KR20240023479A - Method for processing wafer - Google Patents

Abstract

(Project) To provide a wafer processing method that can process wafers in which a passivation film is laminated on a pattern layer with good quality.
(Solution) Processing the wafer 100 on which the pattern layer 120 and the passivation film 130 covering the pattern layer 120 are formed on the surface 111 of the substrate 110 along the division line 112. The wafer processing method includes a passivation film processing step of forming a first processing groove 151 in the passivation film 130 by irradiating a laser beam with a first output along the division line 112, and forming the first processing groove. A pattern layer processing step of forming a second processing groove 152 in the pattern layer 120 by irradiating a laser beam 21 of a second output greater than the first output along 151, and forming the second processing groove 152. Following 152, there is a substrate processing step for processing the substrate 11.

Description

Wafer processing method {METHOD FOR PROCESSING WAFER}

The present invention relates to a method of processing a wafer whose pattern layer is covered with a passivation film.

A method of processing a passivation film and a pattern layer with a single laser is known (for example, see Patent Document 1).

Patent Document 1: Japanese Patent Publication No. 2018-026397

However, as the pattern layer becomes thicker, it is necessary to form processing grooves with a laser beam of greater output, and problems such as peeling or weakening of the passivation film when processed with the same output occurred.

The present invention was made in view of these problems, and its purpose is to provide a wafer processing method that can process wafers in which a passivation film is laminated on a pattern layer with good quality.

In order to solve the above-mentioned problem and achieve the purpose, the wafer processing method of the present invention is to process a wafer on which a pattern layer is formed on the surface of the substrate and a passivation film covering the pattern layer along a line scheduled to be divided. As a method,

A passivation film processing step of forming a first processing groove in the passivation film by irradiating a laser beam with a first output along the division line, and forming a second output greater than the first output along the first processing groove. A pattern layer processing step of forming a second processing groove in the pattern layer by irradiating a laser beam, and a substrate processing step of processing the substrate along the second processing groove.

In the substrate processing step, a plurality of chips may be manufactured by dividing the substrate.

The passivation film may be polyimide.

The passivation film processing step may use laser light with a pulse width in the picosecond or femtosecond range.

The first machining groove may be wider than the width of the second machining groove.

In the present invention, after processing the passivation film with a laser beam of a first output, the pattern layer is processed with a laser beam of a second output greater than the first output, thereby suppressing heat damage to the passivation film 130 and preventing peeling. The pattern layer can be processed with good quality while suppressing deterioration and damage, and a wafer with a passivation film laminated on the pattern layer can be processed with good quality.

1 is a flowchart showing the processing sequence of the wafer processing method according to Embodiment 1.
FIG. 2 is a perspective view showing a wafer to be processed in the wafer processing method according to Embodiment 1.
FIG. 3 is a cross-sectional view of the wafer of FIG. 2.
FIG. 4 is a cross-sectional view illustrating the passivation film processing step of FIG. 1.
FIG. 5 is a cross-sectional view illustrating the pattern layer processing step of FIG. 1.
FIG. 6 is a cross-sectional view illustrating the substrate processing step of FIG. 1.
FIG. 7 is a cross-sectional view illustrating the passivation film processing step of the wafer processing method according to Embodiment 2.
FIG. 8 is a cross-sectional view illustrating the passivation film processing step of the wafer processing method according to Embodiment 2.
FIG. 9 is a cross-sectional view illustrating the passivation film processing step of the wafer processing method according to Embodiment 2.
FIG. 10 is a cross-sectional view illustrating the pattern layer processing step of the wafer processing method according to Embodiment 2.
FIG. 11 is a cross-sectional view illustrating the pattern layer processing step of the wafer processing method according to Embodiment 2.
FIG. 12 is a cross-sectional view illustrating the pattern layer processing step of the wafer processing method according to Embodiment 2.

The form (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the content described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Additionally, the configurations described below can be combined appropriately. Additionally, various omissions, substitutions, or changes in the structure may be made without departing from the gist of the present invention.

[Embodiment 1]

A wafer processing method according to Embodiment 1 of the present invention will be described based on the drawings. FIG. 1 is a flowchart showing the processing sequence of the wafer processing method according to Embodiment 1. The wafer processing method according to Embodiment 1 is a method of processing a wafer 100 as described later, and as shown in FIG. 1, a passivation film processing step (1001) and a pattern layer processing step (1002) and a substrate processing step (1003).

