JPH04283930A - Wiring board and manufacture thereof - Google Patents

Abstract

PURPOSE:To furnish a structure in which a minute residue which is left after etching of a protective insulating (BPSG) film containing boron and phosphorus in the surface and causes a fault in nonvolatile memory LSI of 1 megabit or above, or the like, is removed in a wiring board comprising a semiconductor integrated circuit element etc., and to provide a manufacturing method thereof. CONSTITUTION:It is ascertained that a residue left on the surface of a BPSG film on the occasion of light etching of the film is element phosphorus contained in the BPSG film. Therefore, the residue left on the occasion when the film is light-etched with a liquid containing a fluoric acid is removed by etching it with a nitric acid, ammonia water or the like.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] With the increasing density of semiconductor integrated circuits, there is an increasing demand for miniaturization and higher density of wiring boards including semiconductor elements and wiring used for interconnecting them. It is well known that one of the biggest challenges in forming a high-density wiring board is how to overcome the height difference that increases with the stacking of elements and wiring. For example, Homma et al., Journal of Electrochemical Society, Vol. 135, No. 10, 2557-2.
The paper on page 567 describes an aluminum alloy (hereinafter referred to as Al) whose cross section has been made almost flat by absorbing the underlying level difference and forming a SiO2 film with a flat surface by bias sputtering using a planar magnetron cathode. ) describes a technique for forming two-layer wiring. These are intended to form a protective insulating film at a temperature sufficiently lower than the melting point of Al.

On the other hand, when the wiring conductor layer is made of a material with a higher melting point, such as a metal silicide, processing at a higher temperature may be used to form or stabilize a protective insulating film. can. BP adhered to the wiring board of the present invention
SG film has been widely used in recent years as a simple and excellent method that flows at a lower temperature of 900 degrees Celsius or less than glass containing only P, which has been widely used until now, and can flatten the film surface regardless of the unevenness of the element surface. It is used.

[0003] The present invention relates to this BPSG film, in which the P contained therein is substantially close to single P.
It is characterized by being a film that does not contain any. In addition, the concentration of P near the surface of such a BPSG film is
The film is characterized in that it does not have a region with a higher concentration than other parts inside the film, or it does not have a residue mainly composed of P with a size of 0.5 μm or more.

The present invention relates to a wiring board having a fine conductor wiring pattern, in particular, whose cross-sectional structure is gently smoothed, and the film quality of the protective insulating film of the conductor layer is suitable for finer wiring and higher reliability. It is characterized by the fact that it is

In particular, the present invention provides a structure that enables miniaturization of wiring without deteriorating element characteristics or wiring reliability when a BPSG film is used to cover wiring or the surface of an element in a wiring board. The present invention relates to a method and an apparatus for manufacturing the same.

[0006]

2. Description of the Related Art A BPSG film is widely used as a protective film for elements having a flattening effect and metal silicide wiring. Generally, monosilane (SiH4) is added while adding P or B.
) as the main raw material gas, chemical vapor deposition (Chemical VaporDep) is applied onto integrated circuit elements and wiring.
A film is formed by a CVD method (hereinafter referred to as CVD method). When a BPSG film is just formed, its quality is not sufficient, such as the film is not dense, and it does not have a flattening effect. Apply heat treatment. This heat treatment atmosphere gas includes an atmosphere containing hydrogen (hereinafter referred to as a reducing atmosphere), an atmosphere containing oxygen (hereinafter referred to as an oxidizing atmosphere),
Alternatively, either pure nitrogen or Ar atmosphere (hereinafter referred to as inert gas atmosphere) is generally used. The temperature is 850
A temperature range of ˜900° C. is used, which causes the film to flow and flatten the surface.

[0007] Regarding the influence of atmospheric gas during heat treatment on film quality and substrate properties, Tottori reported in the Proceedings of the 51st Annual Conference of the Japan Society of Applied Physics, 1990, Paper No. 26a-D.
-10 states that an oxidizing atmosphere makes fluidization more effective. However, when heat treatment is performed in an oxidizing atmosphere, the characteristics of integrated circuit elements in the wiring board deteriorate, such as an increase in interface states and leakage current. However, this characteristic deterioration did not pose much of a problem, for example, in a wiring board including an integrated circuit element having a minimum processing size of about 1.3 μm or more, because the characteristic margin was sufficiently large. After this, BPSG
Connection holes are formed in the required locations of the film to establish connections between elements and wiring or between wirings.

