JP2010283070A - Method of manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor device that suppresses the occurrence of a projection or the like on the back surface of a substrate during marking using a laser etc. <P>SOLUTION: A semiconductor substrate 1 having a circuit formed on one surface 1a thereof has an organic resin layer 2 formed on the other surface 1b on the opposite side from the one surface 1a, the organic resin layer 2 is irradiated with a laser beam from above to remove organic resin at the predetermined position of the organic resin layer 2, and the other surface 1b of the semiconductor substrate 1 is irradiated with a laser beam penetrating the organic resin layer 2 to form recessed parts 4a, 4b at positions 3a, 3b where the organic resin is removed on the other surface 1b of the semiconductor 1, thereby marking the back surface of the semiconductor substrate. After the marking, the organic resin layer 2 is removed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a manufacturing method for marking a back surface of a semiconductor substrate in a semiconductor device such as a wafer level CSP (Chip Size / Scale Package) that does not use a wiring substrate (interposer).

  In a manufacturing method generally called “wafer level CSP” (for example, see Non-Patent Documents 1, 2, and 3), an insulating layer, a rewiring layer, a sealing resin layer, and the like are formed on a silicon wafer, and solder bumps are formed. . In the final step, the wafer is cut (divided into pieces) into a predetermined chip size, whereby a semiconductor chip having a package structure can be obtained. A feature of the wafer level CSP manufacturing method is that all the materials constituting the package are processed in the shape of the wafer. That is, the insulating layer, the rewiring layer, the sealing resin layer, the solder bump, and the like are all formed by handling the wafer (see, for example, Patent Documents 1 and 2).

Also, wafer backside grinding is performed to reduce the size and height of semiconductor devices. At this time, a processing strain (fracture layer) is generated on the back surface of the wafer, which may cause warpage of the wafer 1 shown in FIG. 7 indicates a plane in contact with the wafer back surface 1b.
In response to this problem, Patent Document 3 discloses that a resin layer is formed on the back surface of the wafer, and the warpage of the wafer after back surface grinding is reduced by balancing the stress between the front surface and the back surface of the wafer. A method for suppressing chipping and cracking is described. However, in the method described in Patent Document 3, since the resin layer remains even in the semiconductor chip after being singulated, it is necessary to select a mounting process that enables mounting of the chip while having the resin layer. is there.

JP 2004-207368 A International Publication No. 00/77844 JP 2007-227497 A

Nikkei Microdevice February 2000, p. 42 Nikkei Microdevice March 2000 issue, p. 121 Nikkei Microdevice April 2000, p. 114

Conventionally, a lot number, a product name, and the like are marked on the back surface of a silicon substrate by a laser. However, as shown in FIG. 8, when marking was performed by directly irradiating the wafer back surface 1 b with the laser beam L, it occurred when the concave portion 4 to be marked was formed around the portion irradiated with the laser beam L. Protrusions or the like 10 formed by adhering pieces of material constituting the wafer 1 are generated. When the chip is taken out from the tape attached to the back surface of the wafer after singulation, the protrusions 10 are peeled off and the device or apparatus is contaminated.
On the other hand, a method of coating a resin on the back surface of the wafer in advance and marking the resin is also performed, but the marking formed on the resin is difficult to recognize and the substrate becomes thick.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for manufacturing a semiconductor device capable of suppressing the occurrence of protrusions on the back surface of a substrate during marking using a laser or the like. And

  In order to solve the above-described problems, the present invention provides a method for manufacturing a semiconductor device in which a circuit is formed on one surface of a semiconductor substrate and a marking is applied to the other surface, the organic substrate being formed on the other surface of the semiconductor substrate. Forming a resin layer; irradiating a laser from above the organic resin layer to remove an organic resin at a predetermined position of the organic resin layer; and passing the laser penetrating the organic resin layer to the semiconductor substrate Irradiating the other surface of the semiconductor substrate, forming a recess at a position where the organic resin is removed on the other surface of the semiconductor substrate, and providing a step of marking and a step of removing the organic resin layer A method for manufacturing a semiconductor device is provided.

