JP2016004830A - Manufacturing method of semiconductor chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor chip capable of suppressing generation of a corrosive gas at a plasma etching step after grinding.SOLUTION: A method of manufacturing a semiconductor chip includes a cutting groove formation step, a rear face grinding step, a cleaning step, a drying step, and a plasma etching step. The cutting groove formation step forms a cutting groove having a depth at least corresponding to a thickness of a semiconductor chip DT, on a surface of a semiconductor wafer. The rear face grinding step grinds a rear face of the semiconductor wafer while supplying grinding water to expose the cutting groove. The cleaning step cleans a rear face DTR side of the semiconductor chip DT by cleaning water CW in a state separated into individual semiconductor chips DT by the exposure of the cutting groove. The drying step dries and removes moisture remaining between the individual chips by heating, vacuum, or heated vacuum. The plasma etching step performs plasma etching of the rear face DTR of the semiconductor chip DT.

Description

  The present invention relates to a semiconductor chip manufacturing method for manufacturing a semiconductor chip by dividing a semiconductor wafer.

  Along with thinning and miniaturization of the semiconductor chip, for the purpose of improving the bending strength of the semiconductor chip, the semiconductor wafer is divided into semiconductor chips by so-called tip dicing, and then the cutting strain layer and the grinding strain layer are removed by plasma etching, A process for improving the bending strength of a semiconductor chip has been proposed (see Patent Document 1).

JP 2003-173987 A

  Although the process disclosed in Patent Document 1 can improve the bending strength of the semiconductor chip by plasma etching, the following new problem has occurred. In other words, the cutting groove width is narrowed (several tens of μm) due to the demand of narrow streets in the pre-dicing, and the grinding water used in the grinding process enters the cutting groove, and the cleaning and drying process after grinding. Even after spinner drying, it remains almost.

In the process disclosed in Patent Document 1, a plasma etching process is directly performed on a semiconductor wafer in which grinding water remains in the cutting groove. The remaining grinding water reacts with the etching gas (for example, SF ₆ ) to generate a large amount of corrosive gas such as HF gas, which is highly corrosive, and the piping of the plasma etching apparatus corrodes and the pump frequently breaks down. A new problem has occurred.

  The present invention has been considered in view of the above problems, and an object thereof is to provide a method of manufacturing a semiconductor chip that can suppress the generation of corrosive gas in the plasma etching process.

  In order to solve the above-described problems and achieve the object, a semiconductor chip manufacturing method of the present invention is a semiconductor in which a semiconductor wafer partitioned by streets and having a plurality of semiconductor chips formed on the surface is separated into individual semiconductor chips. A chip manufacturing method, wherein a cutting groove forming step of forming a cutting groove having a depth corresponding to at least the thickness of the semiconductor chip on the surface of the semiconductor wafer, and a protective member on the surface of the semiconductor wafer on which the cutting groove is formed A back surface grinding step in which the protective member is placed on a chuck table of a grinding apparatus, and the back surface of the semiconductor wafer is ground while supplying grinding water to expose the cutting grooves, A cleaning step of cleaning the back surface side of the semiconductor chip with cleaning water in a state where the semiconductor chip is separated by the expression of the cutting groove, and the protective member after performing the cleaning step After a plurality of pasted semiconductor chips are inserted into a drying apparatus, and a drying process for drying and removing moisture remaining between individual chips by heating, vacuum, or heating vacuum, and after performing the drying process And a plasma etching step of plasma etching the back surface of the semiconductor chip.

  In the present invention, since the drying step of drying the semiconductor chip by heating vacuum drying is inserted between the cleaning step and the plasma etching step, the cleaning water remaining between the plurality of chips is removed in the cleaning step after the back surface grinding step. It can be completely removed, and the generation of corrosive gas can be suppressed in the subsequent plasma etching process.