By the way, after forming the contact hole and before forming the wiring conductor layer thereon, in most cases, light etching is performed with a solution containing hydrofluoric acid (hereinafter referred to as "light etching") to form the BPSG film. A process is performed to clean the substrate surface exposed at the surface and the bottom of the connection hole.

The inventors used BPS during this light etching.
It was discovered that irregularly shaped residues were generated on the substrate surface including the G film. The occurrence of this residue changes depending on the concentration of B and P in the BPSG film. The higher the concentration of P in the film, the more conspicuous the generation of residue. When the P concentration is the same, there is a tendency for the individual residues to become larger as the B concentration is higher. The degree of occurrence is particularly remarkable in films that have been heat-treated in a reducing atmosphere. Further, the residue remains in various shapes depending on the method of cleaning and drying the substrate after etching. When a conventional drying method is used, such as a rotary dryer for substrates, which mainly works by rotating the substrate to blow away moisture, the residue is generally small, and at best the length of the substrate is small. The thickness is also thin, about 1 μm.

[0010] Therefore, it is difficult to observe this residue by distinguishing between the interference color of the BPSG film and the color of the residue itself using an ordinary optical microscope using a white light source. Even if the degree of occurrence is quite severe, it is often judged as a variation in etch depth because it only looks like color unevenness, and it may not necessarily be recognized as a problem with residue generation, or it may be due to process variations. In most cases, it was determined that the defect occurred suddenly. Furthermore, since the wiring and connection holes in conventional wiring boards were not so fine, the presence of these foreign substances did not immediately lead to the occurrence of defects.

[0011] As described above, conventional BPSG films tend to produce residues or a layer containing a high concentration of P due to light etching, etc., which is a pretreatment for forming wiring conductor layers, but their presence is almost nonexistent. without being recognized, and
In conventional wiring boards including integrated circuit elements, deterioration of characteristics and reliability has not been a problem.

0012

However, in recent years, semiconductor integrated circuit elements and wiring included in wiring boards have been miniaturized, and when the minimum processing size has become 0.8 μm or less, the characteristics of elements and wiring have become smaller. It has become necessary to improve reliability, reduce variation, etc. For example, as devices become smaller, the amount of charge accumulated per device decreases, so leakage currents and increases in interface states that occur when heat-treated for fluidization in an oxidizing atmosphere are unacceptable characteristics. This results in deterioration. Conversely, if the residue generated from the BPSG film heat-treated in a reducing atmosphere adheres to the connection hole between the element and the wiring, it may cause variations in connection resistance, and if it adheres to the bottom of the wiring, it may cause deterioration of adhesive properties. However, the minimum processing size is 0.
．． In the case of wiring and connection holes that are miniaturized to 8 μm or less, connection resistance and variation increase beyond the allowable limit, wiring peels, etc., making it difficult to meet the specifications required for integrated circuits. Therefore, it is necessary to use a reducing or inert atmosphere as the heat treatment atmosphere for fluidization.

Furthermore, as substrates become larger and devices become smaller, it is not desirable for safety to rotate large substrates at high speeds, and foreign matter in the air tends to adhere to them as they rotate. Drying methods using heat, steam, or gas are increasingly used. When such a drying method is used, the residue tends to become large, and the residue often becomes extremely large. In order to suppress the occurrence of such defects, it is necessary not to generate residues, or even if they occur, to suppress them to a size smaller than the dimensions of the wiring and connection holes. As a guideline, it should be about 60% or less of the minimum processing size that will be used for the time being, i.e. 0.8 μm (residues should be as small as possible, the smaller the better, but residues of 0.5 μm or less are difficult to observe depending on optical methods), i.e. 0. It is thought that it is necessary to suppress the size to about .5 μm or less. In addition, some of these residues may float inside the etch solution or cleaning solution tank.
It adheres to other substrates during etching or cleaning, causing defects.

[0014] If the residue generated in this way is stored for a long time in an atmosphere containing moisture, it will gradually change and the boundary around the foreign object will gradually become vague, making it difficult to see that the residue has disappeared at first glance. It exhibits the following condition. However, in reality, there is a thin layer on the surface of the film that has changed from the residue, and if a wiring conductor layer is provided on top of this, it will still cause peeling, which will lower the reliability of the wiring. Note that this residue has a P concentration of 4
It hardly occurs when it is less than mol%. However, at such a low concentration, it is necessary to increase the heat treatment temperature to cause fluidization of the BPSG film, and the planarization effect is limited. Therefore, such residues are P in the BPSG film.
It can be assumed that the substance is mainly composed of .