The organic resin layer can be formed by spin coating, spray coating, or laminating.
The semiconductor substrate is preferably in the form of a wafer.
The semiconductor substrate is preferably made of a semiconductor selected from Si, Ge, SiGe, SiC, SiSn, GaN, GaP, GaAs, InP, AlGaAs, PbS, and ZnSe.

  According to the present invention, when marking using a laser or the like, it is possible to suppress adhesion of the material generated when forming the recess to the back surface of the substrate, and even if the fragments are attached to the organic resin layer, the organic resin When the layer is peeled, debris and the like can be removed from the semiconductor device. Thereby, it is possible to perform marking directly on the back surface of the substrate, and it is possible to suppress the occurrence of protrusions and the like due to adhesion of debris on the back surface of the substrate.

(A)-(g) is typical sectional drawing which shows the process of the manufacturing method by the 1st example of this invention in order. (A) is a back view corresponding to FIG. 1 (d), (b) is a back view corresponding to FIG. 1 (f), and (c) is a back view corresponding to FIG. 1 (g). (A)-(c) is typical sectional drawing which shows each process of the method of performing laser marking from the top of a resin layer in order. (A)-(g) is typical sectional drawing which shows the modification of the 1st form example of this invention. (A)-(g) is typical sectional drawing which shows the process of the manufacturing method by the 2nd example of this invention in order. 5A is a back view corresponding to FIG. 5D, FIG. 5B is a back view corresponding to FIG. 5E, and FIG. 5C is a back view corresponding to FIG. It is typical sectional drawing explaining the curvature of a wafer. (A) It is typical sectional drawing explaining a mode that a back surface of a board | substrate is irradiated with a laser and (b) a protrusion etc. generate | occur | produce.

Hereinafter, based on the form for implementing this invention, this invention is demonstrated with reference to drawings.
FIGS. 1A to 1G are schematic cross-sectional views sequentially showing each step of the manufacturing method according to the first embodiment. 2 (a) is a back view corresponding to FIG. 1 (d), FIG. 2 (b) is a back view corresponding to FIG. 1 (f), and FIG. It is a back view corresponding to g). FIGS. 3A to 3C are schematic cross-sectional views sequentially showing each step of the method of performing laser marking from the top of the resin layer.

In this embodiment, as shown in FIG. 1A, a wafer 11 having a circuit or an element such as an integrated circuit (IC) formed on one surface 1a is used as a semiconductor substrate. Although it does not specifically limit as the semiconductor substrate 11, For example, what consists of various semiconductors selected from the group which consists of Si, Ge, SiGe, SiC, SiSn, GaN, GaP, GaAs, InP, AlGaAs, PbS, ZnSe. Can be mentioned.
Next, in order to reduce the thickness of the semiconductor device, a back grinding process for grinding the back surface 1c (the back surface before grinding) of the wafer 11 is performed after the circuit / element forming process (the pre-process) is completed. Grind to the thickness of. Thereby, as shown in FIG.1 (b), the semiconductor substrate 1 by which the back surface 1b (back surface after grinding) was ground is obtained. In FIG. 1, the semiconductor substrate 11 before grinding and the semiconductor substrate 1 after grinding are distinguished from each other.

Next, the organic resin layer 2 is formed on the back surface 1 b which is the other surface 1 b of the semiconductor substrate 1. The organic resin used for forming the organic resin layer 2 is not particularly limited, but various resins such as liquid or film (for example, polyimide (PI), polybenzoxazole (PBO), acrylic resin, epoxy) Resin, urethane resin, etc.). For the formation of the organic resin layer 2, a spin coat method, a spray coat method, a laminate method, or the like can be used. The organic resin layer 2 can be dried or cured as necessary.
The organic resin layer 2 is temporarily provided for marking, and is removed from the substrate 1 after marking. Therefore, even when the organic resin layer 2 is thick, there is no risk of increasing the thickness of the semiconductor device.