FIG. 1 is a perspective view showing a semiconductor wafer to which a semiconductor chip manufacturing method according to an embodiment is applied. FIG. 2 is a diagram illustrating an outline of a cutting groove forming process of the semiconductor chip manufacturing method according to the embodiment. FIG. 3 is a diagram illustrating an outline of a back surface grinding step of the semiconductor chip manufacturing method according to the embodiment. FIG. 4 is a diagram illustrating an outline of a cleaning process of the semiconductor chip manufacturing method according to the embodiment. FIG. 5 is a cross-sectional view showing the main parts of the semiconductor wafer and the like after the cleaning step of the semiconductor chip manufacturing method according to the embodiment. FIG. 6 is a diagram illustrating an outline of a drying process of the semiconductor chip manufacturing method according to the embodiment. FIG. 7 is a plan view illustrating an outline of a plasma etching process of the semiconductor chip manufacturing method according to the embodiment. FIG. 8 is a diagram illustrating an outline of a plasma etching process of the semiconductor chip manufacturing method according to the embodiment.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the structures described below can be combined as appropriate. Various omissions, substitutions, or changes in the configuration can be made without departing from the scope of the present invention.

Embodiment
A method of manufacturing a semiconductor chip according to the embodiment will be described with reference to FIGS. FIG. 1 is a perspective view showing a semiconductor wafer subjected to a semiconductor chip manufacturing method according to the embodiment, FIG. 2 is a diagram showing an outline of a cutting groove forming process of the semiconductor chip manufacturing method according to the embodiment, and FIG. FIG. 4 is a diagram illustrating an outline of a back surface grinding process of the semiconductor chip manufacturing method according to the embodiment, FIG. 4 is a diagram illustrating an overview of a cleaning process of the semiconductor chip manufacturing method according to the embodiment, and FIG. Sectional drawing which shows principal parts, such as a semiconductor wafer after the washing | cleaning process of the manufacturing method of the semiconductor chip which concerns, FIG. 6 is a figure which shows the outline | summary of the drying process of the manufacturing method of the semiconductor chip which concerns on embodiment, FIG. FIG. 8 is a diagram showing an outline of the plasma etching process of the semiconductor chip manufacturing method according to the embodiment.

  The semiconductor chip manufacturing method according to the embodiment (hereinafter simply referred to as a manufacturing method) performs so-called DBG processing on the semiconductor wafer W shown in FIG. 1, and each semiconductor chip DT (shown in FIG. 4 and the like) is subjected to the semiconductor wafer W. It is the manufacturing method isolate | separated into.

  Note that the semiconductor wafer W as a processing target divided into individual semiconductor chips DT by the manufacturing method according to the embodiment is a disk-shaped semiconductor wafer using silicon or the like as a base material in the present embodiment. As shown in FIG. 1, the semiconductor wafer W is partitioned by streets L, and a plurality of semiconductor chips DT are formed on the surface WS. In the semiconductor wafer W, after a cutting groove CS (shown in FIG. 2 and the like) is formed in the street L, the back surface WR side of the back surface of the front surface WS is ground and thinned, and separated into semiconductor chips DT. For example, in the embodiment, the finished thickness T (shown in FIG. 3) of the semiconductor chip DT is 40 μm, the size of the semiconductor chip DT is 0.2 mm × 0.2 mm, and the width of the cutting groove CS is 15 μm. . 1 to 8, the size of the semiconductor chip DT is shown larger than the actual size for easy understanding.

  The manufacturing method according to the embodiment includes a cutting groove forming process, a back grinding process, a cleaning process, a drying process, and a plasma etching process.

  In the cutting groove forming step, as shown in FIG. 2, a dicing tape TD is attached to the back surface WR of the semiconductor wafer W, and the back surface WR of the semiconductor wafer W is attached to the chuck table 11 of the cutting apparatus 10 via the dicing tape TD. Hold by suction. Then, the street L of the semiconductor wafer W is cut by the cutting blade 12 while the chuck table 11 and the cutting blade 12 of the cutting apparatus 10 are relatively moved along the street L. Then, a cutting groove CS deeper than the finished thickness T of the semiconductor chip DT is formed in the street L of the semiconductor wafer W. In the present invention, the depth of the cutting groove CS may be made equal to the finished thickness T of the semiconductor chip DT, and the depth of the cutting groove CS may be made deeper than the finished thickness T of the semiconductor chip DT. . As described above, in the cutting groove forming step of the present invention, the cutting groove CS having a depth corresponding to at least the thickness T of the semiconductor chip DT is formed on the surface WS of the semiconductor wafer W. And it progresses to a back surface grinding process.

