JP2005072349A - Method of manufacturing semiconductor element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem in the conventional semiconductor element manufacturing method that the treating liquid such as acids or organic solvents, etc. used for processing the backside penetrates through through-holes 4 to dissolve a resist layer 3, this lowering the adhesive strength of a semiconductor wafer 2 to a subsidiary substrate 1 to result in the peel off and damage of the wafer 2. <P>SOLUTION: The semiconductor element manufacturing method comprises a step of adhering a subsidiary substrate 1 having many through-holes 4 to a semiconductor wafer surface 2a through two adhesive layers, i.e., a resist layer 3 and a fluoric resin layer 101, a step of processing the semiconductor wafer backside 2b, a step of drilling holes 102 in the fluoric resin layer 101 by plasma etching, and a step of penetrating an organic solvent 5 through the holes 102 to peel off the wafer 2 from the subsidiary substrate 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a semiconductor device, in which a semiconductor wafer is attached to an auxiliary substrate and reinforced so that the semiconductor wafer does not break even when the semiconductor wafer is thinned by backside polishing.

  For example, in the case of a semiconductor wafer made of a compound such as GaAs, after forming elements on the surface of the semiconductor wafer, the thickness is polished very thinly from the back side of the semiconductor wafer in order to reduce the thermal resistance. In order to prevent the mechanical strength from being reduced and the semiconductor wafer from cracking due to stress during the process, it is previously processed by being attached to an auxiliary substrate made of quartz or glass having rigidity with an adhesive.

  An example of a conventional method for manufacturing a semiconductor device is shown in FIG. FIG. 3 is a cross-sectional view of the main part showing the order of steps.

  In the conventional method of manufacturing a semiconductor device, first, as shown in FIG. 3A, an auxiliary substrate 1 made of glass and a semiconductor wafer 2 are attached. In the sticking procedure, for example, a resist layer 3 is formed on the surface 2a of the semiconductor wafer 2 as a sticking material, and the formed surface is pressed against the auxiliary substrate 1 while being heated.

  Here, the adhesive material formed on the semiconductor wafer 2 may be, for example, an acrylic resin or a special wax other than the resist, and is usually dissolved with an organic solvent such as methyl ethyl ketone, acetone, or isopropyl alcohol at the time of peeling. For this reason, the patch is excellent in solubility in these organic solvents. In the above description, the adhesive material is formed on the semiconductor wafer 2 side. However, the adhesive material may be formed on the auxiliary substrate 1 side.

  As shown in FIG. 4, the auxiliary substrate 1 is provided with a large number of through holes 4 (diameter: about several hundred μm). The purpose of providing the through-hole 4 is to escape bubbles generated when the semiconductor wafer 2 and the auxiliary substrate 1 are pasted, and an organic solvent can easily enter through the through-hole 4 and dissolve the pasting material at the time of peeling. It is to do.

  Next, as shown in FIG. 3B, the back surface 2b of the semiconductor wafer 2 is thinly polished with a back surface polishing apparatus (not shown) so as to have a desired thickness (the polishing portion is indicated by a one-dot chain line in the drawing). After that, for example, a via hole (not shown) penetrating from the back surface 2b side to the front surface 2a side of the semiconductor wafer 2 is formed using a photolithography method, or after an acid treatment as a pretreatment, a vacuum deposition method or the like. A predetermined metal film is formed, and backside processing such as washing and drying is performed for each treatment. At this time, since the acid and organic solvent used in these treatments enter the through holes 4 of the auxiliary substrate 1, the resist layer 3 is exposed to the acid and organic solvent.

  Next, when the back surface processing is completed, as shown in FIG. 3C, the joined body of the auxiliary substrate 1 and the semiconductor wafer 2 is immersed in an organic solvent 5 for peeling (for example, methyl ethyl ketone, acetone, isopropyl alcohol, etc.). Then, the resist layer is dissolved, and the auxiliary substrate 1 and the semiconductor wafer 2 are peeled off.

  At this time, the organic solvent 5 penetrates through the numerous through holes 4 provided in the auxiliary substrate 1 in addition to entering the inside from the outer peripheral portion of the semiconductor wafer 2, so that the dissolution rate of the resist layer can be further increased. .

  As described above, when the semiconductor wafer 2 is attached to the auxiliary substrate 1 in advance and processed on the back surface, even if the thickness of the semiconductor wafer 2 is reduced and the mechanical strength is reduced, it is possible to prevent cracking due to stress during the process. Further, if a large number of through holes 4 are provided in the auxiliary substrate 1, the peeling speed can be improved.

