JP2017162931A - Manufacturing method for device chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent damage to a device chip by improving transverse intensity of a device chip.SOLUTION: A manufacturing method for a device chip, which uses a plasma etching device (1) with a buffer plate (45) partitioning a decompression chamber (50) and having a narrow hole through which etching gas is passed, comprises: an ion removal step in which the etching gas made into plasma is passed through a buffer plate by means of a current of air in the decompression chamber and ions (21) are removed from the etching gas; and an etching step in which a device chip (80) is caused to supply the etching gas formed from a radical as its main constituent as a result of removing ions by its having been passed through the buffer plate by means of a current of air in the decompression chamber, and a side face (86) of the device chip is plasma etched.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a device chip manufacturing method for plasma etching a device chip.

  In the semiconductor device manufacturing process, the wafer is partitioned by the division line, and the device chip is manufactured by dividing the wafer along the division line. As a wafer dividing method, there are a method of dividing with a cutting blade (see, for example, Patent Document 1), a method of dividing by ablation processing by irradiating a laser beam, and a method of dividing a modified layer formed on a wafer with a laser beam as a starting point. It is known (see, for example, Patent Document 2).

  In the method of dividing using a cutting blade, the wafer is cut along a planned dividing line with a high-speed rotating cutting blade to cut the wafer. In the method of dividing by ablation, the wafer is irradiated with a laser beam having an absorptive wavelength, and the wafer is broken along the planned dividing line. In the method of dividing the modified layer from the starting point, the wafer is irradiated with a laser beam having a wavelength having transparency, and the modified layer is continuously formed along the line to be divided. To break the wafer.

JP2015-159241A JP 2006-018881 A

  By the way, unevenness is generated on the side surface of the device chip into which the wafer is divided, and the bending strength of the device chip is lowered from this unevenness, and the device chip may be damaged. Therefore, in order to improve the bending strength of the device chip, a method of removing irregularities from the device chip by plasma etching can be considered. However, when the plasma etching is performed in a state where the wafer is divided into chips, there is a problem that the side surface of the device chip is not etched well and the unevenness is difficult to remove.

  The present invention has been made in view of this point, and an object of the present invention is to provide a device chip manufacturing method that can improve the bending strength of the device chip and prevent the device chip from being damaged.

  The device chip manufacturing method of the present invention is a device chip manufacturing method for increasing the bending strength of a device chip by plasma etching the side surface of the device chip. The plasma etching apparatus decompresses the decompression chamber and the decompression chamber. Etching by partitioning the decompression chamber between the exhaust means, the etching gas supply port for supplying the etching gas from above the decompression chamber, the holding table for holding the work below the decompression chamber, and the etching gas supply port and the holding table A buffer plate having pores through which gas is allowed to pass, and a plurality of device chips divided by a device dividing line are arranged with a gap, and one side of the device chip is attached to an adhesive tape The workpiece preparation process for preparing the workpiece and the adhesive tape side of the workpiece prepared in the workpiece preparation process The workpiece is held in the holding table, the plasma generation step is performed by supplying high-frequency power to the etching gas supplied from the etching gas supply port, and the etching gas is converted into plasma so as to include radicals, and the plasma generation step is performed to generate plasma. An ion removal step of removing the ions from the etching gas by passing the buffer plate with an airflow in the decompression chamber from the etching gas supply port to the holding table and removing ions from the etching gas, and ions are removed by passing through the buffer plate with an airflow in the decompression chamber. An etching step of supplying a main etching gas to the device chip and performing plasma etching on a side surface of the device chip.

  According to this configuration, the plasmaized etching gas passes through the buffer plate, so that ions are removed and the ratio of radicals increases. Unlike ions, radicals are carried toward the device chip in an air current without being affected by high-frequency power. That is, radicals do not fall down like ions, but fall while drifting in the decompression chamber. When radicals enter between the device chips, the side surfaces of the device chips are etched and the irregularities are removed. As described above, it is possible to uniformly etch the side surface of the device chip mainly using radicals, and to prevent damage to the device chip due to unevenness. That is, the bending strength of the device chip can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the bending strength of a device chip can be improved and damage to a device chip can be prevented.