  Since it is desirable that the warpage of the substrate 1 is small when marking is performed, the tensile stress of the resin is adjusted by adjusting the material and the thickness of the organic resin layer 2 formed on the ground substrate back surface 1b. By balancing the stress with the back surface 1b, the warpage of the substrate 1 after back surface grinding can be reduced. The required thickness of the organic resin layer 2 can be obtained based on the amount of warpage of the substrate 1 and the thickness of the substrate 1 before the resin layer is formed.

  Next, as shown in FIG. 3A, a laser L is irradiated from above the organic resin layer 2 to remove the organic resin at a predetermined position, and as shown in FIG. On the other surface (substrate back surface) 1b, a recess 4 is formed at a position (resin removing portion) 3 where the organic resin is removed. As shown in FIG. 1D and FIG. 2A, the resin removing unit 3 may be either a figure 3a with a closed line or a figure 3b with no line closed. 2A is the scribe line 7, and the resin removing portion 3 is formed on the inner side (chip portion) surrounded by the scribe line 7.

According to this embodiment, since the organic resin layer 2 is provided on the substrate back surface 1b to be marked, it is possible to suppress adhesion of the material fragments generated during the formation of the recesses to the substrate back surface 1b, Furthermore, even if debris or the like adheres to the organic resin layer 2, the debris or the like can be removed from the semiconductor device when the organic resin layer 2 is peeled off. Thereby, marking can be performed directly on the back surface 1b of the substrate, and generation of protrusions and the like due to adhesion of fragments on the back surface 1b of the substrate can be suppressed.
Furthermore, since the warpage of the substrate 1 is reduced by the organic resin layer 2, markings representing characters, symbols, and the like can be accurately applied to the substrate back surface 1b.
Examples of the laser used for laser marking include a carbon dioxide laser, a YVO ₄ laser, and a YAG laser.

The type of laser is not particularly limited, but a laser capable of removing both the organic resin layer 2 and the semiconductor substrate 1 by irradiation, such as a YVO ₄ laser and a YAG laser, is preferable.
As a result, as shown in FIG. 3B, when forming the resin removal portion 3 in the organic resin layer 2, the laser L penetrates the organic resin layer 2 and simultaneously irradiates the other surface 1 b of the semiconductor substrate 1. (Details start irradiation). That is, the marking recess 4 can be formed simultaneously with the formation of the resin removal portion 3. As shown in FIG. 2B, the marking recess 4 may be either a figure 4 a with a closed line or a figure 4 b with no line closed. 2B is the scribe line 7, and the marking recess 4 is formed inside (chip portion) surrounded by the scribe line 7.

  The circuit formed on one surface 1a of the semiconductor substrate 1 may be only a circuit built in the semiconductor substrate 1, such as an IC. In the case of this embodiment, as shown in FIG. Semiconductor package processing is performed on the surface 1a of 1. In the semiconductor package processing, for example, a stacked body 5 including an insulating layer, a rewiring layer, a sealing resin layer, and the like, and a bump 6 exposed to the outside of the stacked body 5 are formed by a method such as wafer level CSP. The redistribution layer is electrically connected to the electrode of the IC, and can include various circuit elements such as an inductor and a capacitor in addition to a function of connecting the electrode to a terminal such as the bump 6.

When processing the semiconductor package, a passivation film made of an insulator such as an oxide or nitride may be provided on the surface 1a of the semiconductor substrate 1. In this case, the passivation film has an opening at a position aligned with the electrode of the IC, and the rewiring and the electrode can be conducted through the opening.
The bump 6 can be formed by an electrolytic solder plating method, a solder ball mounting method, a solder paste printing method, a solder paste dispensing method, a solder vapor deposition method, or the like. It is preferable to use eutectic type or lead-free type solder.