Thereafter, the semiconductor wafer 2 is divided into individual pellets (not shown) by dicing (not shown) or the like (see, for example, Patent Document 1).
JP 2002-184845 A (2nd page, paragraphs 0003 to 0005, FIG. 5)

  However, in the above-described semiconductor element manufacturing method, since the auxiliary substrate 1 is provided with a large number of through holes 4, a treatment liquid such as an acid or an organic solvent used in each processing of the back surface penetrates the auxiliary substrate 1. It penetrates through the holes 4 and undesirably dissolves the resist layer 3 to reduce the bonding strength between the auxiliary substrate 1 and the semiconductor wafer 2, resulting in a problem that the semiconductor wafer 2 is peeled off and damaged during the process. there were.

  An object of the present invention is a semiconductor in which a treatment liquid such as an acid or an organic solvent used in each processing of backside processing enters through a through hole of the auxiliary substrate and does not reduce the bonding strength between the auxiliary substrate and the semiconductor wafer. It is providing the manufacturing method of an element.

The method for manufacturing a semiconductor device of the present invention includes:
at least,
A pasting step of pasting a semiconductor wafer surface and an auxiliary substrate provided with a large number of through-holes through two layers of adhesive layers made of different adhesive materials;
A back surface processing step of performing predetermined processing on the exposed semiconductor wafer back surface;
A perforating step of making a hole in the adhesive layer on the auxiliary substrate side of the two adhesive layers through the through hole;
A method for manufacturing a semiconductor element, comprising: a peeling step of removing the adhesive material layer on the semiconductor wafer side through a hole opened in the adhesive material layer on the auxiliary substrate side and separating the auxiliary substrate and the semiconductor wafer. is there.

  According to the method for manufacturing a semiconductor element of the present invention, the adhesive material for adhering the auxiliary substrate and the semiconductor wafer is made of two layers made of different adhesive materials, and the adhesive material on the semiconductor wafer side is excellent in solubility in an organic solvent for peeling. Since it is a sticking material, the peeling speed can be improved. On the other hand, the adhesive strength on the auxiliary substrate side is reduced even if the processing liquid enters from the through hole provided in the auxiliary substrate in order to make the adhesive material on the side of the auxiliary substrate less soluble in the processing liquid used in the back surface processing. There is no worry.

  An example of a method for manufacturing a semiconductor device of the present invention is shown in FIGS. 1 and 2 are cross-sectional views of the main part showing the order of steps. The same parts as those in FIG. 3 are denoted by the same reference numerals.

  In the method of manufacturing a semiconductor element of the present invention, first, as shown in FIG. 1A, an auxiliary substrate 1 made of glass and a semiconductor wafer 2 are attached. In the sticking procedure, for example, a resist layer 3 is formed on the surface 2a of the semiconductor wafer 2 as a sticking material. On the other hand, for example, a fluorine resin layer 101 is formed on the auxiliary substrate 1 as a sticking material. And while heating, the formation surfaces are pressed against each other and pasted together.

  Here, the adhesive material formed on the semiconductor wafer 2 may be, for example, an acrylic resin or a special wax other than the resist, and is usually dissolved with an organic solvent such as methyl ethyl ketone, acetone, or isopropyl alcohol at the time of peeling. Therefore, a patch having excellent solubility in these organic solvents is preferable.

  On the other hand, as the adhesive material to be formed on the auxiliary substrate 1, an adhesive material excellent in organic solvent resistance and acid resistance is used as a protective layer against a treatment liquid such as acid and organic solvent used in the subsequent back surface processing step. And For example, a fluororesin is suitable because it is excellent in mechanical strength and heat resistance. The thickness of the formation layer is determined in consideration of both the strength as a protective film and the ease of removal in a subsequent process.

  In the above description, the adhesive material is described as being formed on the semiconductor wafer 2 and the auxiliary substrate 1 by one layer each. However, two layers may be laminated on one side.

  As shown in FIG. 4, the auxiliary substrate 1 is provided with a large number of through holes 4 (diameter: about several hundred μm). The purpose of providing the through-hole 4 is to escape bubbles generated when the semiconductor wafer 2 and the auxiliary substrate 1 are pasted, and an organic solvent can easily enter through the through-hole 4 and dissolve the pasting material at the time of peeling. It is to do.

  Next, as shown in FIG. 1B, the back surface 2b of the semiconductor wafer 2 is thinly polished with a back surface polishing apparatus (not shown) so as to have a desired thickness (in the figure, the polishing portion is indicated by a one-dot chain line). ), For example, a via hole (not shown) penetrating from the back surface 2b side of the semiconductor wafer 2 to the front surface 2a side is formed using a photolithography method, or after an acid treatment as a pretreatment, a vacuum deposition method or the like. A predetermined metal film is formed, and backside processing such as washing and drying is performed for each treatment.