FIG. 2 is a perspective view showing a wafer 100 that is a processing target in the wafer processing method according to Embodiment 1. FIG. 3 is a cross-sectional view of the wafer 100 of FIG. 2.

As shown in FIGS. 2 and 3, the wafer 100, which is the object of processing in the wafer processing method according to Embodiment 1, has a pattern layer 120 on the surface 111 of the substrate 110 and a pattern layer ( A passivation film 130 is formed covering 120). The substrate 110 is, for example, a disk-shaped semiconductor wafer or optical device wafer made of silicon as a base material. The base material of the substrate 110 is not limited to this in the present invention, and may be sapphire, silicon carbide (SiC), gallium arsenide, etc. As shown in FIG. 2, the substrate 110 has a chip-sized device area portion 113 formed in an area partitioned by a plurality of division lines 112 formed in a grid shape on the flat surface 111. It is done.

The wafer 100 includes a portion of each device region 113 of the substrate 110, a portion of each pattern layer 120 formed on each device region 113, and a portion of each passivation film 130. A plurality of device chips (see FIG. 2), each configured including a device, are formed.

In Embodiment 1, the pattern layer 120 is a metal pattern layer for an electronic circuit, an electrode, an inspection or evaluation element (Test Element Group, TEG), or an integrated circuit (IC). The pattern layer 120 has a thickness of 10 μm or more and 100 μm or less, and is sufficiently thicker than the passivation film 130, as shown in FIG. 3 . When the wafer 100 is divided into a plurality of device chips, the pattern layer 120 may have a thickness similar to that of the substrate 110 or may be thicker than the substrate 110 .

The passivation film 130 is a polyimide film in Embodiment 1, but the present invention is not limited to this and may be an oxide film or a nitride film. The passivation film 130 has a thickness of 2 ㎛ or more and 10 ㎛ or less, and is sufficiently thinner than the pattern layer 120. The passivation film 130 is not a temporary protective film to be removed after the substrate processing step 1003, but is a pattern layer 120 or a substrate ( It is left to protect a portion of the device area portion 113 of 110). That is, the passivation film 130 is preferably not peeled off even when the wafer 100 is divided into a plurality of device chips.

In Embodiment 1, the wafer 100 has a support member 141 attached to the back surface 114 on the back side of the surface 111 of the substrate 110, as shown in FIG. 2, and the support member 141 ), an annular frame 142 is mounted on the outer edge, but the present invention is not limited to this.

The support member 141 is made of an adhesive tape having a flexible and non-adhesive base layer and an adhesive layer laminated on the base layer and being flexible and adhesive, or a sheet made of a thermoplastic resin without an adhesive layer. do.

In the case of a non-adhesive thermoplastic resin sheet, the support member 141 is preferably a polyolefin sheet, polyethylene sheet, polypropylene sheet, or polystyrene sheet, and is attached to the frame 142 or the wafer 100 by heat compression.

The support member 141 does not need to be in the form of a sheet from the beginning, and supplies powder or liquid to the back surface 104 of the wafer 100 (back surface 114 of the substrate 110), and can be used for thermal compression, compression, or spin. It may be formed into a sheet shape that covers the back surface 104 of the wafer 100 by coating.

FIG. 4 is a cross-sectional view illustrating the passivation film processing step 1001 of FIG. 1. In the passivation film processing step 1001, as shown in FIG. 4, the laser beam 11 is irradiated with a first output along the division line 112, and the first processing groove 151 is formed on the passivation film 130. ) is the stage of forming.

In the passivation film processing step 1001, as shown in FIG. 4, the laser irradiator 10 emits a laser beam 11 having a wavelength that is absorptive to the passivation film 130 as the first output to the wafer. The wafer ( By transporting and moving 100 relative to the laser irradiator 10 along the division line 112, the passivation film 130 is laser processed (so-called) along the division line 112 with the laser beam 11. ablation processing) to remove the passivation film 130 along the division line 112 and form a first processing groove 151 with a depth that penetrates the passivation film 130 and reaches the pattern layer 120. do.

