JP4999801B2 - Etching method - Google Patents

Description

  The present invention relates to an etching method used in the fields of semiconductor device manufacturing, semiconductor package manufacturing, printed wiring board manufacturing, and the like. Specifically, the present invention relates to an etching method that prevents the contamination and deterioration of a substrate that occurs when the photoresist is removed after etching, and improves the quality of the product.

  In the industrial field as described above, a photoresist is used as a mask material for etching a substrate surface and forming a pattern film. Photoresist products are commercially available in varnish and film form. As a general usage method, a photoresist is formed on the substrate surface, a pattern is subsequently formed by photolithography, and then etching or film formation is performed on the substrate surface. Finally, an unnecessary photoresist is formed. Peel off. By carrying out this step, a structure having an arbitrary pattern can be formed on the substrate surface.

  A chemical is used to remove the photoresist after etching. This chemical solution is called a resist stripping solution (hereinafter referred to as stripping solution). A stripping solution is commercially available for each photoresist. As the peeling mechanism, an acid / base reaction or dissolution reaction between a photoresist and a peeling solution is used, and peeling generally proceeds by a chemical mechanism (see, for example, Patent Document 1).

  After stripping with the stripping solution of the photoresist, the stripping solution remaining on the substrate surface, the dissolved photoresist, and a mixture thereof tend to adhere thinly (hereinafter referred to as residues). For the removal, volatilization removal by chemical reaction with the activated reactive gas (hereinafter referred to as dry etching) is used. This method is called ashing, descum, desmear, etc., and is widely used. When post-processing is performed on a substrate from which residues are not removed, various defects occur. For example, the functional film formed on the residue may be peeled off, which may result in defective insulation and poor conduction of the final product.

  On the other hand, various taping processes are performed in manufacturing processes of semiconductor devices, semiconductor packages, printed wiring boards, and the like. As the tape material, the above-described film-like photoresist is one type, and other examples include BG tape, dicing tape, and protective tape. The use characteristic of the BG tape and the protective tape compared with the film-like photoresist is that no pattern is formed. These tapes are laminated over the entire surface. Thereafter, after the target processing is performed on the substrate, the tape is peeled off from the substrate. The laminated surface of the BG tape and dicing tape is generally the back surface of the substrate (the surface on which no processing is performed).

  A protective tape is also laminated to the backside of the substrate. Its use is for protection from scratches, dust, and contamination on the backside of the substrate, and furthermore, it is used in a variety of ways, including preventing breakage of thinned wafers and facilitating machine conveyance. The performance required for the protective tape is chemical resistance to various chemicals such as a plating solution, and thermal resistance up to about 250 ° C. These tapes are kept sticky during the plating and heating process and can be peeled off without any adhesive residue thereafter. The protective tape is peeled off by first laminating a high adhesive tape (hereinafter referred to as a peeling tape) on the surface of the protective tape. This adhesive strength is stronger than the adhesive strength between the protective tape / substrate. Due to this relationship, the protective tape is peeled off from the substrate surface in the process of peeling off the peeling tape.

  As described above, dry etching is used for residue removal. However, dry etching is problematic in that it increases processing costs and apparatus costs. Further, the dry process for removing the residue is an auxiliary work of the photoresist stripping process. If the stripping operation with the stripping solution is carried out well, it is an unnecessary operation, and this process is troublesome twice as far as possible.

  In the semiconductor and semiconductor package industries, introduction of TSV technology is under consideration. This technology originated from a MEMS device, and in recent years, its application has been expanded to ensure conduction between chips in three-dimensional mounting of device chips. The first step in TSV technology is the formation of through holes. The through hole is a structure in which a vertical hole having a diameter of several to several tens of μm is formed in a Si wafer of several tens to several hundreds of μm, and is characterized by a high aspect ratio depending on the application. For the formation of this structure, a method of performing dry etching using a photoresist mask is mainly used.

