This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-309742, filed Oct. 10, 2000, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
This invention relates to a manufacturing method of a semiconductor device and more particularly to a method applied to a manufacturing process of a semiconductor chip obtained by adhering a film-like die bonding agent to a semiconductor chip which is made thin and formed into a discrete form by a dicing before grinding method.
2. Description of the Related Art
In order to simplify the step of mounting a semiconductor chip (pellet) on a metal frame or a printed circuit board such as organic substrate, a semiconductor chip having a film-like die bonding agent adhered to the rear surface thereof or a so-called semiconductor chip with an adhesive agent is used.
Conventionally, the semiconductor chip with the adhesive agent is formed by the steps as shown in FIGS. 1A to 1E. That is, first, as shown in FIG. 1A, a film-like adhesive agent (adhesive film) 12 is adhered by laminating, for example, to the entire portion of the rear surface (the rear surface opposite to the element forming surface) of a semiconductor wafer 11 in which formation of elements is completed.
Then, after a portion of the adhesive film 12 which is not adhered to the wafer 11 is removed, an adhesive film surface thereof is adhered to a dicing tape 14 mounted on a wafer ring 13 as shown in FIG. 1B.
After this, as shown in FIG. 1C, the wafer 11 is diced together with the adhesive film 12 along dicing lines 16 by use of a dicer 15.
Next, as shown in FIG. 1D, each of semiconductor chips is picked up by use of a pickup needle, for example, from the wafer which has been diced and formed into a discrete form and a semiconductor chip 17 with an adhesive agent is formed as shown in FIG. 1E.
Then, the surface of the semiconductor chip 17 with the adhesive agent on the adhesive film 12 side is pressed against a metal frame or a printed circuit board such as organic substrate and it is mounted on the metal frame or organic substrate.
In recent years, it is desired to make thin the semiconductor chip in order to mount the semiconductor chip on a card-like thin package or reduce the mounting area by stacking and mounting a plurality of semiconductor chips. However, if the rear surface of the wafer on which elements have been formed is ground to make the wafer thin and the wafer which is made thin is diced and divided into individual semiconductor chips, the wafer may be cracked or the rear surface chipping occurs at the time of dicing or transfer of the wafer between the steps.
A method for suppressing breakage of the wafer or occurrence of the rear surface chipping caused by making the semiconductor chip thin to a minimum degree is a dicing before grinding (DBG which is an abbreviation of Dicing Before Grinding) method described in U.S. Pat. No. 4,722,130, for example. In the dicing before grinding method, the wafer is simultaneously made thin and formed into a discrete from by grinding the rear surface of the wafer after cuts (grooves) are made to a preset depth in the element forming surface of the wafer.
However, in order to form the semiconductor chips with the adhesive agent described above by use of the semiconductor chips which are made thin and formed into a discrete form by the dicing before grinding method, it becomes necessary to adhere an adhesive film to the divided semiconductor chips by laminating, for example, and then dice only the adhesive film, and thus the manufacturing process becomes complicated.
To prevent the manufacturing process from becoming complicated, a manufacturing method as shown in FIGS. 2A and 2B is proposed. In the method, as shown in FIG. 2A, adhesive films 22 having substantially the same size as the semiconductor chip are previously affixed to a portion of a metal frame or a printed circuit board such as organic substrate 21 on which the semiconductor chip will be die-mounted.
Next, as shown in FIG. 2B, semiconductor chips 23 are pressed against and die-bonded on and mounted on the respective adhesive films 22.
However, with the above manufacturing method, since the adhesive films 22 and semiconductor chips 23 are separately pressed against, positional deviation tends to occur between the adhesive film 22 and the semiconductor chip 23. Therefore, there occurs a problem that the precision of the mounting position is lowered. Accordingly, it becomes necessary to newly introduce a highly precise film sticking machine or the like in order to press the adhesive films 22 against and mount the same on the metal frame or printed circuit board 21 with high positioning precision.
As described above, the conventional manufacturing method of the semiconductor device for forming the semiconductor chip with the adhesive agent has a problem that the manufacturing process becomes complicated if the dicing before grinding method is used. Further, if an attempt is made to prevent the manufacturing process from becoming complicated, positional deviation tends to occur between the adhesive film and the semiconductor chip, the precision of the mounting position is lowered and a highly precise film sticking machine is required.
According to an aspect of the present invention, there is provided a method for manufacturing a semiconductor device comprising: dicing a semiconductor wafer on which elements have been formed and grinding a rear surface of the semiconductor wafer by a dicing before grinding method to form discrete semiconductor chips; adhering each of the discrete semiconductor chips to an adhesive film having a first surface and a second surface; the film comprising thermoplastic resin, unset thermosetting resin or a combination of thermoplastic resin and unset thermosetting resin, and the first surface of the adhesive film being adhered to the rear surface of the semiconductor chips; removably affixing the second surface of the adhesive film to a dicing tape; and removing any excess portions of the adhesive film disposed between the respective semiconductor chips.