In the wafer processing method according to Embodiment 1, since the passivation film 130 is processed by irradiation of the laser beam 11, there is no need to process the passivation film 130 by lithography, so the passivation film ( 130) costs related to processing can be reduced.

FIG. 5 is a cross-sectional view illustrating the pattern layer processing step 1002 of FIG. 1. As shown in FIG. 5, the pattern layer processing step 1002 applies a laser beam 21 of a second output greater than the first output along the first processing groove 151 formed in the passivation film processing step 1001. ) is a step of forming a second processing groove 152 in the pattern layer 120.

In the pattern layer processing step 1002, as shown in FIG. 5, the laser beam 21 having a wavelength that is absorbable to the pattern layer 120 is emitted by the laser irradiator 20 at a first output greater than the first output. With output 2, the wafer 100 is irradiated by the laser irradiator 20 by a drive source (not shown) while irradiating the pattern layer 120 exposed on the bottom surface of the first processing groove 151 formed on the wafer 100. By relatively transporting and moving along the extending direction of the first processing groove 151, the pattern layer 120 is laser processed along the extending direction of the first processing groove 151 with the laser beam 21. (So-called ablation processing), the pattern layer 120 is removed along the extending direction of the first processing groove 151, and the pattern layer 120 is further penetrated from the bottom surface of the first processing groove 151. Thus, a second processing groove 152 is formed whose depth reaches the surface 111 of the substrate 110. Additionally, the direction in which the first processing groove 151 extends is along the division line 112 .

Here, the passivation film 130 processed in the passivation film processing step 1001 is a polyimide film, an oxide film, or a nitride film, and is thinner than the pattern layer 120, so a second processing groove 152 is formed in the pattern layer 120. ), thermal damage is likely to occur and peeling, deterioration, and damage occur when a laser beam with an average power capable of forming the pattern layer 120 is formed (pattern layer 120 It is necessary to process it by irradiation of a laser beam with an average power smaller than the average power suitable for the division of ).

Meanwhile, the pattern layer 120 processed in the pattern layer processing step 1002 includes a wiring structure including a metal pattern layer such as an electronic circuit, an electrode, an inspection or evaluation element, an integrated circuit, and a passivation film ( 130), since the second processing groove 152 cannot be formed by irradiation of a laser beam with an average power lower than the average power suitable for forming the first processing groove 151 (division of the passivation film 130). , it is necessary to process it by irradiation of a laser beam with an average output greater than the average output suitable for dividing the passivation film 130. For this reason, the wafer processing method according to Embodiment 1 includes two steps: a passivation film processing step 1001 for processing the passivation film 130 and a pattern layer processing step 1002 for processing the pattern layer 120. Provided, by changing the laser beam irradiated in two stages, heat damage to the passivation film 130 is suppressed, peeling, deterioration, and damage are suppressed, and the pattern layer 120 is processed with good quality. is making it feasible.

For this reason, in the wafer processing method according to Embodiment 1, the first output, which is the average output of the laser beam 11 irradiated in the passivation film processing step 1001, is the laser beam irradiated in the pattern layer processing step 1002. It is smaller than the second output, which is the average output of the light ray 21. Alternatively, the energy density around 1 spot of the laser beam 11 irradiated in the passivation film processing step 1001 is smaller than the energy density around 1 spot of the laser beam 21 irradiated in the pattern layer processing step 1002. .

In Embodiment 1, since the passivation film 130 is a polyimide film that is weak to heat and may melt due to heat, the use of the laser beam 11 with such a low average output causes peeling and deterioration of the polyimide film. Since not only damage but also melting can be suppressed, the effect of suppressing heat damage to the passivation film 130 becomes more significant. Additionally, even when the passivation film 130 is an oxide film or a nitride film, peeling, deterioration, or damage to the oxide film or nitride film can be suppressed.

In Embodiment 1, since the pattern layer 120 is thick, with a thickness of 10 μm or more and 100 μm or less, the use of the laser beam 21 with such a large average output provides good quality for the pattern layer 120. The effect of making processing feasible becomes more remarkable. Additionally, in Embodiment 1, the average power (first output) of the laser beam 11 is, for example, 1.1 W, and the average power (second output) of the laser beam 21 is, for example, 6.4 W. It's W.