Next, as shown in FIGS. 1 (f), 2 (b), and 3 (c), the organic resin layer 2 is removed after the marking recesses 4 (4a, 4b) are formed. Although the removal method of the organic resin layer 2 is not specifically limited, When removing by peeling, since a solvent etc. are not required and it is simple, it is preferable. It is preferable to remove the organic resin layer 2 before singulation because the entire wafer can be processed at once and the productivity is improved.
The semiconductor device shown in FIG. 1 (f) is a semiconductor device in which marking is performed at the wafer level on the back surface of a thin substrate that has been ground back. This semiconductor device can be used to manufacture a semiconductor chip 8 by dicing along a scribe line 7 as shown in FIGS. 1 (g) and 2 (c).

  The semiconductor package processing does not need to be performed after marking as shown in FIG. 1, and can be performed in an arbitrary order as long as it is before the wafer is separated. For example, as shown in FIG. 4, it can also be performed before the back surface grinding. FIG. 4 shows (a) after preparing an IC substrate before grinding, (b) semiconductor package processing, (c) back surface grinding, (d) resin layer formation, (e) laser marking, (f) resin layer This is a modified example in which each step is performed in the order of peeling and (g) singulation, and each step is the same as the embodiment shown in FIG.

As described above, according to the method for manufacturing a semiconductor device of this embodiment, the organic resin layer 2 is provided on the back surface 1b of the substrate to be marked, so that the fragments of material generated during the formation of the recesses. Can be prevented from adhering to the substrate back surface 1b, and even if debris or the like adheres to the organic resin layer 2, the debris or the like can be removed from the semiconductor device when the organic resin layer 2 is peeled off. Thereby, marking can be performed directly on the back surface 1b of the substrate, and generation of protrusions and the like due to adhesion of fragments on the back surface 1b of the substrate can be suppressed.
Furthermore, since the warpage of the substrate 1 is reduced by the organic resin layer 2, markings representing characters, symbols, and the like can be accurately applied to the substrate back surface 1b.

As mentioned above, although this invention has been demonstrated based on suitable embodiment, this invention is not limited to the above-mentioned example, Various modifications are possible in the range which does not deviate from the summary of this invention.
In the present invention, as in the second embodiment described later, the marking can be applied by etching instead of the laser. Further, the resin removal portion can be formed using a technique such as photolithography or stamp instead of the laser. When photolithography is used, the organic resin layer 2 is formed from a photosensitive resin.

  5A to 5G are schematic cross-sectional views sequentially showing each step of the manufacturing method according to this embodiment. 6 (a) is a back view corresponding to FIG. 5 (d), FIG. 6 (b) is a back view corresponding to FIG. 5 (e), and FIG. 6 (c) is shown in FIG. It is a back view corresponding to g).

  In this embodiment, as shown in FIG. 5A, after preparing the IC substrate 11 before grinding, the semiconductor package is processed as shown in FIG. 5B, and as shown in FIG. 5C. 4 is the same as the example shown in FIG. In this embodiment, as shown in FIG. 5 (d), when the organic resin layer 2 is formed on the back surface 1b of the substrate 1 after the back surface grinding, the shape of the marking is formed using a technique such as photolithography or stamping. In addition, resin removing portions 3a and 3b formed by removing the resin are formed. As shown in FIG. 6A, the resin removing portion may be either a figure 3a with a closed line or a figure 3b with no line closed. In the case of this embodiment, a resin removing portion 3c along the scribe line is also formed.