According to another aspect of the present invention, there is provided a manufacturing method of a semiconductor device comprising: dicing a first surface of a semiconductor wafer on which elements have been formed and grinding a rear surface of the semiconductor wafer by a dicing before grinding method to form discrete semiconductor chips; adhering each of the discrete semiconductor chips on an adhesive film which has a first surface and a second surface and a die bonding agent which comprises thermoplastic resin, unset thermosetting resin or a combination of thermoplastic resin and unset thermosetting resin, and is depolymerized by UV rays whereby a first surface of the adhesive film becomes adhered to the semiconductor chips; affixing to the second surface of the adhesive film a dicing tape; applying UV rays to the wafer from above to cause a depolymerization reaction on any excess portions of the adhesive film disposed between the respective semiconductor chips; and removing the depolymerized adhesive film.
According to still another aspect of the present invention, there is provided a manufacturing method of a semiconductor device comprising: dicing a semiconductor wafer on which elements have been formed and grinding a rear surface of the semiconductor wafer by a dicing before grinding method to form discrete semiconductor chips; adhering each of the discrete semiconductor chips on an adhesive film which has a first surface and a second surface and a die bonding agent which comprises thermoplastic resin, unset thermosetting resin or a combination of thermoplastic resin and unset thermosetting resin, and subjecting the excess adhesive film to crosslinking and polymerization reactions by applying UV rays; affixing the second surface of the adhesive film to a dicing tape; applying UV rays to the wafer from above to cause crosslinking and polymerization reactions in any portions of an excess adhesive film disposed between the respective semiconductor chips; and removing the respective semiconductor chips from the dicing tape; wherein the portions of the adhesive film which are adhered to the respective semiconductor chips are kept adhered to the respective semiconductor chips and the excess portions of the adhesive film which are subjected to crosslinking and polymerization reactions are left on the dicing tape.
According to another aspect of the present invention, there is provided a manufacturing method of a semiconductor device comprising: dicing a first surface of a semiconductor wafer on which elements have been formed and grinding a rear surface of the semiconductor wafer by a dicing before grinding method to form discrete semiconductor chips; adhering each of the discrete semiconductor chips onto an adhesive film which has a first surface and a second surface and a die bonding agent which comprises thermoplastic resin, unset thermosetting resin or a combination of thermoplastic resin and unset thermosetting resin; affixing to the second surface of the adhesive film a dicing tape; and selectively applying laser light to any portions of an excess adhesive film disposed between the respective semiconductor chips to remove the excess adhesive film.
According to another aspect of the present invention, there is provided a manufacturing method of a semiconductor device comprising: dicing a first surface of a semiconductor wafer on which elements have been formed and grinding a rear surface of the semiconductor wafer by a dicing before grinding method to form discrete semiconductor chips; adhering each of the discrete semiconductor chips onto an adhesive film which has a first surface and a second surface and a die bonding agent which comprises thermoplastic resin, unset thermosetting resin or a combination of thermoplastic resin and unset thermosetting resin; affixing to the second surface of the adhesive film a dicing tape; and removing any portions of the excess adhesive film which is disposed between the respective semiconductor chips by a cutting tool.
According to another aspect of the present invention, there is provided a method for making a semiconductor device comprising: dicing a semiconductor wafer on which elements have been formed on a top surface thereof, and grinding a bottom surface thereof, to form discrete semiconductor chips in the form of wafer; applying an adhesive film to the bottom surface of the wafer; removably adhering dicing tape to the adhesive film; and removing any excess adhesive film between the discrete semiconductor chips of the wafer.
According to another aspect of the present invention, there is provided in a method for making a semiconductor device including dicing a semiconductor wafer on which elements have been formed on a top surface thereof and grinding a bottom surface thereof to form discrete semiconductor chips in the form of a wafer, wherein the improvement comprises: applying an adhesive film to the bottom surface of the wafer; removably adhering dicing tape to the adhesive film; and removing any excess adhesive film between semiconductor chips of the wafer.
According to another aspect of the present invention, there is provided in a method for making a semiconductor device including forming discrete semiconductor chips in the form of a wafer having top and bottom surfaces, wherein the improvement comprises: applying an adhesive film to the bottom surface of the wafer; removably adhering dicing tape to the adhesive film; and removing any excess adhesive film between semiconductor chips of the wafer.
According to another aspect of the present invention, there is provided a semiconductor device produced from a method of making a semiconductor device including forming discrete semiconductor chips in the form of a wafer having a top and a bottom surface, wherein the improvement comprises: applying an adhesive film to the bottom surface of the wafer; removably adhering dicing tape to the adhesive film; and removing any excess adhesive film between the discrete semiconductor chips of the wafer.
According to another aspect of the present invention, there is provided a semiconductor device produced from a method for making a semiconductor device including dicing a semiconductor wafer on which elements having been formed on a top surface thereof and grinding a bottom surface thereof to form discrete semiconductor chips in the form of wafer, wherein the improvement comprises: applying an adhesive film to the bottom surface of the wafer; removably adhering dicing tape to the adhesive film; and removing any excess adhesive film between the discrete semiconductor chips of the wafer.