It is a schematic diagram of the workpiece | work which concerns on this Embodiment. It is explanatory drawing which shows a mode that the workpiece | work which concerns on a comparative example is etched. 1 is an overall schematic diagram of a plasma etching apparatus according to an embodiment. It is explanatory drawing which shows the etching method of the device chip concerning this Embodiment. It is explanatory drawing which shows the manufacturing method of the device chip concerning this Embodiment. It is explanatory drawing which shows the manufacturing method of the device chip concerning this Embodiment. It is the whole plasma etching apparatus schematic diagram concerning a modification.

  Hereinafter, a method for manufacturing a device chip according to the present embodiment will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram of a workpiece according to the present embodiment. The work W is configured by adhering an adhesive tape T to one surface of a plurality of device chips 80. The device chip 80 is obtained by dividing the device wafer divided by the planned division line along the planned division line, and is arranged on the adhesive tape T with a gap. The workpiece W is carried into the plasma etching apparatus (see FIG. 3) while being supported by the ring frame F via the adhesive tape T.

  By being divided by cutting with a cutting blade or the like, fine unevenness 91 is generated on the side surface 86 of each device chip 80. In some cases, the bending strength is lowered from the unevenness 91 and the device chip 80 is damaged. In order to prevent damage to the device chip 80, a method of removing the unevenness 91 by plasma etching is conceivable. However, since normal plasma etching proceeds mainly with ions, there is a problem that the upper surface 87 side of the device chip 80 is easily etched and the side surface 86 of the device chip 80 is difficult to etch.

  FIG. 2 is an explanatory diagram illustrating a state in which the workpiece according to the comparative example is etched. In the plasma etching apparatus, the device chip 80 is etched by supplying high-frequency power to turn the etching gas into plasma, generating radicals 22 and ions 21.

  When the high frequency power is supplied, the ions 21 contained in the etching gas are attracted in the vertical direction (see arrows) with respect to the device chip 80 by the potential. In this case, since the ions 21 are attracted directly under the potential, the ions 21 easily collide with the upper surface 87 side of the device chip 80, and only the upper surface 87 side of the device chip 80 is etched. On the other hand, the radical 22 contained in the etching gas falls on the device chip 80 without being affected by the high frequency power. In this case, the radicals 22 can penetrate into the space between the device chips 80 and etch the side surfaces 86 of the device chips 80. However, since the radicals 22 are not attracted to the device chips 80 by the potential, the etching rate is the same as that of the ions 21. It is slower than that.

  In this case, since the etching is performed mainly with the ions 21, the upper side of the side surface 86 of the device chip 80 is easily etched, and it is difficult to etch toward the lower side of the side surface 86 of the device chip 80. For this reason, the device chip 80 is etched so that the side face 86 is inclined. Therefore, the unevenness 91 on the side surface 86 of the device chip 80 is also difficult to be etched toward the lower side of the side surface 86, and the unevenness 91 formed on the lower side of the side surface 86 remains.

  In the present embodiment, plasmaized etching gas is passed through a buffer plate, which will be described later, ions 21 are removed from the etching gas, and etching is performed mainly with radicals 22. Thereby, etching on the upper surface 87 side of the device chip 80 is suppressed, and the side surface 86 of the device chip 80 is effectively etched.

  Hereinafter, a plasma etching apparatus used in a device chip manufacturing method according to the present embodiment will be described with reference to the accompanying drawings. FIG. 3 is an overall schematic diagram of the plasma etching apparatus according to the present embodiment.

  The decompression chamber 50 of the chamber 30 of the plasma etching apparatus 1 is vertically divided by a buffer plate 45 and includes an upper decompression chamber 31 and a lower decompression chamber 36. A large number of pores 46 are formed in the buffer plate 45, and the upper decompression chamber 31 and the lower decompression chamber 36 communicate with each other through the pores 46.

An etching gas supply port 33 for supplying an etching gas into the decompression chamber 50 is formed on the upper wall 32 of the chamber 30, and the etching gas supply port 33 is connected to an etching gas supply source 51. As an etching gas, a fluorine-based gas in which helium gas or the like is contained in a fluorine-containing gas containing fluorine such as sulfur hexafluoride (SF ₆ ), tetrafluoromethane (CF ₄ ), nitrogen trifluoride (NF ₃ ), or the like. Plasma gas is used. An annular coil 35 is wound around the side wall 34 a above the buffer plate 45 of the chamber 30, and high frequency power is supplied to the coil 35 from a high frequency power supply 55.

