JP3110070B2 - Mold centering method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of forming a resin (resin) on a peripheral portion of a semiconductor substrate (wafer) by using a molding die. Is used for centering of the mold when exchanging.

[0002]

2. Description of the Related Art A semiconductor device for controlling large power, for example, GT
In rectifiers such as O, to protect the wafer edge,
In many cases, resin molding is performed on the portion. As a method of forming a resin on the outer periphery of a wafer as described above, for example, there is a method disclosed in Japanese Patent Application Laid-Open No. 63-141370. In recent years, the external dimensions of the resin after forming have been used for positioning in post-process assembly. In some cases, a molding die is used to achieve dimensional accuracy.

Next, a description will be given of a semiconductor manufacturing apparatus and a resin forming method for forming a resin on the peripheral portion of a wafer by using a forming die (see Japanese Patent Application No. 2-155787).
FIG. 4 shows the resin 2 in the annular area surrounding the peripheral portion of the wafer 1.
FIG. 3 is a partially crushed perspective view of a resin molded product obtained by molding a resin. FIG.
FIG. 2 is a plan view showing the outline of the configuration of the semiconductor manufacturing apparatus. FIG. 3 is a partial sectional view of a molding unit which is one of the components of the manufacturing apparatus.

In FIG. 2, a wafer supply unit 3 has a plurality of wafers 1 mounted on a carrier, and a wafer chuck 1 attached to a carrier unit 4 moves the wafers one by one along a wafer carrier line 12 into an alignment unit. 9, are sequentially sent to the molding unit 5 and the wafer storage unit 11. An alignment unit 9 for centering the wafer has an XY table 7 on which a wafer having a positioning pattern provided at the center is placed, and corrects the center position of the wafer based on the recognition result of the automatic recognition device 8. I do. Next, the positioned wafer is sent to the forming unit 5.

In FIG. 3, a molding unit 5 includes an upper mold 1
6, upper die holder 15, upper die heater block 14, lower die 20, lower die holder 19 and lower die heater block 1
8 and a mechanism for opening and closing the upper mold and the lower mold and a temperature control mechanism. The lower mold 20 is provided with a concave region 28 (see FIG. 1) surrounded by an outer peripheral side wall of an annular cavity 27 into which the resin is injected.

At the time of resin molding, a wafer is set in the concave area 28 of the lower mold 20 mounted on the molding unit 5, and then the upper mold 16 is lowered by a mold-clamping stroke.
The upper mold and the lower mold are closed, and the resin is injected into the cavity 27 from the resin injection port 22. The injected resin is heated and solidified by a mold controlled at a constant temperature.
In this case, since the inner diameter of the concave region 28 of the lower die 20 is larger than the outer diameter of the wafer 1, when the wafer 1 is set in the concave region 28, there is a gap between the inner periphery of the concave region 28 and the outer periphery of the wafer 1. Gap occurs.

The resin 2 formed as described above has a function as a protective film on the side wall of the wafer 1 and an insulating film for holding pressure resistance. Therefore, when the width H (see FIG. 4) between the side wall of the wafer 1 and the outer peripheral side surface of the resin 2 is narrow, insulation failure tends to occur. Therefore, the misalignment between the center of the formed annular resin and the center of the wafer becomes an important problem, and it is required that the centers be accurately aligned.

[0008] Conventionally, a mold exchange in accordance with a type change is shown in FIG.
The centering is performed by fitting a hole of a lower mold holder of a mold to be exchanged into the guide 25 with reference to a cylindrical mold guide 25 of the lower mold heater block 18 shown in FIG. This varieties change is often done because the product is characterized by high-mix low-volume production. Therefore, the molds are frequently exchanged. For this reason, the wear of the mold guides 25 causes looseness in the fitting with the holes of the lower mold holder, and the heater block 18 and the lower mold are coupled in an eccentric state. As a result, the center of the wafer and the center of the ring-shaped resin do not coincide with each other, resulting in specification failure.

[0009]

In the above-mentioned prior art,
The diameter of the outer peripheral side wall (inner diameter of the concave region) of the lower die cavity of the molding die is larger than the diameter of the wafer, and a gap is formed between the inner periphery of the concave region of the lower die and the outer periphery of the placed wafer.
Therefore, there is no guarantee that the center of the recessed area always coincides with the center of the wafer when the wafer is set on the lower mold. The accuracy at which the two centers coincide with each other is determined by the accuracy of assembling the mold and the like and the accuracy of the transfer pitch of the transfer unit 4 in addition to the positioning accuracy of the wafer in the alignment unit 9. Adjusted by the manufacturer, a desired matching accuracy is obtained in actual use.

However, as in the case of the molding die guide 25 described above, when the mold is frequently replaced after the production apparatus has been operated, and there is a play in a portion to be fitted due to wear, the variation is reduced.
The center of the concave area of the lower mold and the center of the wafer to be set are varied, and the center of the formed annular resin is shifted from the center of the wafer.