The present invention provides a substrate in which such residues on the surface of the BPSG film are substantially removed, and a method for manufacturing the same.

[0016] Generally, the P concentration in the BPSG film is 6 mol%.
The above concentration is used. However, it is said that the upper limit of the concentration of P that can form a solid solution in the SiO2 film that is the base material of the BPSG film, that is, that can be combined with Si, is about 4 mol %. Therefore, it has been conventionally believed that excess P in the BPSG film exists as oxides such as P2O5. However, the inventors have discovered that this idea is not necessarily correct.

That is, it has been found that a considerable proportion of the excess P in the BPSG film exists as metastable P, which substantially corresponds to simple P. When a BPSG film containing such metastable P is etched with a solution containing hydrofluoric acid, a residue mainly containing metastable P is generated on the film surface. It has been found that if the substrate is left in this state, the residual P reacts with moisture and becomes an oxide or hydroxide, turning into the above-mentioned thin layer with a high P concentration.

The reason why such a residue or thin layer has rarely been a problem in the past is that it has been difficult to observe in the past. For example, B is 9.8 mol%, P
A film containing 7.5 mol% of
Volume ratio: ammonium fluoride solution is a 50% aqueous solution. Even if the surface is observed with an optical microscope using a white light source after etching with a buffered etch solution for about 80 seconds, washing with water, and drying, no foreign matter can generally be detected. As mentioned above, this is because the residue is small and thin, making it extremely difficult to distinguish it from the interference color of the surrounding BPSG film and detect it. At best, when a special drying method is used and the residue becomes large, it is treated as a unique case.

However, it has been found that the residue can be observed quite easily when observed using a microscope that has been developed in recent years and uses a monochromatic light source such as a laser beam as a light source. It has also been found that this residue is almost insoluble in water, hydrofluoric acid, etc. that constitute an etchant when etching a BPSG film, but it is soluble in nitric acid and aqueous ammonia. Such chemical properties are known for simple P. That is, the source of this residue suggests that a portion of the P in the BPSG remained on the substrate surface during etching, with the main component being simple P.

In other words, the BPSG film subjected to the heat treatment in the reducing atmosphere described above contains a component not as P2O5 but as metastable P in a state substantially equivalent to simple P. .

FIG. 1 shows the state of P in this BPSG film using an XPS analysis method (X-ray Photoelectro).
The results are shown below using n Spectroscopy. The figure shows B heat-treated at 900℃ in a reducing atmosphere.
Regarding the PSG film and the film heat-treated in an oxidizing atmosphere,
The peak position and intensity (corresponding to the number of electrons) of the energy of electrons emitted from the 1s orbit of B or the 2s orbit of P are compared and shown. Since the energies of the two are the same, it is not possible to distinguish between the two here. When an insulating film is analyzed by the XPS method, due to the charge-up phenomenon,
The spectrum shifts. Therefore, in order to compare the results of the two samples, calibration was performed using the peak of Si in the BPSG film as a reference.

In the figure, the peak position of electrons from the film heat-treated in a reducing atmosphere is approximately 196.9 eV, and the peak position of electrons from the film heat-treated in an oxidizing atmosphere is approximately 19 eV.
It is 7.3eV. The electron peak position of the film heat-treated in a reducing atmosphere is 0.4 to 0.5 eV lower than the electron peak of the film heat-treated in an oxidizing atmosphere, and there is a large amount of elemental P or B. or exists as a compound state with a low valence. However, this peak is the overlap of B and P,
It is not possible to determine whether this change is due to a change in B or P.

Next, FIG. 2 shows the results of light etching the film heat-treated in a reducing atmosphere with a solution containing hydrofluoric acid to generate a residue on the surface, and analyzing the surface using the XPS method.
The energy peak positions and intensity distributions of electrons in the 1s orbit of B and the 2s orbit of P are shown. Note that this measurement result has not been calibrated against the influence of charge-up, so the peak position itself deviates by about 2 eV from the case in FIG. 1, but if it is calibrated using the Si peak position as a reference, it will match.