  On the side wall 34b below the buffer plate 45 of the chamber 30, a loading / unloading port 38 for loading and unloading the workpiece W in which one side of the device chip 80 is adhered to the adhesive tape T is formed. An open / close door 41 that opens and closes the loading / unloading port 38 is attached to the outer wall surface of the side wall 34b. The opening / closing door 41 is connected to the upper end of the cylinder rod of the cylinder 42, and the loading / unloading port 38 is opened / closed by the cylinder 42 moving the opening / closing door 41 along the outer wall surface. When the loading / unloading port 38 is opened, the inside of the decompression chamber 50 is opened to the outside, and when the loading / unloading port 38 is closed, the inside of the decompression chamber 50 is sealed.

  A holding table 39 that holds the workpiece W is disposed in the lower decompression chamber 36. An upper surface 87 (see FIG. 1) of the workpiece W is covered with a resist film 82 (see FIG. 1). The holding table 39 holds the adhesive tape T side of the workpiece W.

  An exhaust port 52 is formed below the holding table 39, and an exhaust unit 53 that decompresses the decompression chamber 50 is connected to the exhaust port 52 via an exhaust valve (not shown). By exhausting air and reaction gas from the decompression chamber 50 to the exhaust port 52 by the exhaust means 53, the decompression chamber 50 is decompressed and an air flow is generated in the decompression chamber 50.

  The coil 35, the buffer plate 45, and the holding table 39 are grounded. When high frequency power is supplied to the coil 35 from the high frequency power supply 55, the etching gas in the upper decompression chamber 31 is turned into plasma, and radicals 22 and ions 21 (see FIG. 4) are generated in the upper decompression chamber 31.

  Next, a method for etching a device chip according to the present embodiment will be described. FIG. 4 is an explanatory view showing a device chip etching method according to the present embodiment.

  The buffer plate 45 is a plate-like member having conductivity, and a large number of pores 46 penetrating the front and back are formed. The etching gas is turned into plasma when high frequency power is supplied from the high frequency power supply 55 (see FIG. 3) to the coil 35 (see FIG. 3), and radicals 22 and ions 21 are generated. The plasmaized etching gas flows through the pores 46 of the buffer plate 45 and flows into the lower decompression chamber 36 by the airflow in the decompression chamber 50. At this time, the ions 21 in the etching gas are gasified by colliding with each other in the pores 46 of the buffer plate 45.

  The air flow is adjusted by exhausting gas from the outlet 52 by the exhaust means 53. When the gas in the decompression chamber 50 is exhausted from the discharge port 52 formed below the holding table 39 by the exhaust means 53, the gas passes through the buffer plate 45 from the upper decompression chamber 31 and passes through the buffer plate 45 to the discharge port 52. A flowing airflow is generated. By reducing the amount of gas exhausted from the exhaust port 52 to slow down the air flow and lengthening the passage time of the ions 21 in the pores 46, the ions 21 can easily react with each other.

  The radicals 22 and some of the ions 21 that have not been gasified pass directly through the pores 46 and etch the device chip 80 in the lower decompression chamber 36. The radicals 22 contained in the etching gas flowing into the lower decompression chamber 36 fall into the device chip 80 held on the holding table 39 while drifting in the lower decompression chamber 36 by the air flow. Unlike the ions 21, the radicals 22 are not affected by the high-frequency power, so that the falling direction is not limited with respect to the device chip 80. The radicals 22 that come into contact with the device chip 80 from multiple directions are likely to reach the lower side of the side surface 86 of the device chip 80 compared to those that do not hit the side surface 86 of the device chip 80 like the ions 21. The radicals 22 that have entered between the device chips 80 react with the device chips 80 to etch the side surfaces 86, and the unevenness 91 can be removed by isotropic etching.

  The radicals 22 and ions 21 that have fallen to the outside of the workpiece W are exhausted from the discharge port 52 by riding on an airflow toward the discharge port 52. The reaction rate between the radical 22 and the device chip 80 is adjusted by adjusting the amount of gas exhausted from the exhaust port 52 by the exhaust means 53. The radicals 22 falling on the device chip 80 can be increased by increasing the amount of gas exhausted from the exhaust port 52 to speed up the airflow.