Consider a case where a substrate having such a through hole is immersed in a liquid. As described above, the through-hole having a high aspect ratio is difficult to get wet with the liquid, and even when wet, the diffusion of the liquid in the hole is worse than that of the substrate surface. For this reason, when the photoresist that has become unnecessary after the formation of the through hole is peeled off, the residue tends to remain in the through hole. Specifically, since the diffusion of the stripping solution that penetrates into the through hole is insufficient, the reaction rate in the hole is lowered and an insoluble photoresist remains or the photoresist in the hole is dissolved. In the subsequent water washing step, water is not diffused and the dissolved photoresist re-deposits in the holes. The above-mentioned tendency is not limited to the case of the through-hole, but is a common problem in the process of using a photoresist for a substrate having a rough surface with a trench or the like (see, for example, Patent Document 2). .
Japanese Patent No. 4009822 Japanese Patent No. 3719672

  The present invention has been devised in view of such conventional circumstances, and can prevent contamination of the substrate by residues in the removal of the photoresist after etching, and reduce the steps and costs for residue removal. It is an object to provide a possible etching method.

In the etching method according to claim 1 of the present invention, in etching of a substrate using a photoresist layer as a mask, a step A of providing an intermediate layer on the substrate and a pattern of the photoresist layer on the intermediate layer are provided. Step B for forming, Step C for patterning the intermediate layer via the photoresist layer, Step D for etching the substrate using the photoresist layer and the intermediate layer as a mask, and the photoresist Step E for providing a release layer on the layer and Step F for peeling the photoresist layer and the intermediate layer from the substrate at the same time by peeling the release layer in order, at least at the time of Step F The adhesive strength at the interface α between the release layer and the photoresist layer is higher than the adhesive strength at the interface β between the substrate and the intermediate layer. The intermediate layer and the release layer are provided so as to become higher.
The etching method according to claim 2 of the present invention is the etching method according to claim 1, wherein the adhesive force at the interface γ between the intermediate layer and the photoresist layer is higher than the adhesive force at the interface β. A layer is provided.
The etching method according to claim 3 of the present invention is characterized in that, in claim 1 or 2, a tape is used as the intermediate layer and / or the release layer.

  In the present invention, an intermediate layer is provided between the substrate and the photoresist layer, and in the resist peeling after etching, a peeling layer having high adhesive force is formed on the photoresist layer, and the peeling layer is peeled off. At the same time, the photoresist layer and the intermediate layer are peeled off from the substrate. Thereby, the photoresist removal process by the conventional stripping solution becomes unnecessary. In addition, residue generation after the photoresist is peeled off can be prevented, and a residue removal step by dry etching is not necessary. As a result, in the present invention, it is possible to provide an etching method that can prevent the substrate from being contaminated by residues and can reduce the steps and costs for removing the residues.

  Hereinafter, an embodiment of an etching method according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an example of the etching method of the present invention in the order of steps. Here, 1 is a substrate, 2 is a layer to be processed of the substrate, 3 is a first tape (intermediate layer), 4 is a photoresist layer, and 5 is a second tape (release layer).
In the following embodiment, the case where a tape is used as the intermediate layer and the release layer will be described as an example, but the present invention is not limited to this.
In the etching method of the present invention, in the etching of the substrate 1 using the photoresist layer 4 as a mask, the step A of providing the first tape 3 (intermediate layer) on the substrate 1, and the first tape 3, Step B for patterning the photoresist layer 4, Step C for patterning the intermediate layer via the photoresist layer 4, and the substrate 1 using the photoresist layer 4 and the first tape 3 as a mask. Etching step D, Step E providing a second tape 5 (release layer) on the photoresist layer 4, and peeling the second tape 5 at the same time, the photoresist layer 4 and the first layer. And a step F of peeling the tape 3 from the substrate 1.
And in this invention, at the time of the said process F, the adhesive force in the interface (alpha) of the said peeling layer (2nd tape 5) and the said photoresist layer 4 is the said board | substrate and the said intermediate | middle layer (1st tape 3). The intermediate layer and the release layer are provided so as to be higher than the adhesive force at the interface β.