There is the following method for solving this problem. In other words, when changing the mold by changing the product type,
Each time, after a required molding die is mounted and fixed on the molding unit 5, the wafer is set on the lower die by a predetermined operation. Using this as a sample, the presence or absence of eccentricity between the concave region of the lower die and the wafer is measured, and the position of the lower die is corrected. However, this method has a disadvantage that extra auxiliary work is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to form a mold without frequent effects even if a mold guide part for centering is worn out frequently. An object of the present invention is to provide a method of centering a mold with a positioning unit capable of easily detecting a center position of a mold, guaranteeing dimensional accuracy of a molded product, improving yield and reducing incidental work.

[0013]

SUMMARY OF THE INVENTION The present invention is directed to a semiconductor manufacturing apparatus for molding a resin in an annular area surrounding the periphery of a semiconductor substrate (wafer). In the centering method of the mold having the corresponding upper and lower resin injection parts)
(A) a positioning unit that has a semiconductor substrate mounting table for mounting a semiconductor substrate provided with a positioning pattern and aligns the positioning pattern with a positioning reference pattern; and (b) an upper die and a lower die, A semiconductor comprising: a molding unit having a molding die provided with a concave area surrounded by an outer peripheral side wall of the annular cavity; and (c) a transport unit that reciprocates between the alignment unit and the molding unit at a constant transport pitch. Using a manufacturing apparatus, a centering jig fitted to the concave area of the lower mold and provided with a positioning pattern on the main surface is prepared, and a centering jig is provided in the concave area of the lower mold mounted on the molding unit. After the fixtures are fitted, the centering jig is picked up and transported by the transport unit, and the positioning pattern on the jig when placed on the semiconductor mounting table of the alignment unit is moved to the position of the alignment unit. A centering method of the alignment unit, wherein the mold to be decided reference pattern. The positioning pattern provided on the wafer and the centering jig is often provided at the center of the wafer and the jig.

[0014]

According to the present invention, as a means for aligning the center of the wafer with the center of the mold, a guide is provided on the mold and the centering is performed mechanically. To solve the problem. In this centering jig, a pattern equivalent to the positioning pattern provided on the wafer is formed on the surface of the jig, and the outer diameter of the jig is made to match the inner diameter of the lower concave area.

First, a molding die is mounted and fixed on the molding unit as in the conventional case. Next, the centering jig is fitted into the concave area of the lower die. At this time, the positioning pattern provided on the jig indicates the center of the concave area of the lower die. Next, the jig fitted to the lower mold is taken out by the vacuum chuck attached to the transfer unit 4, transferred, and transferred to the wafer mounting table of the alignment unit 9. The positioning pattern on the jig at this time is detected by the automatic recognition device and stored as a positioning reference pattern of the positioning unit 9. Since the transfer unit 4 has a fixed transfer pitch (dispersion of displacement due to transfer is extremely small and can be ignored in practical use, and always transfers and mounts a wafer at a fixed pitch).
If the positioning pattern of the wafer to be processed supplied to the positioning unit is adjusted to the detected positioning reference pattern and then transferred to the forming unit 5 by the transfer unit 4, the positioning pattern of the wafer will be at the center of the lower mold concave area. Matches. That is, the wafer is set concentrically with the center of the lower die.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 2 is a plan view showing an example of the configuration of a semiconductor manufacturing apparatus used for carrying out the present invention.
Is a partial cross-sectional view of a molding unit of the manufacturing apparatus, which is the same as the conventional example, and the description is omitted.

FIG. 1 is a partial sectional view showing a state in which the centering jig of the present invention is fitted to a molding die. The lower mold including the lower mold 20 and the lower mold holder 19 is provided with an annular cavity 27 into which the resin is injected, and the lower mold has a concave region 28 surrounded by the outer peripheral side wall of the cavity 27.
Reference numeral 30 denotes a centering jig having a positioning pattern 31 at the center thereof which is equal to the positioning pattern at the center of the wafer.
Are formed. The outer diameter of the jig 30 is the concave area 2
8 has a size corresponding to the inner circumference thereof and can be fitted.

Next, an example of a method of centering the molding die in the case of changing the mold will be described.

First, the hole of the lower die of the molding die on which the centering jig is set is fitted into the molding die guide 25 projecting from the center of the lower heater block 18. Guide 25 in this case
Is worn, and even if there is play between the heater block and the lower mold, if the degree is within the range that can be corrected by the alignment unit described later, the lower mold is removed while being eccentrically fitted. Although not shown, the heater block may be fixed with screws, for example. At this time, the positioning pattern 31 of the jig 30 indicates the center position of the lower concave area 28.

Next, the jig is chucked by a vacuum chuck attached to the transfer unit 4 and picked up from the lower mold, and conveyed from the molding unit 5 to the positioning unit 9 in the reverse of the routine operation, and the X- It is mounted on a Y table (semiconductor mounting table) 7. The transport is reversible because the transport unit 4 can reciprocate between the alignment unit 9 and the molding unit 5 at a constant transport pitch.