  In the back surface grinding step, the protective member TG is attached to the front surface WS of the semiconductor wafer W in which the cutting grooves CS are formed, and the dicing tape TD is peeled from the back surface WR. Then, as shown in FIG. 3, the surface WS of the semiconductor wafer W is placed on the chuck table 21 of the grinding apparatus 20 with the protective member TG facing down, and is sucked and held on the chuck table 21. Thereafter, a grinding wheel 22 (corresponding to a grinding means) that rotates around the axis of the grinding device 20 is positioned on the chuck table 21 that rotates around the axis. Then, while supplying grinding water to the back surface WR of the semiconductor wafer W through the nozzles 23 in the grinding wheel 22, the grinding wheel 22 is gradually lowered and fed to the back surface WR of the semiconductor wafer W by grinding.

  The back surface WR of the semiconductor wafer W is ground and thinned by the grinding wheel 22, and the cutting groove CS is exposed to the back surface WR side, so that the semiconductor wafer W is separated into individual semiconductor chips DT. When the thickness of the semiconductor chip DT reaches the finished thickness T, the grinding wheel 22 is separated from the chuck table 21, and the semiconductor wafer W on the chuck table 21, that is, the suction holding of the semiconductor chip DT is released. Then, the process proceeds to the cleaning process. When the semiconductor wafer W is separated into individual semiconductor chips DT, the front surface WS of the semiconductor wafer W becomes the front surface DTS of the semiconductor chip DT, and the back surface WR becomes the back surface DTR of the semiconductor chip DT.

  In the cleaning process, the surface DTS of the semiconductor chip DT is removed from the surface DTS of the semiconductor chip DT via the protective member TG as shown in FIG. And sucked and held on the chuck table 31. Then, the chuck table 31 is rotated around the axis, and the cleaning water CW is supplied from the cleaning water supply unit 32 of the cleaning device 30 to the back surface DTR side of the semiconductor chip DT, thereby cleaning the back surface DTR side of the semiconductor chip DT. Wash with water CW.

  When the cleaning of the back surface DTR of the semiconductor chip DT is completed, the process proceeds to a drying process. Since the width of the cutting groove CS, that is, the interval between the semiconductor chips DT is a very small value such as 15 μm, for example, after the cleaning process, as shown in FIG. Cleaning water CW remains between the semiconductor chips DT.

  In the drying process, after the cleaning process is performed, the plurality of semiconductor chips DT adhered to the protective member TG are inserted into the drying chamber 41 of the drying device 40. Then, as shown in FIG. 6, the surface DTS of the semiconductor chip DT is placed on the holding table 42 of the drying device 40 via the protective member TG and is held on the holding table 42. Then, the gas in the drying chamber 41 is discharged to the outside of the drying chamber 41 by the vacuum pump 43 to lower the pressure in the drying chamber 41 below atmospheric pressure, and the semiconductor wafer W, that is, the semiconductor chip DT is heated by the gas heater 44. . Then, moisture (such as cleaning water CW) remaining between the individual semiconductor chips DT evaporates and the semiconductor chip DT is dried.

  The temperature of the gas by the gas heater 44 is determined from the heat resistance temperature of the protection member TG, and is set between 40 ° C. and 60 ° C., for example, when the heat resistance temperature of the protection member TG is 70 ° C. In the present invention, the pressure in the drying chamber 41 is preferably a pressure in the vicinity of the saturated water vapor pressure of water at the gas temperature by the gas heater 44. In this case, the semiconductor chip DT can be reliably dried. Thus, in the drying step, moisture remaining between the individual semiconductor chips DT is removed by drying by heating vacuum. When the drying is completed, the process proceeds to the plasma etching process. In the present invention, in the drying process, a heater may be incorporated in the holding table 42 to heat the semiconductor chip DT, or the semiconductor chip DT may be heated with a halogen heater.