  In the present invention, the first tape 3 (intermediate layer) is provided between the substrate 1 and the photoresist layer 4, and the second tape 5 (having high adhesive force on the photoresist layer 4 in the resist peeling after the etching) ( The photoresist layer 4 and the first tape 3 are peeled from the substrate 1 at the same time by providing the peeling layer) and peeling the second tape 5. This eliminates the need for a conventional photoresist layer removal step using a stripping solution. In addition, residue generation after the photoresist layer is peeled off can be suppressed, and a residue removal step by dry etching is not necessary. As a result, in the present invention, it is possible to provide an etching method that can prevent the substrate 1 from being contaminated by residues and can reduce the steps and costs for removing the residues.

  The present invention prevents the generation of residues in the removal of the photoresist layer 4 described above. That is, the present invention is characterized in that an easily peelable first tape 3 is provided as an intermediate layer between the photoresist layer 4 and the substrate 1. The first tape 3 is composed of the above-described protective tape, for example. After the processing is completed, the first tape 3 is physically peeled off, so that the photoresist layer 4 is also peeled off at the same time. The advantage of using this method is that the conventional step of stripping the photoresist layer with a stripper is omitted. Since this process is a process of generating a residue that has been a problem in the past, omission of the process results in eliminating the generation of the residue. Along with this, there is no need for a costly dry residue removal step.

Hereinafter, it demonstrates in order of a process.
(1) A first tape 3 (intermediate layer) is provided on the substrate 1 (step A).
First, as shown in FIG. 1A, the first tape 3 (intermediate layer) is provided on the surface of the layer 2 to be processed of the substrate 1. The first tape 3 need not be a photosensitive material such as the photoresist layer 4. The required performance is the ability to adhere to the substrate 1, the ability to be peeled after being processed into the layer to be processed 2, and the absence of adhesive residue after peeling. In addition, it is indispensable not to deteriorate or peel off in each process until the tape is peeled off.

The first tape 3 is desirably as thin as possible. Although the reason will be described later, it is because the processing accuracy of the post-processing is not impaired when briefly described.
A so-called protective tape is ideal as the first tape 3, but the present invention can also be implemented using a general BG tape or dicing tape. As a method of providing the first tape 3 on the substrate 1, lamination is preferable. As the lamination method, roll lamination is the simplest. When the unevenness of the surface of the substrate 1 is severe, it is preferable to use a vacuum laminator. The temperature at the time of lamination depends on the material of the tape, but in the case of a heat sensitive material, it is preferable to heat the material to an arbitrary temperature.

(2) A pattern of the photoresist layer 4 is formed on the first tape 3 (step B).
Subsequently, as shown in FIG. 1B, a photoresist layer 4 is formed on the substrate 1 on which the first tape 3 is laminated. As a film forming method, spin coating, spray coating, dip coating, or squeegee coating is used when the photoresist is varnished. In the case of a film, roll laminate or press laminate is used. After laminating, heating is performed according to the properties of the photoresist, and the solvent is removed by volatilization and adhesion with the substrate 1 is improved.

Then, as shown in FIG. 1C, a pattern is formed on the photoresist layer 4 by exposing and developing the photoresist. The exposure light source uses a light source that emits photosensitive wavelength light of a photoresist material, and irradiates a light amount suitable for the material and its film thickness. Similarly, development is performed using a developer suitable for the material. There are various development methods such as dip, paddle, spray, shower, etc., but any method may be used in the present invention.
Here, the adhesive force at the interface γ between the photoresist layer 4 and the first tape 3 needs to be higher than the adhesive force at the interface β between the substrate 1 and the previous first tape 3. Thereby, in the process (6) mentioned later, the photoresist layer 4 can be peeled with the 1st tape 3 without remaining.

  In the present invention, a patterned etching mask may be formed on the surface of the first tape 3, and the photoresist layer 4 is not necessarily used. For example, a non-photosensitive resin material may be applied by a printing method or a dispensing method to form a pattern, or a metal or ceramic material may be patterned using a lift-off method.

(3) The first tape 3 is patterned through the photoresist layer 4 (step C).
Subsequently, as shown in FIG. 1D, the exposed portion of the first tape 3 is removed through the photoresist layer 4. By this step, the work layer 2 is exposed to the outside air for the first time. As a removal method, any method such as wet etching using acid, aqueous alkali solution and organic solvent, dry etching, laser removal, or the like may be used. When the subsequent processing to the layer to be processed 2 is etching, the same method as the etching method to the layer to be processed 2 is preferably used. For this reason, it is desirable to employ a material that can be removed by the same method as the etching method for the layer 2 to be processed as the material of the first tape 3.