The laser beam 11 is preferably pulsed and has a pulse width in the picosecond or femtosecond range. Here, the pulse width in the range of picoseconds or femtoseconds refers to a pulse width of 10 ^-15 seconds or more and 10 ^-12 seconds or less in Embodiment 1. In the wafer processing method according to Embodiment 1, the pulse width of the laser beam 11 is set in the range of picoseconds or femtoseconds, and further, the passivation film 130 in the passivation film processing step 1001 Heat damage can be suppressed. In addition, when the pulse width of the laser beam 11 is less than 10 ^-15 seconds, it is difficult with the currently available technology. On the other hand, when the pulse width of the laser beam 11 is greater than 10 ^-12 seconds, the passivation film ( 130) There is a risk that heat damage to the body may increase.

Additionally, it is preferable that the laser beam 11 has a higher repetition frequency than the laser beam 21. In addition, it is preferable that the laser beam 11 has a faster transfer speed of the converging point with respect to the wafer 100 than that of the laser beam 21.

In the wafer processing method according to Embodiment 1, the repetition frequency of the laser beam 11 is made larger than that of the laser beam 21, and the transfer speed of the converging point of the laser beam 11 is set to be faster than that of the laser beam 21. By doing so quickly, it is possible to achieve good quality processing of the pattern layer 120 while suppressing heat damage to the passivation film 130 in the passivation film processing step 1001.

Additionally, in Embodiment 1, the repetition frequency of the laser beam 11 is, for example, 3000 kHz, and the repetition frequency of the laser beam 21 is, for example, 800 kHz. Additionally, in Embodiment 1, the transport speed of the converging point of the laser beam 11 is, for example, 1000 mm/s, and the transport speed of the converging point of the laser beam 21 is, for example, 850 mm/s. .

In addition, the width 161 of the first processing groove 151 formed in the passivation film processing step 1001 is wider than the width 162 of the second processing groove 152 formed in the pattern layer processing step 1002. . For this reason, in the wafer processing method according to Embodiment 1, the laser beam 21 irradiated to form the second processing groove 152 in the pattern layer processing step 1002 is used to form the first processing groove 151. It is possible to prevent peeling, deterioration, or damage of the passivation film 130 by irradiating the passivation film 130 away from the edge or the first processing groove 151.

FIG. 6 is a cross-sectional view illustrating the substrate processing step 1003 of FIG. 1. The substrate processing step 1003 is a step of processing the substrate 110 along the second processing groove 152, as shown in FIG. 6 . Additionally, the direction in which the second processing groove 152 extends is along the division line 112 .

In the substrate processing step 1003, the substrate 110 is processed along the extending direction of the second processing groove 152, that is, along the division line 112, by various methods, and the second processing groove ( The substrate 110 is further dug downward in the thickness direction from the bottom surface of 152) to form a third processing groove 153 (see FIG. 6).

In the substrate processing step 1003, in Embodiment 1, the bottom surface of the third processing groove 153 is additionally brought to the back surface 114 of the substrate 110 (back surface 104 of the wafer 100) to form a substrate ( By passing through 110, the substrate 110 is divided along the division line 112, and the wafer 100 is divided to manufacture a plurality of device chips.

In the substrate processing step 1003, in Embodiment 1, the third processing groove 153 is formed with a width 163 narrower than the width 162 of the second processing groove 152. For this reason, in the wafer processing method according to Embodiment 1, when forming the third processing groove 153 in the substrate processing step 1003, the edge of the first processing groove 151 or the first processing groove 151 ), it is possible to prevent the passivation film 130 from peeling, deteriorating, or damaging the passivation film 130 by processing it, and the edge of the second processing groove 152 or the second processing groove 152 It is possible to prevent peeling, deterioration, or damage of the pattern layer 120 by processing the pattern layer 120 away from the surface.

In Embodiment 1, the substrate processing step 1003 can be performed, for example, by the methods of the first, second, third, fourth, and fifth examples described below. In addition, the substrate processing step 1003 is not limited to this in the present invention, and may be performed by combining some of the methods of Examples 1 to 5, etc.

The substrate processing step 1003 is performed by plasma etching in the first example method. In the first example of the substrate processing step 1003, specifically, the side protective film deposition step of covering the side surfaces of the first processing groove 151, the second processing groove 152, and the third processing groove 153 with a side protective film. and a deep digging processing step in which the bottom surface of the second processing groove 152 or the bottom surface of the third processing groove 153 is dug downward in the thickness direction of the wafer 100 by plasma etching.