  At this time, an acid or an organic solvent used for the back surface processing enters the through hole 4 of the auxiliary substrate 1, but the resist layer 3 is protected by the fluororesin layer 101, so that it melts to lower the adhesive strength. There is no.

  Next, when the back surface processing is completed, as shown in FIG. 2C, the fluorine-based resin layer 101 is removed by plasma etching from the back surface side of the auxiliary substrate 1 through the through holes 4, and the holes 102 are formed in the fluorine-based resin layer 101. To open the resist layer 3.

  Next, as shown in FIG. 2D, the joined body of the auxiliary substrate 1 and the semiconductor wafer 2 is immersed in a peeling organic solvent 5 (for example, methyl ethyl ketone, acetone, isopropyl alcohol, etc.), and the organic solvent 5 Is introduced through the hole 102 formed in the outer peripheral portion of the semiconductor wafer 2 and the fluorine-based resin layer 101 to dissolve the resist layer 3 and peel off the auxiliary substrate 1 and the semiconductor wafer 2.

  At this time, since the organic solvent 5 permeates through the numerous through holes 4 provided in the auxiliary substrate 1 in addition to intrusion from the outer periphery of the semiconductor wafer 2, the dissolution rate of the resist layer 3 can be further increased. Can do.

  As described above, when the semiconductor wafer 2 is attached to the auxiliary substrate 1 in advance and processed on the back surface, even if the thickness of the semiconductor wafer 2 is reduced and the mechanical strength is reduced, it is possible to prevent cracking due to stress during the process. In addition, since a large number of through holes 4 are provided in the auxiliary substrate 1 and the back surface processing is protected by the fluorine-based resin layer 101 having excellent treatment liquid resistance, the treatment liquid intrudes from the through holes 4 to reduce the adhesive strength. There is no worry to let you. Further, at the time of peeling, the fluorine-based resin layer 101 is previously removed by plasma etching, and the organic solvent 5 is infiltrated through the through holes 4, so that the peeling speed can be improved.

  Thereafter, the semiconductor wafer 2 is divided into individual pellets (not shown) by dicing (not shown) or the like.

  The present invention can be applied to a backside processing process of a semiconductor wafer where there is no fear that the acid or organic solvent used for each processing of the backside permeates through the through hole of the auxiliary substrate and lowers the pasting strength of the pasting material.

Sectional drawing of the principal part of process order of an example of the manufacturing method of the semiconductor element of this invention Sectional drawing of the principal part of process order of an example of the manufacturing method of the semiconductor element of this invention Cross-sectional view of relevant parts in the order of steps in a conventional method for manufacturing a semiconductor device Plan view and sectional view of auxiliary board

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Auxiliary substrate 2 Semiconductor wafer 2a The surface of a semiconductor wafer 2b The back surface of a semiconductor wafer 3 Resist layer 4 Through-hole 5 The organic solvent for peeling 101 Fluorine-based resin layer 102 The hole opened in the fluorine-based resin layer

Claims (5)

at least,
A pasting step of pasting a semiconductor wafer surface and an auxiliary substrate provided with a large number of through-holes through two layers of adhesive layers made of different adhesive materials;
A back surface processing step of performing predetermined processing on the exposed semiconductor wafer back surface;
A punching step of making a hole in the adhesive layer on the auxiliary substrate side of the two adhesive layers through the through hole;
A semiconductor device comprising: a peeling step for removing the adhesive material layer on the semiconductor wafer side through the holes formed in the adhesive material layer on the auxiliary substrate side and separating the auxiliary substrate and the semiconductor wafer. Device manufacturing method.   Of the two adhesive layers, the auxiliary substrate side adhesive layer is made of an adhesive material that is less soluble in the processing liquid used in the back surface processing step, and the semiconductor wafer side adhesive material layer is The method for producing a semiconductor element according to claim 1, wherein the semiconductor element is made of an adhesive material excellent in solubility in an organic solvent.   3. The method of manufacturing a semiconductor element according to claim 2, wherein the adhesive material layer on the auxiliary substrate side is made of a fluorine-based resin, and the adhesive material layer on the semiconductor wafer side is made of a resist.   4. The method for manufacturing a semiconductor device according to claim 1, wherein the perforating method is dry etching.   In the peeling method, a solvent excellent in solubility in the adhesive layer on the semiconductor wafer side is allowed to enter through the hole formed in the outer peripheral portion of the semiconductor wafer and the adhesive layer on the auxiliary substrate side, and the semiconductor wafer The method of manufacturing a semiconductor element according to claim 1, wherein the method is a method of dissolving the side adhesive material layer.

Images