion of the Ni-PTFE composite coating (described below) to the surface.

In nickel strike plating S30, the stainless steel frame 13 and nickel metal plate are immersed in a strongly acidic plating bath called a Wood's bath, which is composed of nickel chloride and hydrochloric acid, and electricity is passed between the stainless steel frame 13 and the nickel metal plate. This forms a nickel strike plating layer as a thin base film on the surface of the stainless steel frame 13.

Next, nickel polytetrafluoroethylene (Ni-PTFE) composite plating S40 is performed on the stainless steel frame 13 with the nickel strike plating layer formed on its surface. Figure 5 is a perspective view that schematically shows how Ni-PTFE composite plating S40 is performed. Ni-PTFE composite plating S40 is performed, for example, in a plating device 6 having a rectangular container 8 made of polyvinyl chloride. In Figure 5, the internal components of the container 8 are drawn with solid lines for ease of explanation, but the container 8 and the plating solution 10 contained therein are not necessarily transparent.

Container 8 contains plating solution 10. Plating solution 10 contains nickel sulfamate, nickel chloride, boron, a primary brightener, a secondary brightener, and a polytetrafluoroethylene dispersion (PTFE dispersion). The PTFE dispersion is a liquid in which, for example, PTFE with a particle size of 1 μm or less is dispersed at 25 to 28 vol%. A nickel metal plate 16 is used as the anode.

In Ni-PTFE composite plating S40, a stainless steel frame 13 and a nickel metal plate 16 are immersed in plating solution 10 contained in a container 8. Then, an electric current is passed through the plating solution via wiring 12 connected to the stainless steel frame 13 and wiring 14 connected to the nickel metal plate 16.

At this time, the current density on the surface of the stainless steel frame 13 is set to 5 A/ ^dm² , and electrolytic plating is performed for a time period sufficient to form a Ni-PTFE composite plating layer having a thickness of 2 μm to 10 μm. Specifically, the time period is expected to be 2 minutes to 10 minutes, or a similar period. When the Ni-PTFE composite plating S40 is performed, a nickel composite coating with dispersed and fixed PTFE particles, i.e., a Ni-PTFE composite plating layer, is formed on the surface of the stainless steel frame 13.

Then, the stainless steel frame 13 is lifted out of the container 8 and washed and dried (S50). Specifically, the stainless steel frame 13 with the plating solution 10 attached is immersed in water contained in a cleaning tank to remove the attached plating solution 10, and the stainless steel frame 13 is lifted out of the cleaning tank and dried to remove the attached water. This results in the formation of a ring frame 7 with a nickel-polytetrafluoroethylene composite plating layer formed on its surface as a nickel composite coating.

Note that during the process of manufacturing the ring frame described above, i.e., between each step, the stainless steel frame 13 may be washed with a liquid such as water as appropriate. Washing the stainless steel frame 13 with water or the like can prevent excessive chemical reactions from progressing. It also makes the stainless steel frame 13 easier to handle.

The surface of the ring frame 7, which has a nickel composite coating formed on it with fine particles of polytetrafluoroethylene (PTFE) dispersed and fixed as a fluorine compound, has an extremely low coefficient of friction. Therefore, when adhesive tape 9 is applied to the surface of the ring frame 7, its adhesive force is reduced. Therefore, after processing the workpiece 1 included in the frame unit 11, the adhesive tape 9 can be easily peeled off from the ring frame 7, and the adhesive layer of the adhesive tape 9 is less likely to remain on the ring frame 7.

Generally, it is desirable for the adhesive tape 9 to be attached to the ring frame with high adhesive strength so that the workpiece 1 can be stably supported. However, the ring frame 7 of this embodiment ensures the necessary adhesive strength of the attached adhesive tape 9 while reducing the adhesive strength, thereby preventing the adhesive layer from remaining on the ring frame 7.

Furthermore, if a nickel composite coating with dispersed and fixed fine particles of a fluorine compound is formed on the outer surface of the ring frame 7, the ring frame 7 will also be resistant to dirt other than the adhesive layer. For example, when processing the workpiece 1, processing debris will be generated from the workpiece 1 and the processing tool. The processing debris may come into contact with the outer surface of the ring frame 7, and it is possible that the processing debris will adhere to the ring frame 7.

However, when a nickel composite coating with dispersed and fixed fluorine compound particles is formed on the outer surface, processing debris is less likely to adhere to the ring frame 7. Furthermore, even if processing debris does adhere to the ring frame 7, it can be easily removed from the ring frame 7 in a subsequent cleaning process. In other words, the ring frame 7 is resistant to dirt other than the adhesive layer.