(4) Etching the substrate 1 using the photoresist layer 4 and the first tape 3 as a mask (step D).
Then, as shown in FIG.1 (e), the process to the to-be-processed layer 2 of the board | substrate 1 is implemented. FIG. 1 shows patterning by removing the layer 2 to be processed. As described above, any method such as wet etching, dry etching, or laser removal may be used as the method. The advantage of using the same method as the first tape 3 is that batch processing is possible.

(5) A second tape 5 (peeling layer) having high adhesive strength is provided on the photoresist layer 4 (step E).
Then, after the processing of the layer 2 to be processed, the photoresist layer 4 is peeled off. This process is a feature of the present invention.
In the present invention, peeling is completed through two steps. First, as shown in FIG. 1 (f), as the first stage of peeling, a second tape 5 is provided as a peeling layer on the surface of the photoresist layer 4.
The second tape 5 is configured such that the adhesive force at the interface α between the second tape 5 and the photoresist layer 4 is higher than the adhesive force at the interface β between the substrate 1 and the first tape 3. ing. The second tape 5 is a so-called release tape, and needs to be a material that adheres to the photoresist layer 4 with higher adhesive force than between the first tape 3 and the layer to be processed 2 (interface β). Many such products are commercially available, and their dimensions and adhesive strength can be appropriately selected as necessary.

  As a method of providing the second tape 5 on the surface of the photoresist layer 4, lamination is preferable. As a laminating method, roll laminating is the simplest as with the first tape 3. Note that vacuum lamination is not preferable. This is because the purpose of use of the second tape 5 is to peel off the first tape 3, and when the vacuum lamination is performed on the structure as shown in FIG. The purpose of use of the second tape 5 is to peel off the first tape 3, and the adhesion of the second tape 5 to the substrate 1 makes it difficult to peel off the first tape 3, and in addition, may cause adhesive residue on the substrate 1. There is. Therefore, it is preferable that the laminate of the second tape 5 is adhered to the surface of the photoresist layer 4 without a gap and has a gap on the processed portion. So-called tenting is the most ideal method.

(6) By peeling off the second tape 5, the photoresist layer 4 and the first tape 3 are simultaneously peeled from the substrate 1 (step F).
Subsequently, as shown in FIG. 1G, the laminated second tape 5 is peeled off. At this time, the adhesive force at the interface α between the second tape 5 and the photoresist layer 4 is higher than the adhesive force at the interface β between the substrate 1 and the first tape 3. 3 is peeled from the substrate 1. The photoresist layer 4 exists between the second tape 5 and the first tape 3, and is also peeled off as the first tape 3 is peeled off. At this time, since the adhesive force at the interface α between the photoresist layer 4 and the first tape 3 is higher than the adhesive force at the interface β between the substrate 1 and the previous first tape 3, the photoresist layer 4 Can be peeled off together with the first tape 3 without remaining. This process corresponds to the photoresist layer peeling process using a difficult liquid in the prior art.

  As described above, the material of the first tape 3 is selected so that there is no adhesive residue after peeling. Therefore, after the first tape 3 is peeled off, the residue that has been a problem in the prior art is not generated, and therefore, the residue removing step by dry etching that is frequently used in the prior art becomes unnecessary. As a peeling method of the 2nd tape 5, a commercially available tape peeling machine can be used. This process is a physical peeling work of the laminated tape, and the work is very simple.

  Previously, it was described that the thickness of the first tape 3 is desirably as thin as possible. The reason is as follows. In the prior art, the photoresist layer 4 serves as a mask material during etching. The cross-sectional shape of the photoresist layer 4 is a large factor that affects the processing accuracy of the base. In the present invention, the first tape 3 exists under the photoresist layer 4. Therefore, even when the cross-sectional shape of the photoresist layer 4 can be controlled to an ideal shape for the base processing, the processing accuracy of the base is impaired when the cross-sectional shape of the patterned first tape 3 cannot be controlled. It is. A general method for improving the patterning accuracy is to reduce the film thickness. For this reason, it is desirable that the thickness of the first tape 3 is small.