The results shown in the same figure show that 197e, which also appeared in FIG.
In addition to the peak near V, extremely strong 189-190e
A peak near V appeared. This was present in the membrane,
Indicates reduced P or B. In addition, Figure 2
In the measurement shown in , there is a strong P at a position that does not overlap with the peak of B.
A 2p peak appeared. From this, 189~ in Figure 2
It can be said that the peak around 190 eV is due to reduced P. In other words, the residue has been reduced and is almost a simple substance.
We can conclude that it consists of metastable P. This metastable P is not thought to have been reduced by the solution containing hydrofluoric acid, but is considered to have been contained in this state in the film.

To summarize the above results, after a BPSG film containing a large amount of P is heat-treated in a reducing or inert atmosphere, a part of it is converted into metastable P, which corresponds to elemental P, in the film. exists in Strictly speaking, metastable P in the present invention is a substance whose main component is P, which dissolves in nitric acid and aqueous ammonia but is difficult to dissolve in liquids containing water and hydrofluoric acid. For example, in the case of an unetched film measured by XPS analysis, 1s of B and P
The energy peak position of the 2s orbital electron is about 0.4
It is a film that decreases eV. This decrease in energy at the peak position indicates that a part of the P in the film has become metastable P. Furthermore, when the light-etched film surface was evaluated by XPS analysis, in addition to the combined P, almost no combined P was found.
Although P in a chemical state close to that of a simple substance is detected, this is also referred to as metastable P in the present invention.

Although the peak position of metastable P was significantly shifted to around 190 eV when the measurement was performed with the residue present on the surface, it seems that the peak position of metastable P shifted only around 0.4 eV in the measurement shown in FIG. This appearance is considered to be due to the sensitivity of the XPS analysis method for determining the amount of impurities. The energy measurement resolution of the XPS method is sufficiently high, 0.4 eV.
The difference between the peaks is significant, but the impurity detection sensitivity is 1
%, which is not necessarily high. Also, because we were analyzing an extremely shallow layer near the surface, we were unable to detect a sufficient P signal, and although a peak around 197 eV was detected as the sum of B and P electrons, the signal due to metastable P It is thought that the shift was only 0.4 eV because the shift was not strong enough.

The reason why the residue generated from the conventional BPSG film described above did not become a problem was that it was difficult to observe the residue, and the processing dimensions of the elements and wiring on the substrate were not very small, so the residue did not become a problem. This is thought to be because even if it occurred, it did not immediately lead to the occurrence of a defect. There are also differences in cleaning methods.

[0028]

Means for Solving the Problems By setting the P concentration in the BPSG film to 4 mol % or less, it is possible to suppress the generation of such residues and a thin layer containing P as a main component, which is generated by changing from the residues. Generally, the P concentration that can be dissolved in SiO2 is 4mo.
This is consistent with the phenomenon of less than 1%. However, such a film with a low P concentration is not suitable for planarization.

In the present invention, after light etching the BPSG film surface with a solution containing hydrofluoric acid as a pretreatment for forming a wiring metal layer, a solution containing an oxidizing substance, such as a solution containing nitric acid, hydrogen peroxide, or phosphoric acid, is used. Alternatively, by immersing the substrate in a solution containing a strong alkaline substance such as ammonia or hydrazine hydrate and dissolving the generated residue, metastable P
To provide a wiring board in which a high concentration P layer or a large residue mainly composed of P of 0.5 μm or more does not exist on the surface even if it is a BPSG film containing P.

If the heat treatment for fluidization is performed in an oxidizing atmosphere, no residue will be generated in the BPSG film even by light etching using a solution containing hydrofluoric acid. This is thought to be because P in the film is oxidized. but,
The electrical characteristics of the element deteriorate. On the other hand, if the device is heat-treated in a reducing atmosphere gas, the device characteristics are good, but the light etching process before forming the wiring metal layer generates a residue, which deteriorates the wiring characteristics. The present invention aims to clarify the cause of this residue and the main components of the residue, and to provide a means for etching it and a wiring board to which the same is applied.

Among the oxidizing substances mentioned in the present invention, nitric acid is particularly effective. In addition, as an alkaline substance, ammonia water is particularly effective because it can etch the residue or surface layer mainly composed of P without etching Si.