In the above embodiment, an example was described in which a nickel composite coating with dispersed and fixed fine particles of a fluorine compound is formed on all outer surfaces of the ring frame 7, but this aspect of the present invention is not limited to this. For example, in a ring frame 7 according to one aspect of the present invention, a nickel composite coating with dispersed and fixed fine particles of a fluorine compound may be formed on only one surface of the ring frame 7, and the nickel composite coating may not be formed on the other surface.

In this case, when integrating the workpiece 1, ring frame 7, and adhesive tape 9 to form the frame unit 11, the worker can select the surface of the ring frame 7 to which the adhesive tape 9 will be attached. For example, if you do not want to leave the adhesive layer of the adhesive tape 9 on the ring frame 7 so that the ring frame 7 can be easily reused, when forming the frame unit 11, it is recommended that the adhesive tape 9 be attached to the one surface of the ring frame 7 on which the nickel composite coating is formed.

On the other hand, depending on the weight of the workpiece 1 and the type of processing to be performed on the workpiece 1, it may be desirable to adhere the adhesive tape 9 to the ring frame 7 with strong adhesive strength. In this case, it is advisable to adhere the adhesive tape 9 to the other side of the ring frame 7 on which the nickel composite coating is not formed. In this way, if the nickel composite coating is provided on only one side of the ring frame 7, the adhesive surface of the adhesive tape 9 can be used depending on the purpose.

To form the nickel composite coating only on a portion of the outer surface of the ring frame 7, it is advisable to carry out a process such as Ni-PTFE composite plating S40 while masking the remaining portions of the outer surface of the ring frame 7. Possible methods for masking include applying chemical-resistant tape or applying a chemical-resistant resist.

The nickel composite coating may be provided not only on one surface of the ring frame 7 but also on the other surface. In this case, the worker will not have to worry about which surface of the ring frame 7 to apply the adhesive tape 9 to.

In addition, in the above embodiment, the fluorine compound particles dispersed and fixed in the nickel composite coating were described as being polytetrafluoroethylene (PTFE), but the material of the fluorine compound is not limited to this. The type of fluorine compound can be selected appropriately depending on the properties required for the outer surface of the ring frame 7.

That is, the fluorine compound dispersed and fixed in the nickel composite coating may be, for example, polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), or perfluoroalkoxy fluororesin (PFA).

Furthermore, in the above embodiment, the Ni-PTFE composite plating S40 is described as being performed by electrolytic plating, but this aspect of the present invention is not limited to this. In other words, the Ni-PTFE composite plating S40 may also be performed by electroless plating.

In addition, the structures, methods, etc. related to the above embodiments can be modified as appropriate without departing from the scope of the present invention.

REFERENCE SIGNS LIST 1 Workpiece 3 Planned division line 5 Device 7 Ring frame 9 Adhesive tape 9a Cutting groove 11 Frame unit 13 Stainless steel frame 2 Chuck table 2a Suction surface 2b Suction source 2c Switching unit 4 Cutter 6 Plating device 8 Container 10 Plating solution 12, 14 Wiring 16 Nickel metal plate

Claims (5)

A thin plate-shaped ring frame having an opening in the center,
A ring frame characterized in that one surface thereof is provided with a nickel composite coating having fine particles of a fluorine compound dispersed and fixed therein, in an area including at least an area in contact with the edge of the opening . The ring frame according to claim 1, characterized in that the nickel composite coating with fine particles of the fluorine compound dispersed and fixed therein is also provided on the other surface. The ring frame according to claim 1 or 2, characterized in that the fluorine compound is one of polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, and perfluoroalkoxy fluororesin. A method for manufacturing a thin plate-shaped ring frame having an opening in the center, comprising:
A stainless steel frame with a central opening is degreased,
The stainless steel frame is subjected to an acid pickling treatment;
The stainless steel frame is nickel strike plated;
The stainless steel frame is subjected to nickel polytetrafluoroethylene composite plating,
The stainless steel frame is washed and dried to
A method for manufacturing a ring frame, comprising forming a ring frame having a nickel-polytetrafluoroethylene composite plating layer formed on a surface thereof, at least in an area including an area in contact with the edge of the opening . The method for manufacturing a ring frame described in claim 4, characterized in that the nickel-polytetrafluoroethylene composite plating is electrolytic plating.