  Further, since the ions 21 are gasified by the buffer plate 45, the ratio of the radicals 22 is large and the ratio of the ions 21 is small in the etching gas that passes through the buffer plate 45 and flows into the lower decompression chamber 36. . Thereby, the etching by the ions 21 can be suppressed, and the etching by the radicals 22 can be mainly performed. Therefore, etching on the upper surface 87 side of the device chip 80 can be suppressed, and the side surface 86 of the device chip 80 can be etched uniformly, and damage to the device chip 80 caused by the unevenness 91 on the side surface 86 can be prevented. it can. That is, the bending strength of the device chip 80 can be improved.

  The region where the plurality of pores 46 are formed in the buffer plate 45 is substantially the same as the region where the plurality of device chips 80 of the workpiece W are disposed from the viewpoint of efficiently dropping the radicals 22 on the workpiece W. preferable. The diameter of the pore 46 is not particularly limited, but is preferably 0.5 mm or more and 1 mm or less from the viewpoint of efficiently gasifying the ions 21 by colliding with each other in the pore 46. The pores 46 can be formed in the buffer plate 45 at equal intervals, but the portion located above the outer periphery of the work W has a higher density than the portion located near the center of the work W. It is preferably formed so as to be large (the number of holes is large). The radicals 22 that have fallen near the outer periphery of the workpiece W are easily exhausted from the exhaust port 52. However, by changing the density formed on the buffer plate 45 of the pores 46, a large amount of radicals 22 also fall near the outer periphery of the workpiece W. Thus, the number of radicals 22 that react with the workpiece W can be increased. For this reason, the center and outer peripheral side of the workpiece | work W can be etched uniformly.

  Next, a method for manufacturing a device chip according to the present embodiment will be described. 5 and 6 are explanatory diagrams showing a method for manufacturing a device chip according to the present embodiment.

  First, the work preparation process will be described. As shown in FIG. 5A, an adhesive tape T is attached to one surface (lower surface) of the device chip 80 of the workpiece W, and the workpiece W is supported by the ring frame F via the adhesive tape T. A resist film 82 is formed on the upper surface 87 on which the device 81 of the workpiece W is formed.

  Next, the work holding process will be described. As shown in FIG. 5B, the workpiece W is carried in from the loading / unloading port 38 of the plasma etching apparatus 1 while being supported by the ring frame F via the adhesive tape T. Then, the adhesive tape T side of the workpiece W is held on the holding table 39.

  Next, the plasma generation process will be described. As shown in FIG. 5C, the etching gas is supplied from the etching gas supply port 33 to the upper decompression chamber 31. When high frequency power is supplied from the high frequency power supply 55 to the coil 35, the etching gas in the upper decompression chamber 31 is turned into plasma, and radicals 22 and ions 21 are generated.

  Next, the ion removal process will be described. As shown in FIG. 6A, the etching gas converted into plasma in the upper decompression chamber 31 is allowed to pass through the buffer plate 45 with an air flow in the decompression chamber 50 from the etching gas supply port 33 toward the holding table 39. The ions 21 in the etching gas are gasified by colliding with each other in the pores 46 of the buffer plate 45.

  Next, the etching process will be described. As shown in FIG. 6B, the radicals 22 and some ions 21 pass through the pores 46 and etch the device chip 80 in the lower decompression chamber 36. The etching gas that has passed through the buffer plate 45 is supplied to the device chip 80 by the air flow in the decompression chamber 50. The radicals 22 fall into the device chip 80 while drifting in the lower decompression chamber 36 by the airflow. Since the radicals 22 come into contact with the device chip 80 from multiple directions, the radicals 22 can easily reach the lower side of the side surface 86 of the device chip 80 as compared with those that do not easily hit the side surface 86 of the device chip 80 like the ions 21. The radicals 22 that have entered between the device chips 80 react with the device chips 80 to perform isotropic etching of the side surfaces 86, thereby removing the irregularities 91. The reaction between the radical 22 and the device chip 80 can be adjusted by adjusting the air flow with the exhaust means 53 (see FIG. 3).

  Since the ions 21 are removed from the etching gas converted into plasma in the ion removal step, the ratio of the radicals 22 is large and the ratio of the ions 21 is small in the etching gas that passes through the buffer plate 45 and flows into the lower decompression chamber 36. . Since etching by radicals 22 can be mainly performed, etching on the upper surface 87 side of the device chip 80 can be suppressed, and the side surface 86 of the device chip 80 can be uniformly etched. It is possible to prevent the device chip 80 from being damaged starting from the above.