  Further, the etching mask made of the photoresist layer 4 reacts with the etchant to the base, and becomes thinner as the processing time increases, so that the entire surface of the layer 2 to be processed is finally exposed to the etchant. Therefore, a thick film is required for the photoresist layer 4. However, the surface of the first tape 3 in the present invention is covered with the photoresist layer 4 and is not exposed to the etchant. Therefore, it is not necessary to increase the film thickness, and a thin film is desirable.

Next, the pattern shape of the photoresist layer 4 that can be implemented in the present invention will be described.
FIG. 2 is a plan view schematically showing an example of a pattern of the photoresist layer 4 used in the present invention. Here, 7 is an exposed portion of the first tape 3, and 8 is an existing portion of the photoresist layer 4.
Since the exposed portion of the first tape 3 is removed before processing into the layer 2 to be processed, the first tape 3 exists only under the existing portion of the photoresist layer 4 when the first tape 3 is peeled off. Become. 2 (a) and 2 (b) differ in structure depending on whether or not the existence part of the photoresist layer 4 (the existence part of the first tape 3) is separated or connected in an island form. (A) is connected, and (b) is a solitary island.

  Such a difference in structure affects the feasibility of the present invention in the tape peeling process. A typical release tape is commercially available with a width narrower than the wafer diameter. This is because a general protective tape is not patterned in its application and the whole surface is connected, and if a part of the protective tape is peeled off, other portions can be peeled together. An example of the width of the peeling tape is 50 mm for 6 inches (d: 150 mm) and about 75 mm for 8 inches (d: 200 mm). When the present invention is carried out using such a general peeling tape as the second tape 5, the first tape 3 (where the second tape 5 is laminated in the solitary island structure as shown in FIG. 2B). The protective tape) is peeled off, but the first tape 3 at other locations remains on the substrate 1 as it is.

  On the other hand, if the structure is such that the first tape 3 is connected as shown in FIG. 2A, even if a general protective tape is used as the first tape 3, all tapes can be peeled off. It is. Therefore, in the practice of the present invention, a structure in which the first tape 3 is connected as shown in FIG. In other words, the pattern of the photoresist layer 4 is not a structure in which the photoresist layer 4 remains as a pattern, but a structure in which the pattern is missing in the photoresist layer 4 is preferable. As the latter structure, there are a through-hole pattern, a contact hole pattern, a wiring pattern by a semi-additive method, and the like as described later. As the former structure, there is a wiring pattern based on the subtractive method. In the case where the present invention is applied to such a structure, it is necessary to use a peeling tape having a width equal to or larger than the substrate diameter as the second tape 5. Such a tape is not commercially available but can be made.

Hereinafter, as one embodiment of the present invention, an implementation method when the present invention is used for forming a through hole will be described.
FIG. 3 is a schematic cross-sectional view sequentially showing the steps when a through hole is formed in the substrate 1 using the present invention. Here, 6 is a through hole.
The basic flow is the same as that shown in FIG. First, the first tape 3 is laminated on the surface of the substrate 1 (processed layer 2) [see FIG. 3A], and then a photoresist layer 4 is formed on the surface of the first tape 3 [see FIG. 3B]. And patterning (see FIG. 3C). Then, dry etching is performed on the first tape 3 and the substrate 1 [see FIGS. 3D to 3E].

  In dry etching to Si, a mixed reaction gas mainly composed of silicon fluoride gas and oxygen gas is used. As a material selection of the first tape 3, it is preferable to select a material to be etched by the mixed reaction gas. As a result, batch processing of the first tape 3 and the substrate 1 becomes possible, and productivity is improved. Alternatively, the etching gas for the first tape 3 and the Si etching gas can be switched after a predetermined time.