The side protective film deposition step is a step of supplying a predetermined plasma gas from the surface 101 side of the wafer 100 and depositing a side protective film using the supplied plasma gas. In the deep digging processing step, after depositing the side protective film in the side protective film deposition step, a predetermined plasma gas different from that in the side protective film deposition step is supplied from the surface 101 side of the wafer 100, and the supplied plasma gas The side protective film deposited on the bottom surface of the third processing groove 153 is removed, and the substrate 110 on the bottom surface of the third processing groove 153 is plasma etched to deepen the third processing groove 153. It's a step.

In the first example of the substrate processing step 1003, in Embodiment 1, a so-called Bosch process is performed in which the side protective film deposition step and the deep digging processing step are alternately repeated in separate processes to form a first processing groove ( 151), the etching amount of the side surfaces of the second processing groove 152 and the third processing groove 153 is sufficiently smaller than the etching amount of the bottom surface of the third processing groove 153 to form a third processing groove with a high aspect ratio ( 153). In addition, in the first example of the substrate processing step 1003, the present invention is not limited to this, and the side protective film deposition step and the plasma etching step are performed simultaneously to form a third processing groove 153 with a high aspect ratio. It's also good.

In the second example method, the substrate processing step 1003 is performed by cutting using a cutting blade. In the second example of the substrate processing step 1003, specifically, a cutting blade thinner than the width 162, which is mounted on the tip of a predetermined spindle and subjected to a rotational motion around the axis along the Y-axis direction by the spindle, is predetermined. After moving along the Z-axis direction by the lifting unit of the second processing groove 152 and cutting it into the substrate 110 to a predetermined depth, the spindle (cutting blade) is moved to the wafer 100 by a predetermined driving source. ), the substrate 110 is cut along the division line 112 with a cutting blade by relatively moving the second processing groove 152 along the extending direction, thereby forming the division line 112. A third processing groove 153 is formed along the substrate 1010 and has a depth reaching the back surface 114 of the substrate 110, thereby dividing the substrate 110 along the division line 112.

In the third example method, the substrate processing step 1003 is performed by irradiating a laser beam of a wavelength having transparency to the substrate 110 of the wafer 100. In the third example of the substrate processing step 1003, specifically, a laser beam having a wavelength that is transparent to the substrate 110 of the wafer 100 is formed on the wafer 100 by a predetermined laser irradiator. While irradiating toward the substrate 110 exposed on the bottom surface of the second processing groove 152, the wafer 100 is relatively transported and moved along the division line 112 with respect to the laser irradiator by a drive source (not shown). By doing so, this laser beam creates a modified layer inside the substrate 110 along the division line 112, and cracks extending toward the front surface 111 and the back surface 114 starting from the modified layer. The substrate 110 is divided along the division line 112 using this modified layer or crack as the third processing groove 153. Here, the modified layer means a region in which density, refractive index, mechanical strength or other physical properties are different from those of the surrounding area, and includes a melt-processed region, a cracked region, an insulating breakdown region, a refractive index change region, and these. Examples include areas where areas are mixed.

In the method of the fourth example, the substrate processing step 1003 is performed by grinding the back surface 114 side of the substrate 110 in addition to irradiation of the same laser beam as in the third example. In the fourth example of the substrate processing step (1003), specifically, as in the third example, a modified layer and a crack are formed by irradiating a laser beam, and then the modified layer and the crack are formed, and then the spindle is mounted on the tip of the spindle and moves in the Z-axis direction by the spindle. A grinding wheel having grinding stones arranged in an annular shape and subject to rotational motion around the axis is moved along the Z-axis direction by a predetermined lifting unit to move the back surface 114 of the substrate 110 of the wafer 100 positioned below. ) By contacting and pressing the side, the substrate 110 is ground to a predetermined thickness with a grinding wheel, and the third processing groove 153 (crack) is made to reach the back surface 114 side, dividing the substrate 110. Divide along the predetermined line 112.