[0032]

[Operation] In the manufacture of wiring boards, if the board is a semiconductor board containing integrated circuit elements, the treatment to clean the exposed board surface after connection holes are formed is a treatment mainly based on chemical reactions, such as hydrofluoric acid. In most cases, it is unavoidable to use a light etch using a liquid or vapor containing . When high-energy plasma or ion treatment is used, the selectivity of the reaction is poor and no residue is produced, but it may reduce the crystallinity of the substrate material exposed at the bottom of the connection hole, or the redeposition phenomenon caused by plasma treatment may cause or pollute. In order to avoid such problems, it is necessary to increase the chemical reactivity as much as possible when using treatments such as plasma.
It is necessary to suppress damage and contamination caused by plasma energy. However, in treatments based on chemical reactions, the selectivity of the reaction is high, so substances in the film that do not react under the treatment conditions accumulate on the surface. The influence of these residues on elements and wiring becomes more serious as they become finer. The metastable P residue described in the present invention is also an example. Furthermore, cleaning with water or steam is required after light etching. In recent years, cleaning techniques to replace water have been studied, but a sufficiently versatile method has not yet been found. The above-mentioned residue cannot be sufficiently removed even by this washing.

On the other hand, in the wiring board and its manufacturing method of the present invention, by etching the residue mainly composed of P generated by light etching, the residue mainly composed of P and its reaction are removed. High concentration of P generated by
Since the P layer is removed, the electrical characteristics of the device are maintained in good condition, while a decrease in reliability due to the high concentration P layer on the surface is prevented.

However, if the substrate is exposed to a liquid containing an oxidizing substance such as nitric acid, the substance on the substrate surface exposed at the bottom of the contact hole formed in the BPSG film will be oxidized, and a wiring metal layer will be formed on it. In this case, electrical continuity between the wiring and the element may not be sufficiently good. In such a case, after etching the residue, light etching may be performed again using a solution containing a small amount of hydrofluoric acid. The oxide formed at the bottom of the connection hole by contact with the oxidizing liquid is not dense and is etched much more quickly than the BPSG film.
The light etching can be completed before the BPSG film is etched and almost no residue containing P as a main component is generated. Although some residue may occur, its size is 0.
．． It is sufficiently small, not exceeding 5 μm. Furthermore, since the density of occurrence is low, it hardly poses a problem to the substrate.

[0035]

[Example] Example 1 Ultraviolet erasable nonvolatile memory integrated circuit (hereinafter referred to as EPRO)
An example in which this method is applied to the following will be described. This is especially necessary for integrated circuits that include micro-sized elements of 1 megabit or more. Regarding EPROM, for example, Minami et al., IEICE technical research report, paper number SDM-1
1 and SDM90-135 (both published in 1990). The B concentration is 4m as a protective film for this element.
A BPSG film having a P concentration of 6 mol % and a P concentration of 6 mol % was deposited and heat treated at 850° C. in a mixed gas atmosphere of oxygen and nitrogen to fluidize the BPSG film and flatten the film surface. This heat treatment increases the interface level of the transistor used in the EPROM, causes the threshold voltage of the transistor to fluctuate, and deteriorates memory retention characteristics. Therefore, in order to make the information retention characteristics of the device sufficiently good, heat treatment was performed at 800℃ in a hydrogen atmosphere (
Hereinafter referred to as hydrogen annealing) was performed.

[0036] In such a substrate, connection holes between elements and wiring are further formed, and as a pretreatment for forming a wiring conductor layer,
When the substrate surface is lightly etched using the buffer etchant described above, a residue is generated on the element surface after washing with water and drying. The etching amount is approximately 20 nm in terms of the BPSG film.

In this example, after light etching, the substrate was further immersed in aqueous ammonia. The immersion time was 5 minutes, and the liquid temperature was about 23°C. The residue on the substrate surface was almost completely etched by this immersion. Then, as a wiring metal layer, A
An lSi alloy film was formed, and a wiring pattern was formed using known lithography and etching techniques.

[0038] As a result, fine wiring can be formed without increasing the interface state of the EPROM element or causing fluctuations in the threshold voltage, and without impairing the reliability of the wiring or the electrical connection characteristics between the wiring and the element. A substrate having the following structure was formed.

Embodiment 2 An example in which the present invention is applied to an EPROM will be described. This is especially necessary for integrated circuits that include micro-sized elements of 1 megabit or more. A BPSG film with a B concentration of 4 mol% and a P concentration of 6 mol% was deposited as a protective film for this element, and heat treatment was performed at 850°C in a mixed gas atmosphere of nitrogen and oxygen.
The membrane was fluidized to flatten the membrane surface. This heat treatment causes an increase in the interface state of the EPROM element and a fluctuation in the threshold voltage of the transistor, resulting in deterioration of memory retention characteristics. Therefore, in order to make the memory retention characteristics of the EPROM sufficiently good, heat treatment, that is, hydrogen annealing, was performed at 800° C. in a hydrogen atmosphere.