In dry etching of Si, the temperature of the substrate 1 tends to increase as the processing time increases. The temperature is generally 200 ° C. or lower, and the material of the first tape 3 must be selected so that there is no adhesive residue at the time of peeling even when heated to 200 ° C. In fact, such tape materials are commercially available as protective tape.
After the through-hole 6 is formed, the second tape 5 is laminated on the surface of the photoresist layer 4 [see FIG. 2 (f)], and the first tape 3 is peeled off together with the photoresist layer 4 by peeling it off. 3 (g)]. Through the above steps, the through holes 6 are formed in the substrate 1.

Next, the apparatus cost and man-hours in the etching process will be described in comparison with the case of using the conventional technique and the case of using the present invention.
The processing target is the above-described through-hole formation. First, as an apparatus, the prior art requires a photoresist layer peeling apparatus and a dry etching apparatus for removing residues. On the other hand, in the present invention, the above two devices are unnecessary, and instead, a tape laminating device and a tape peeling device are necessary. Although the necessary number of apparatuses is the same, in consideration of the fact that the dry etching apparatus is generally expensive, the apparatus cost decreases when the present invention is implemented.

  Next, with regard to the number of steps, the prior art is roughly divided into four steps: photolithography on the photoresist layer, dry etching for forming a through hole, peeling of the photoresist layer, and dry etching for removing a residue. On the other hand, the present invention includes four steps of tape lamination, photolithography on the photoresist layer, dry etching for forming a through hole, and tape peeling. There is no increase in man-hours due to the implementation of the present invention.

  As described above, in the present invention, an intermediate layer (first tape 3) that is easy to physically peel off is provided between the photoresist layer 4 and the substrate 1, and further, on the photoresist layer 4 after etching, it is high. A release layer (second tape 5) having adhesive strength is provided. Then, by peeling off the second tape 5, the photoresist layer 4 and the first tape 3 are simultaneously peeled from the substrate 1. This eliminates the need for a conventional photoresist layer removal step using a stripping solution. In addition, residue generation after the photoresist layer is peeled off can be suppressed, and a residue removal step by dry etching is not necessary. As a result, in the etching method of the present invention, it is possible to prevent the substrate 1 from being contaminated by residues, and it is possible to reduce processes and costs for removing the residues.

Note that the adhesive force relationship between the adhesive interfaces α, β, and γ is only required to be maintained during the resist stripping operation by the second tape 5, and the photoresist patterning step, the first tape 3 and the substrate 1 are etched. During the process, the adhesive force of the adhesive interface β may exceed the adhesive force of the adhesive interface α at the time of resist removal.
The protective tape assumed as the first tape 3 includes a kind of product that can be easily peeled off by reducing the adhesive strength with the substrate by heating the substrate during peeling. This type of tape exhibits strong adhesion at room temperature. The adhesive force between the first tape 3 and the substrate 1 is preferably strong from the viewpoint of resistance to photo processing and etching processing.
As an example of the work, the above heat-peelable tape is used as the material of the first tape 3. The adhesive force between the first tape 3 and the substrate 1 may be higher than the interfaces γ and α at room temperature. During the resist peeling operation after laminating the second tape 5, the substrate 1 is heated. By this heating, the adhesive strength of each interface becomes the above-described relationship, that is, α>γ> β.

  As the 1st tape 3 which concerns on this invention, a thing with high translucency is preferable. In the exposure operation in the patterning process of the photoresist layer, alignment between the substrate and the photomask is performed while visually recognizing the substrate surface pattern. At that time, if the translucency of the first tape 3 is low, the visual recognition becomes difficult, and alignment failure occurs. Since a general wavelength range as a light source for visual recognition of the exposure apparatus is 500 to 800 nm, it is ideal that the first tape 3 has a light transmittance of 80% or more in at least the wavelength region. Even when a non-photosensitive material is patterned by a printing method or the like, alignment under visual recognition is essential, and the above-described translucency is a factor that affects processing accuracy.

The etching process of the present invention has been described above, but the present invention is not limited to this example, and can be appropriately changed without departing from the spirit of the invention.
For example, in the above-described embodiment, the case where a tape (first tape and second tape) is used as an intermediate layer and a release layer will be described as an example, but the present invention is not limited to this, The intermediate layer and / or the release layer may be formed directly on the substrate or the photoresist layer.