Next, the jig positioning pattern 31 is detected by the automatic recognition device 8. The automatic recognition device 8 has a television camera whose optical axis is perpendicular to the XY table and image processing means built in a computer, and detects the positioning pattern 31. The data of the detection result is stored in the memory of the device 8 and becomes a positioning reference pattern of the positioning unit 9 in a subsequent operation.

Next, the centering jig 30 is removed, and a routine operation is started. That is, the wafer 1 to be processed is transported from the wafer supply unit 3 by the vacuum chuck attached to the transport unit 4 and is placed on the XY table 7. The automatic recognition device 8 detects a positioning pattern provided at the center of the wafer 1, compares the detection result with the detection result of the positioning reference pattern, obtains a shift amount in the X and Y directions, and obtains an XY table. Is driven to correct the shift amount. That is, the positioning pattern of the wafer is matched with the positioning reference pattern. The above operation is automatically performed by a control unit (not shown).

Next, the wafer positioned by the transfer unit 4 is transferred to the forming unit, and is placed in the concave area of the lower die. Since the transport unit 4 has a constant transport pitch as described above, and the displacement accompanying the transport is reversible,
The center of the lower mold concave region coincides with the center of the placed wafer.

The subsequent steps are the same as in the prior art. After lowering the upper mold and clamping the mold, resin is injected into the cavity to obtain a molded product.

According to the alignment unit and the method of centering the mold shown in the above embodiment, the following results can be obtained.

(1) The wafer can be accurately positioned with respect to the molding die without being affected by the wear of the molding die and the guide portion of the molding die, and the defective specification after resin molding can be eliminated.

(2) A centering jig having the same diameter as the concave area of the mold is used. After being fitted to the mold, it is reversely conveyed, and is located at the center of the centering jig by the automatic recognition device. The position of the positioning pattern can be obtained by coordinate numerical values, which is useful in process management.

(3) Conventionally, there is no need to measure the eccentricity of a sample in which a wafer is set on a mold and to correct the position of the mold, which is required every time the mold is replaced.

(4) The positioning time at the time of changing the mold can be shortened.

[0030]

As described above, in the present invention, since the centering jig is used, even if, for example, the centering mold guide portion is worn, it is not affected by this.
It has been possible to provide a positioning unit and a method of centering the mold, which can easily detect the center position of the mold, guarantee the dimensional accuracy of the molded product, improve the yield, and reduce the incidental work.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing a state where a centering jig of the present invention is fitted to a molding die.

FIG. 2 is a plan view showing an outline of a configuration of a semiconductor manufacturing apparatus used for carrying out the present invention and a conventional technique.

FIG. 3 is a partial sectional view of a molding unit of the semiconductor manufacturing apparatus shown in FIG.

FIG. 4 is a partially crushed perspective view of a semiconductor component during a processing step handled by the present invention and the prior art.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor substrate (wafer) 2 resin 3 wafer supply unit 4 transfer unit 5 molding unit 6 gantry 7 XY table 8 automatic recognition device 9 positioning unit 16 upper die 18 lower die heater block 19 lower die holder 20 lower die 25 Mold guide 27 Cavity 28 Lower mold concave area 30 Centering jig 31 Centering jig positioning pattern

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Jin Tateishi 25-1, Ekimae Honcho, Kawasaki-ku, Kawasaki-shi, Kanagawa In-house Toshiba Microelectronics Corporation (56) References JP-A-2-113526 (JP, A) JP-A Heisei JP-A-4-14875 (JP, A) JP-A-5-47616 (JP, A) JP-A-4-48639 (JP, A) JP-A-2-292842 (JP, A) JP-A-63-141370 (JP, A) A) (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 29/74 H01L 21/02 H01L 21/56 H01L 21/68

Claims (1)

(57) [Claims] 1. A method of centering a molding die having a cavity having the same shape as the annular region of a semiconductor manufacturing apparatus for molding a resin in an annular region surrounding a peripheral portion of a semiconductor substrate,
(A) a positioning unit that has a semiconductor substrate mounting table for mounting a semiconductor substrate provided with a positioning pattern and aligns the positioning pattern with a positioning reference pattern; and (b) an upper die and a lower die, A semiconductor comprising: a molding unit having a molding die provided with a concave area surrounded by an outer peripheral side wall of the annular cavity; and (c) a transport unit that reciprocates between the alignment unit and the molding unit at a constant transport pitch. Using a manufacturing apparatus, a centering jig fitted to the concave area of the lower mold and provided with a positioning pattern on the main surface is prepared, and a centering jig is provided in the concave area of the lower mold mounted on the molding unit. After the fixtures are fitted, the centering jig is picked up and transported by the transport unit, and the positioning pattern on the jig when placed on the semiconductor mounting table of the alignment unit is moved to the position of the alignment unit. Centering method and alignment unit, wherein the mold to be decided reference pattern.