In the fifth example method, the substrate processing step 1003 is performed by irradiating a laser beam of a wavelength having absorptive properties to the substrate 110 of the wafer 100. In the fifth example of the substrate processing step 1003, specifically, a laser beam having a wavelength that is absorptive to the substrate 110 of the wafer 100 is formed on the wafer 100 by a predetermined laser irradiator. While irradiating toward the substrate 110 exposed on the bottom surface of the second processing groove 152, the wafer 100 is relatively transported and moved along the division line 112 with respect to the laser irradiator by a drive source (not shown). By doing this, the substrate 110 is laser processed (so-called ablation processing) along the division line 112 with this laser beam, and the substrate 110 is penetrated along the division line 112. By forming a third processing groove 153 with a depth reaching the back surface 114 of , the substrate 110 is divided along the division line 112.

In the wafer processing method according to Embodiment 1 having the above configuration, after processing the passivation film 130 with the laser beam 11 of the first output, the pattern layer 120 is processed with the laser beam 11 having a first output. Since processing is performed with the laser beam 21 of output 2, heat damage to the passivation film 130 is suppressed, peeling, deterioration, and damage are suppressed, and the pattern layer 120 can be processed with good quality, The passivation film 130 has the effect of processing the wafer 100 stacked on the pattern layer 120 with good quality.

In addition, in the wafer processing method according to Embodiment 1, the substrate processing step 1003 divides the substrate 110 to form a plurality of device chips, so the wafer 100 is formed into a plurality of device chips. Even when divided, the passivation film 130 can be appropriately left to protect the pattern layer 120 constituting the device chip or the device region 113 of the substrate 110.

In addition, in the wafer processing method according to Embodiment 1, since the passivation film 130 is made of polyimide, it is weak to heat and may melt due to heat due to the use of the laser beam 11 with a low average output. Since peeling, deterioration, and damage of the polyimide film as well as melting can be suppressed, the effect of suppressing heat damage to the passivation film 130 becomes more significant.

In addition, in the wafer processing method according to Embodiment 1, since the passivation film processing step 1001 uses a laser beam 11 having a pulse width in the range of picoseconds or femtoseconds, the passivation film processing step 1001 also includes Heat damage to the passivation film 130 at 1001 can be suppressed.

In addition, in the wafer processing method according to Embodiment 1, since the width 161 of the first processing groove 151 is wider than the width 162 of the second processing groove 152, the pattern layer processing step 1002 ), the laser beam 21 radiating from the edge of the first processing groove 151 or the first processing groove 151 irradiates the passivation film 130 to peel, deteriorate, or damage the passivation film 130. can be suppressed from doing so.

[Embodiment 2]

A wafer processing method according to Embodiment 2 of the present invention will be described based on the drawings. FIGS. 7, 8, and 9 are all cross-sectional views illustrating the passivation film processing step 1001 of the wafer processing method according to Embodiment 2. 10, 11, and 12 are cross-sectional views illustrating the pattern layer processing step 1002 of the wafer processing method according to Embodiment 2. 7 to 12, the same parts as those in Embodiment 1 are given the same reference numerals, and description thereof is omitted.

The wafer processing method according to Embodiment 2 is a method in which the passivation film processing step (1001) and the pattern layer processing step (1002) in Embodiment 1 are changed, respectively.

In the passivation film processing step 1001 in Embodiment 2, before irradiation of the laser beam 11, as shown in FIG. 7, the wafer ( A top protective film 170 is formed on the surface 101 (exposed surface 131 of the passivation film 130) of 100, and as shown in FIG. 8, a laser beam 11 is irradiated to produce a laser beam ( 11), the top protective film 170 and the passivation film 130 are laser processed along the dividing line 112 to form a first processing groove 151. After forming the first processing groove 151, Figure 9 As shown, it was changed to remove the top protective film 170.

In the passivation film processing step 1001 in Embodiment 2, for example, before irradiation of the laser beam 11, the wafer 100 is placed with the surface 101 facing upward using a holding table (not shown). While holding and rotating the wafer 100 on the holding table by rotating the holding table around an axis parallel to the vertical direction, liquid resin is supplied to the wafer 100 on the holding table by a resin supply nozzle (not shown). Liquid resin is applied on the passivation film 130 of the wafer 100 by discharging it toward the surface 101, and the applied liquid resin is dried to form a surface on the passivation film 130 of the wafer 100. Forms a top protective film 170 that protects.