  In the present embodiment, the etching gas that has passed through the buffer plate 45 is supplied to the device chip 80 by the airflow in the decompression chamber 50 without supplying high-frequency power to the holding table 39. As a result, even if some of the ions 21 that have not been gasified by the buffer plate 45 pass through the buffer plate and flow into the lower decompression chamber 36, they are not attracted to the device chip 80 by the potential. For this reason, the etching rate of the device chip 80 is not increased by the ions 21, and the etching on the upper surface 87 side of the device chip 80 can be suppressed.

  As described above, the plasmaized etching gas passes through the buffer plate 45, whereby the ions 21 are removed and the ratio of the radicals 22 increases. Unlike the ions 21, the radicals 22 are carried toward the device chip 80 in an air current without being affected by high-frequency power. That is, the radical 22 does not fall directly below the ion 21 but falls while drifting in the decompression chamber 50. When the radical 22 enters between the device chips 80, the side surfaces 86 of the device chip 80 are etched, and the unevenness 91 is removed. As described above, it is possible to uniformly etch the side surface 86 of the device chip 80 with the radical 22 as a main component, thereby preventing the device chip 80 from being damaged due to the unevenness 91. That is, the bending strength of the device chip 80 can be improved.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the above-described embodiment, the coil 35 is wound around the side wall 34a above the buffer plate 45 of the chamber 30, but the present invention is not limited to this configuration. FIG. 7 is an overall schematic diagram of a plasma etching apparatus according to a modification. The plasma etching apparatus of the above embodiment and the plasma etching apparatus of FIG. 7 are different in that the coil 65 is wound around the side wall 64 of the etching gas supply port 63, but both have the same effect.

  In addition, the pores 46 of the buffer plate 45 are configured such that the portion located above the outer periphery of the workpiece W has a higher density than the portion located near the center of the workpiece W. The configuration is not limited to this. The pores 46 may be formed in the buffer plate 45 at equal intervals.

  Moreover, although the workpiece | work W was set as the structure supported by the ring frame F via the adhesive tape T, it is not limited to this structure. The workpiece W may not be supported by the ring frame F.

  Moreover, although it was set as the structure which sticks the single side | surface (lower surface) of the device chip 80 to the adhesive tape T, it is not limited to this structure. The side surface 86 may be etched by attaching the device chip 80 to the adhesive tape T with the upper surface 87 (device surface) facing down.

  As described above, the present invention has an effect of improving the bending strength of the device chip and preventing the device chip from being damaged. In particular, the present invention provides a device chip manufacturing method for plasma etching a device chip. Useful.

DESCRIPTION OF SYMBOLS 1 Plasma etching apparatus 21 Ion 22 Radical 33 Etching gas supply port 39 Holding table 45 Buffer plate 46 Pore 50 Depressurization chamber 53 Exhaust means 80 Device chip 86 (Device chip) side surface T Adhesive tape W Workpiece

Claims (1)

A device chip manufacturing method for increasing the bending strength of a device chip by plasma etching the side surface of the device chip,
The plasma etching apparatus includes: a decompression chamber; an exhaust unit that decompresses the decompression chamber; an etching gas supply port that supplies an etching gas from above the decompression chamber; and a holding table that holds a workpiece below the decompression chamber; A buffer plate having pores that partition the decompression chamber between the etching gas supply port and the holding table and allow the etching gas to pass therethrough,
A work preparing step of preparing a work in which a plurality of device chips divided by a line to be divided are arranged with a gap, and a work in which one side of the device chip is adhered to an adhesive tape is prepared,
A workpiece holding step of holding the adhesive tape side of the workpiece prepared in the workpiece preparation step on the holding table;
A plasma generation step of supplying high-frequency power to the etching gas supplied from the etching gas supply port, and converting the etching gas into a plasma containing radicals;
An ion removal step of removing ions from the etching gas by passing the buffer gas through the buffer plate with an air flow in the decompression chamber from the etching gas supply port toward the holding table through the etching gas plasmified in the plasma generation step;
An etching step of plasma-etching the side surface of the device chip by supplying an etching gas mainly passing through the buffer plate with the airflow in the decompression chamber to remove ions and mainly radicals;
A method of manufacturing a device chip including:

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