  Moreover, for example, in the above-described embodiment, the case where the adhesive force at the interface with the adjacent layer is given a difference in the intermediate layer and the release layer has been described as an example, but the present invention is limited to this. For example, a layer having the same adhesive strength as an intermediate layer and a release layer may be provided, and before peeling, a method of making a difference in adhesive strength between two layers by a physical or chemical method. Good.

In FIG. 3, the thin skin portion present at the bottom of the substrate 1 is a functional layer on the surface of the substrate. For example, a semiconductor device corresponds to a resistor, an element, an electrode, or the like. Depending on the type of semiconductor device, a typical one has a thickness of 1 to 10 μm, and some MEMS devices have a thickness of ˜100 μm.
The through hole (through wiring) is formed for vertical conduction between the front surface and the back surface of the semiconductor device. In this case, the through hole has an I / O electrode in the functional layer at the bottom. A thin skin portion in FIG. 3 is drawn with the I / O electrode in mind.

  As described above, FIG. 3 is intended to form a bottomed through hole for ensuring conduction between the front surface and the back surface of the semiconductor device. On the other hand, as a form of through-hole formation, there is a (no bottom) structure that penetrates the substrate. Examples of applications that employ this structure include interposers used for semiconductor device stacking and printed circuit board contact holes. In these applications, the substrate having a thin skin portion in FIG. 3 also has a through-hole structure that penetrates through this, and when there is no thin skin portion, the through-hole structure penetrates through a bare substrate.

  When the present invention is applied to the through-hole forming step of the bottomed structure and the bottomless structure, a remarkable invention implementation effect can be obtained by using the bottomed structure as compared with the bottomless structure. The reason for this is that, when a resist stripping operation using a stripping solution, which is an existing technology, is performed, in the bottomless structure, the circulation (diffusion) of the stripping solution is relatively easy. This is because both the upper and lower sides of the hole are open, which facilitates the inflow and outflow of the liquid. In such a structure, the residue in the hole is suppressed by high-pressure spraying of the stripping solution or ultrasonic assistance. On the other hand, in the bottomed structure, since it is an opening on one side, the inflow and outflow of the stripping solution is clearly difficult, and a residue is likely to be generated in the hole after the resist stripping using the stripping solution.

  For this reason, a bottomed structure having a more remarkable effect is selected as an example of application of the present invention to the formation of a through hole, and this is illustrated in FIG. However, as is clear from the above description, it is needless to say that the present invention is not limited to a through hole having a bottomed structure, and may be applied to a through hole having a bottomless structure.

  The present invention is widely applicable to etching methods used in the fields of semiconductor device manufacturing, semiconductor package manufacturing, printed wiring board manufacturing, and the like.

It is typical sectional drawing which shows an example of the etching method of this invention in order of a process. It is a top view which shows typically an example of the pattern of the photoresist layer used in this invention. It is typical sectional drawing which shows an example which formed and processed the through-hole in the board | substrate using this invention in order of a process.

Explanation of symbols

  1 substrate, 2 layer to be processed, 3 first tape (intermediate layer), 4 photoresist layer, 5 second tape, 6 through-hole.

Claims (3)

In etching a substrate using a photoresist layer as a mask,
Step A for providing an intermediate layer on the substrate;
Step B of patterning a photoresist layer on the intermediate layer;
Patterning the intermediate layer through the photoresist layer; and
Etching the substrate using the photoresist layer and the intermediate layer as a mask,
Step E of providing a release layer on the photoresist layer;
Steps F in order to peel off the photoresist layer and the intermediate layer simultaneously from the substrate by peeling off the release layer,
At least at the time of Step F, the intermediate layer and the intermediate layer and the photoresist layer so that the adhesive force at the interface α between the release layer and the photoresist layer is higher than the adhesive force at the interface β between the substrate and the intermediate layer. An etching method comprising providing a release layer.   The intermediate layer and the release layer are provided so that the adhesive force at the interface γ between the intermediate layer and the photoresist layer is higher than the adhesive force at the interface β at least at the time of the step F. The etching method according to claim 1.   The etching method according to claim 1, wherein a tape is used as the intermediate layer and / or the release layer.

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