The liquid resin applied in the passivation film processing step (1001) in Embodiment 2 is a water-soluble resin, for example, polyvinyl alcohol (PVA) or polyvinyl pyrrolidone (PVP). etc. The top protective film 170 formed in the passivation film processing step 1001 in Embodiment 2 is used to passivate debris (processing debris) of the passivation film 130 generated by laser processing by irradiation of the laser beam 11. Prevents adhesion to the upper surface of the membrane 130. In the passivation film processing step 1001 in Embodiment 2, a water-soluble resin film is formed as the top protective film 170.

In the passivation film processing step 1001 in Embodiment 2, for example, after forming the first processing groove 151, the wafer 100 is placed on the surface 101 side (top protective film) using a holding table (not shown). The side on which (170) is formed is held upward, the wafer 100 on the holding table is rotated by rotating the holding table around an axis parallel to the vertical direction, and a cleaning liquid supply nozzle (not shown) is used to supply the cleaning liquid. The top protective film 170 is removed by discharging the wafer 100 toward the top protective film 170 on the surface 101 side of the wafer 100 on the holding table. The cleaning liquid is, for example, pure water or a two-fluid mixture of pure water and compressed air, and dissolves the top protective film 170, which is a water-soluble resin film.

In the pattern layer processing step 1002 in Embodiment 2, before irradiation of the laser beam 21, as shown in FIG. 10, a wafer ( A top protective film 170 similar to the passivation film processing step 1001 in Embodiment 2 is formed on the surface 101 (exposed surface 131 of the passivation film 130) of 100, and is shown in FIG. 11. As shown, the laser beam 21 is irradiated and the top protective film 170 and the pattern layer 120 are laser processed along the division line 112 to form the second processing groove 152. And, after forming the second processing groove 152, the top protective film 170 is removed, as shown in FIG. 12.

In the wafer processing method according to Embodiment 2, in Embodiment 1, in the passivation film processing step (1001) and the pattern layer processing step (1002), the top protective film 170 is applied before irradiation of the laser beams 11 and 21, respectively. ) is formed, and the top protective film 170 is removed after irradiation of the laser beams 11 and 21 (after formation of the first processing groove 151 and the second processing groove 152), so that the implementation It exerts the same effect as Form 1.

In addition, in the wafer processing method according to Embodiment 2, the top protective film 170 further suppresses peeling, deterioration, and damage of the passivation film 130 and forms a passivation film 130 on the exposed surface 131. This is a preferred form that can reduce the risk of debris attaching to the pattern layer 120.

In addition, the present invention is not limited to this, and is not limited to cases in which the debris of the passivation film 130 and the pattern layer 120 generated in the passivation film processing step 1001 and the pattern layer processing step 1002 is small, respectively, or when the passivation film processing step 1002 is not limited to this. In cases where attachment of debris to the exposed surface 131 of the film 130 does not affect the quality of the device chip, the wafer processing method according to Embodiment 1 can be followed by omitting the formation of the top protective film 170. You can do it. That is, formation of the top protective film 170 is not essential for the present invention.

Additionally, the present invention is not limited to the above embodiments. In other words, the present invention can be implemented with various modifications without departing from the gist of the present invention.

11, 21 laser beam
100 wafers
110 substrate
101, 111 surface
112 Line scheduled for division
120 pattern layer
130 Passivation film
151 1st machining groove
152 2nd machining groove
161, 162, 163 width

Claims (5)

A wafer processing method in which a wafer having a pattern layer formed on the surface of a substrate and a passivation film covering the pattern layer is processed along a line to be divided, comprising:
A passivation film processing step of forming a first processing groove in the passivation film by irradiating a laser beam with a first output along the division line;
A pattern layer processing step of forming a second processing groove in the pattern layer by irradiating a laser beam of a second output greater than the first output along the first processing groove;
A wafer processing method comprising a substrate processing step of processing the substrate along the second processing groove. According to paragraph 1,
The wafer processing method is characterized in that the substrate processing step produces a plurality of chips by dividing the substrate. According to paragraph 1,
A wafer processing method, characterized in that the passivation film is polyimide. According to paragraph 1,
The passivation film processing step is a wafer processing method, characterized in that using a laser beam having a pulse width in the range of picoseconds or femtoseconds. According to paragraph 1,
A wafer processing method, characterized in that the first processing groove is wider than the width of the second processing groove.