  In the plasma etching process, after performing the drying process, as shown in FIG. 7, the plurality of semiconductor chips DT adhered to the protective member TG are inserted into the chamber 51 of the plasma etching apparatus 50. Then, as shown in FIG. 8, the surface DTS of the semiconductor chip DT is placed on the holding unit 52 of the plasma etching apparatus 50 via the protective member TG, and the suction pump 53 connected to the holding unit 52 is driven and held. The semiconductor chip DT is sucked and held in the part 52. The gas in the chamber 51 is sucked by the suction pump 54 and discharged out of the plasma etching apparatus 50 through the filter 55, and the inside of the chamber 51 is evacuated.

Thereafter, an etching gas such as a rare fluorine-based gas (SF ₆ + He) is supplied into the chamber 51 from the etching gas storage unit 57 by the pump 56, and the high frequency power source and the tuner 58 are provided with the holding unit 52. A high frequency voltage is supplied to the high frequency electrode 59b where the electrode 59a and the back surface DTR of the semiconductor chip DT face each other. At this time, the holding part 52 is cooled by the cooling water circulated by the cooling water circulator 60. Then, the back surface DTR of the semiconductor chip DT is subjected to plasma etching using plasma, and the grinding strain layer generated on the back surface DTR of the semiconductor chip DT and the cutting strain layer generated on the side surface of the semiconductor chip DT are removed. . After the plasma etching is completed, the semiconductor chip DT is transferred to the next process.

  According to the manufacturing method according to the embodiment, since the drying process of drying the semiconductor chip DT by heating vacuum drying is inserted between the cleaning process and the plasma etching process, a plurality of semiconductors are used in the cleaning process after the back surface grinding process. It is possible to completely remove the cleaning water CW remaining between the chips DT. Therefore, generation of corrosive gas can be suppressed in the plasma etching process.

  In the above-described embodiment, in the drying process, the inside of the drying chamber 41 is heated and evacuated, and the semiconductor chip DT is dried by heating vacuum. However, in the present invention, the inside of the drying chamber 41 is maintained at atmospheric pressure. A vacuum (lowering the pressure below atmospheric pressure) may be used without heating or heating the inside of the drying chamber 41. In short, in the present invention, in the drying process, the cleaning water CW remaining between the individual semiconductor chips DT may be dried and removed by heating, vacuum, or heating vacuum.

  The present invention is not limited to the above embodiment. That is, various modifications can be made without departing from the scope of the present invention.

20 Grinding device 21 Chuck table 40 Drying device CW Washing water DT Semiconductor chip DTR Back surface L Street T Thickness TG Protective member W Semiconductor wafer WS surface WR Back surface CS Cutting groove

Claims (1)

A semiconductor chip manufacturing method for separating a semiconductor wafer partitioned by streets and having a plurality of semiconductor chips formed on a surface into individual semiconductor chips,
A cutting groove forming step of forming a cutting groove having a depth corresponding to at least the thickness of the semiconductor chip on the surface of the semiconductor wafer;
A protective member is attached to the surface of the semiconductor wafer on which the cutting grooves are formed, and the protective member is placed on a chuck table of a grinding apparatus with the protective member down, and the back surface of the semiconductor wafer is ground while supplying grinding water. A back grinding process for exposing the cutting groove;
A cleaning step of cleaning the back side of the semiconductor chip with cleaning water in a state where the semiconductor chip is separated into individual semiconductor chips by the exposure of the cutting grooves,
After carrying out the cleaning step, a plurality of the semiconductor chips attached to the protective member are inserted into a drying apparatus, and moisture remaining between the individual chips is removed by heating, vacuum, or heating vacuum. A drying process,
A plasma etching step of performing plasma etching on the back surface of the semiconductor chip after the drying step;
A method for manufacturing a semiconductor chip comprising:

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