Next, as shown in FIG. 5 (e), through the organic resin layer 2 opened by the resin removing portions 3a and 3b, a part of the substrate material is removed by etching to form the recesses 4a and 4b. Marking is applied to the back surface 1 b of the substrate 1. In the case of this embodiment, a recess 4c along the scribe line is also formed on the back surface 1b of the substrate 1 by etching through the resin removal portion 3c along the scribe line. By forming such a recess 4c, dicing can be performed more easily in the singulation process.
According to this embodiment, since the organic resin layer 2 is provided on the substrate back surface 1b to be marked, it is possible to suppress adhesion of the material fragments generated during the formation of the recesses to the substrate back surface 1b, Furthermore, even if debris or the like adheres to the organic resin layer 2, the debris or the like can be removed from the semiconductor device when the organic resin layer 2 is peeled off. Thereby, marking can be performed directly on the back surface 1b of the substrate, and generation of protrusions and the like due to adhesion of fragments on the back surface 1b of the substrate can be suppressed.

A specific method of etching can be appropriately selected depending on the substrate material. In the case of a dry process (dry etching), plasma etching, reactive ion etching (RIE), or the like can be used. In the case of wet etching, for example, when the substrate material is Si, hydrofluoric acid (a mixture of nitric acid and hydrogen fluoride HF) can be used.
In the case of wet etching, it is preferable that debris and the like are dispersed in the etching solution, so that they are less likely to adhere to the substrate, and further, debris and the like having weak adhesion can be removed by washing with water or the like. The debris and the like attached to the organic resin layer 2 can be removed from the semiconductor device when the organic resin layer 2 is peeled off.

  After forming the concave portions 4a and 4b for the marking, the organic resin layer 2 is peeled and removed as shown in FIG. 5 (f) so that the back surface of the thinly ground substrate is marked at the wafer level. Is completed. As shown in FIGS. 5G and 6C, this semiconductor device can be used for manufacturing a semiconductor chip 8 by dicing into pieces.

According to the semiconductor device manufacturing method of the second embodiment, since the organic resin layer 2 is provided on the substrate back surface 1b to be marked, the substrate back surface 1b such as a piece of material generated during the formation of the recess. Even if debris or the like adheres to the organic resin layer 2, the debris or the like can be removed from the semiconductor device when the organic resin layer 2 is peeled off. Thereby, marking can be performed directly on the back surface 1b of the substrate, and generation of protrusions and the like due to adhesion of fragments on the back surface 1b of the substrate can be suppressed.
Furthermore, since the warpage of the substrate 1 is reduced by the organic resin layer 2, markings representing characters, symbols, and the like can be accurately applied to the substrate back surface 1b.
By forming the recess 4c along the scribe line on the back surface 1b of the substrate 1, dicing can be performed more easily in the singulation process.

  The present invention can be used for manufacturing a semiconductor package such as a wafer level CSP (Chip Size / Scale Package) without using a wiring board (interposer).

L ... Laser beam, 1 ... Semiconductor substrate (wafer), 1a ... One surface (front surface), 1b ... Other surface (back surface after grinding), 2 ... Organic resin layer, 3,3a, 3b, 3c ... Resin removal 4, 4 a, 4 b, 4 c... Marking recess, 8... Semiconductor chip, 10.

Claims (4)

A method of manufacturing a semiconductor device in which a circuit is formed on one surface of a semiconductor substrate and marking is applied to the other surface,
Forming an organic resin layer on the other surface of the semiconductor substrate;
Irradiating a laser from above the organic resin layer to remove the organic resin at a predetermined position of the organic resin layer, and irradiating the other surface of the semiconductor substrate with the laser penetrating the organic resin layer A step of marking by forming a recess at a position where the organic resin is removed on the other surface of the semiconductor substrate;
And a step of removing the organic resin layer.   The method of manufacturing a semiconductor device according to claim 1, wherein the organic resin layer is formed by a spin coating method, a spray coating method, or a laminating method.   The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor substrate has a wafer shape.   The semiconductor substrate is made of a semiconductor selected from Si, Ge, SiGe, SiC, SiSn, GaN, GaP, GaAs, InP, AlGaAs, PbS, and ZnSe. Semiconductor device manufacturing method.

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