[0040] In such a substrate, connection holes between elements and wiring are further formed, and as a pre-treatment for forming a wiring conductor layer,
When the substrate surface is lightly etched using the buffer etchant described above, a residue is generated on the element surface after washing with water and drying. The etching amount is approximately 20 nm in terms of the BPSG film.

In this example, after light etching, the substrate was further immersed in nitric acid. The soaking time was 5 minutes, and the liquid temperature was about 2
It is 3℃. The residue on the substrate surface was almost completely etched by this immersion. However, in this process, the Si surface exposed at the bottom of the connection hole formed in the BPSG film may be oxidized, so the substrate is then light etched for 10 seconds using the 1:20 buffer etchant mentioned above, and then dried. Thereafter, an AlSi alloy film was formed as a wiring metal layer, and a wiring pattern was formed using known lithography and etching techniques. Light etching using a buffer etchant for about 10 seconds hardly etched the BPSG film, and therefore no residue was generated, so that no adverse effects were caused on the wiring or the electrical continuity between the wiring and the element.

[0042] As a result, fine wiring can be formed without increasing the interface state of the EPROM element or causing fluctuations in the threshold voltage, and without impairing the reliability of the wiring or the electrical connection characteristics between the wiring and the element. A substrate having the following structure was formed.

[0043]

The present invention provides a wiring board using a BPSG film that has been heat-treated in a reducing atmosphere to improve the electrical characteristics of the device. This heat treatment causes metastable P to be included in the film, and etching the BPSG film using a buffer etchant or the like deteriorates the reliability of the wiring and the electrical conductivity between the wiring and the element. However, if the present invention is applied and a wiring board with a structure in which the generated residue is removed is realized, the electrical characteristics of the device can be maintained well, and
Good wiring characteristics and reliability can also be maintained. The wiring board and its manufacturing method of the present invention described above are applicable to non-volatile memory circuits with an integration density of 1 megabit or more, where the integrated circuit elements included in the board are sensitive to leakage current and the level of interface states of the elements.
This is necessary for dynamic random access memory circuits with an integration density of 4 megabits or more.

[Brief explanation of the drawing]

FIG. 1 is a diagram comparing the bonding states of BPSG films subjected to heat treatment in a reducing atmosphere and heat treatment in an oxidizing atmosphere.

FIG. 2 is a diagram showing the bond energy of a light-etched surface of a film heat-treated in a reducing atmosphere.

Claims (7)

[Claims] Claim 1: 0.01 mol% or more of boron (hereinafter referred to as B
) and a glassy insulating film (Boro-Phospho) containing 4 mol% or more of phosphorus (hereinafter referred to as P).
Silicate Glass; hereinafter referred to as BPSG
) is adhered to at least a portion of the wiring board, the BPSG film contains metastable P which corresponds to a substantially simple substance, and the concentration of P on the surface of the BPSG film is as low as BPS.
A wiring board characterized in that it does not contain a layer having a higher concentration than other regions in a G film or particles having a size of 0.5 μm or more and containing P as a main component (hereinafter referred to as residue). 2. The wiring board according to claim 1, wherein the wiring board has a semiconductor integrated circuit. 3. The wiring board according to claim 2, wherein the semiconductor integrated circuit included in the board is a memory circuit of a dynamic random access memory, a static random access memory, or a nonvolatile memory, or a logic integrated circuit. A wiring board characterized by: 4. A wiring board having a semiconductor integrated circuit according to claims 2 to 3, characterized in that the minimum processing dimension of the wiring or electrode for the semiconductor integrated circuit is 0.8 μm or less. substrate. 5. The BPSG film used in the wiring board according to claims 1 to 4 is subjected to a heat treatment step at a temperature of 470° C. or higher in an atmospheric gas containing hydrogen, if necessary.
A method for manufacturing a wiring board, characterized in that a pre-treatment for forming a wiring conductor layer includes immersion in at least one of a liquid containing a strongly alkaline substance and a liquid containing a strongly acidic substance. 6. A method for manufacturing a wiring board, wherein the strongly alkaline substance according to claim 5 is hydrazine hydrate or ammonia. 7. A method for manufacturing a wiring board, wherein the strong acidic substance according to claim 5 is nitric acid.